Rehabilitation Systems

SUMMARY
Physical activity, including appropriate endurance and resistance training,
is a major therapeutic modality for type 2 diabetes. Unfortunately, too often
physical activity is an underutilized therapy. Favorable changes in glucose
tolerance and insulin sensitivity usually deteriorate within 72 h of the last
exercise session; consequently, regular physical activity is imperative to
sustain glucose-lowering effects and improved insulin sensitivity. Individuals
with type 2 diabetes should strive to achieve a minimum cumulative
total of 1000 kcalzwk21 from physical activities. Those with type 2 diabetes
generally have a lower level of fitness (V˙ O2max) than nondiabetic individuals,
and therefore exercise intensity should be at a comfortable level (RPE
10–12) in the initial periods of training and should progress cautiously as
tolerance for activity improves. Resistance training has the potential to
improve muscle strength and endurance, enhance flexibility and body
composition, decrease risk factors for cardiovascular disease, and result in
improved glucose tolerance and insulin sensitivity. Modifications to exercise
type and/or intensity may be necessary for those who have complications
of diabetes. Individuals with type 2 diabetes may develop autonomic
neuropathy, which affects the heart rate response to exercise, and as a
result, ratings of perceived exertion rather than heart rate may need to be
used for moderating intensity of physical activity. Although walking may
be the most convenient low-impact mode, some persons, because of peripheral
neuropathy and/or foot problems, may need to do non-weightbearing
activities. Outcome expectations may contribute significantly to
motivation to begin and maintain an exercise program. Interventions designed
to encourage adoption of an exercise regimen must be responsive to
the individual’s current stage of readiness and focus efforts on moving the
individual through the various “stages of change.”
INTRODUCTION
Diabetes is one of the leading causes of death and disability
in the United States with type 2 diabetes accounting
for 90–95% of all diabetic cases (77). Based on national
data, there are about 10.3 million diagnosed cases of diabetes
in the United States with an estimated 5.4 million
additional undiagnosed cases in the general population (40).
Unfortunately, the diagnosis of type 2 diabetes is often
delayed for years after the onset of the disease. A large
portion of the burden of the disease falls upon the minority
populations of the U.S., demonstrated by the fact that the
prevalence rates of diabetes are higher among Native Americans,
African Americans, Hispanic Americans, and Asian
and Pacific Island Americans when compared with non-
Hispanic whites (99). The long-term complications associated
with type 2 diabetes are both microvascular and macrovascular
in nature and include the following: retinopathy,
peripheral and autonomic neuropathy, nephropathy, peripheral
vascular disease, atherosclerotic cardiovascular and cerebrovascular
disease, hypertension, and susceptibility to
infections and periodontal disease (for an extensive description
of the complications associated with diabetes, the
reader is referred to Diabetes in America, 1995; 80,81).
The diagnosis and classification of diabetes have been
revised by the Expert Committee on the Diagnosis and
Classification of Diabetes Mellitus (59). The new classification
system emphasizes etiology and pathogenesis rather
than modalities of treatment. Diabetes is divided into four
major categories depending on etiology: type 1, type 2,
gestational, and other specific types. In type 1 diabetes, the
final common pathway is beta cell destruction by autoimmune
processes, which leads to insulin deficiency. Type 2
diabetes is characterized by varying degrees of insulin resistance
and relative insulin deficiency. Gestational diabetes
is defined as any degree of glucose intolerance with onset or
first recognition during pregnancy. The final category includes
diabetes due to specific genetic defects, medications,
and other diseases (59).
Guidelines for diagnosing diabetes have also been revised
and are much simpler than the previous scheme. The new
diagnostic criteria reflect more closely the prevalence of
microvascular complications specific for diabetes. One of
three criteria must be met for the diagnosis of diabetes: 1) a
fasting plasma glucose $ 126 mgzdL21; 2) symptoms of
diabetes such as polyuria, polydipsia and unexplained
weight loss plus a casual plasma glucose of 200 mgzdL21 or
more; and 3) 2-h plasma glucose $ 200 mgzdL21 during an
oral glucose tolerance test using 75 g of glucose. If there is
no acute metabolic decompensation, these criteria should be
confirmed on a different day (59).
Both genetic and environmental factors have been implicated
in the etiology of type 2 diabetes. There is a strong
genetic predisposition for this type of diabetes although the
exact genetic defects are not currently well defined (59).
Among the risk markers for the disease are older age,
obesity, minority ethnicity, family history, and lower socioeconomic
status (81). Along with overall obesity, fat distribution
(specifically, intra-abdominal fat distribution) predicts
type 2 diabetes (22,23,51,72,78,101,132,138,169,177).
Lifestyle factors that are implicated in the development of
type 2 diabetes are physical inactivity and more inconsis-
1345
POSITION STAND
tently, diet, and parity (169). Type 2 diabetes is a dynamic
disease in which individuals often become more insulin
deficient with time.
The pathophysiology of type 2 diabetes appears to involve
defects in both insulin action (insulin resistance) and
secretion (insulin deficiency) (149). Insulin resistance is
manifested by decreased insulin-mediated storage of glucose
as glycogen in the liver and muscle. At the cellular
level muscle glucose transporters (GLUT 4) may not be
normally translocated from cytoplasm to plasma membrane
although GLUT 4 protein and mRNA are normal (47,105).
Insulin receptor substrate (IRS) phosphorylation is an important
intermediary step in this process and may play a
central role (91). IRS-1 is a cytoplasmic protein with multiple
phosphorylation sites. After stimulation by insulin, it
serves as a docking protein that facilitates phosphorylation
of other intracellular proteins such as phosphatidylinositol
kinase (PI 3-kinase). PI 3-kinase may be an important effector
in the pathway by which GLUT 4 transporters are
inserted into the plasma membrane. Abnormalities in IRS-1
(91) or other insulin receptor substrates have been postulated
to be involved in insulin resistance. A separate defect
in glycogen synthesis may also exist (170) and be found in
nondiabetic relatives of persons with type 2 diabetes (188).
These defects in insulin action may be either genetic or
acquired through such factors as abdominal obesity. Chronic
hyperglycemia and increased free fatty acid (FFA) levels
may also contribute to acquired insulin resistance (147).
Each of these may cause decreased muscle glucose transport
and phosphorylation and are reversible (11). Insulin secretion
is abnormal in type 2 diabetes with the first phase of
insulin release generally being absent (145). Hyperglycemia
alone may further inhibit insulin secretion. This concept has
been termed glucose toxicity (213). Elevated products of fat
metabolism may also impair beta cell function.
The goal of treatment in type 2 diabetes is to achieve and
maintain near-normal blood glucose levels and optimal lipid
levels, in order to prevent or delay the microvascular, macrovascular,
and neural complications (52). Because exercise
improves insulin sensitivity (diminishes resistance), it is
a logical treatment modality. Exercise also modifies lipid
abnormalities and hypertension. It, along with medical nutrition
therapy, is an important component of obesity management.
Use of oral antidiabetic agents and/or insulin may
also be required to achieve normal glucose levels. These
oral medications and insulin are described in reference 2.
The aim of this position stand is to provide appropriate
background and recommendations for safe and effective
participation in physical activity by those with type 2 diabetes.
Additionally, physical activity is an underutilized
mode of therapy for type 2 diabetes, often due to lack of
understanding. This position stand provides a breadth and
depth of information that should facilitate understanding
and use of exercise in the management of type 2 diabetes.
For information about a wider range of specific sports and
diabetes, the reader is referred to the Health Professionals
Guide to Diabetes and Exercise (6).
Acute Effects of Exercise/Physical Activity
Physical activity is one of the principal therapies to
acutely lower blood glucose in type 2 diabetes due to its
synergistic action with insulin in insulin-sensitive tissues.
Abnormal insulin secretion and peripheral insulin resistance
(38) are primary factors that influence the acute effects of
physical activity on metabolic responses in those with type
2 diabetes. In addition, oxygen delivery to peripheral tissues
in type 2 diabetic individuals may be impaired during acute
bouts of graded exercise (82,102), as the rate of oxygen
consumption during submaximal and maximal work loads is
significantly lower than age- and activity-matched persons
without diabetes (94,151). Hence, functional capacity of
those with type 2 diabetes is frequently lower than agematched
nondiabetic counterparts (102,161,164). Acute
bouts of physical activity can favorably change abnormal
blood glucose and insulin resistance (113).
Glucose levels. Most obese, type 2 diabetic individuals
exhibit decreases in blood glucose after mild-to-moderate
exercise (85,107,131,186). The magnitude of decrease in
blood glucose is related to the duration and intensity of
physical activity (138) and is further modified by preexercise
glucose level and novelty of the activity.
Blood glucose reduction during physical activity is attributed
to an attenuation of hepatic glucose production,
whereas muscle glucose utilization increases normally
(29,102,131). Reduced hepatic glucose production may include
a negative feedback mechanism associated with sustained
insulin levels during exercise and elevated glucose
levels before activity.
Mild-to-moderate intensity exercise lowers blood glucose,
and this effect is sustained into the postexercise period
(85,131). Thus, mild-to-moderate intensity exercise is recommended
to facilitate glucose reductions in those with
type 2 diabetes. Blood glucose response to moderate exercise
in lean, type 2 diabetic individuals is highly variable
(87) and is not as predictable as in their obese counterparts.
Such variability during exercise is related to impaired feedback
control of hepatic glucose regulation and may be due
to a defective nonpancreatic glucoregulatory mechanism.
During short-term, high-intensity exercise, blood glucose
frequently increases in obese, type 2 diabetic individuals
who have hyperinsulinemia and remains elevated for about
1 h postexercise due to counter-regulatory hormone increase
(102).
Insulin resistance. Insulin resistance is a frequent abnormality
in type 2 diabetes (8,10). Insulin resistance reduces
insulin-mediated glucose uptake in those with early
stage type 2 diabetes by 35–40% of the level of glucose
uptake in individuals who do not have diabetes (38,46).
Insulin-mediated glucose uptake occurs primarily in skeletal
muscle and is directly related to the amount of muscle mass,
and inversely associated with fat mass (212). Some studies
(35,38,48), but not all (154), show that exercise increases
peripheral and splanchnic insulin sensitivity in those with
type 2 diabetes. This increased sensitivity persists from 12
up to 24 h postexercise. Moreover, the insulin dose-response
1346 Official Journal of the American College of Sports Medicine http://www.msse.org
curve is not fully normalized by an acute bout of activity
(35). There is no consensus regarding the effects of high
intensity exercise on insulin sensitivity in persons with type
2 diabetes, as some (33) have found improved insulin sensitivity
regardless of exercise intensity, whereas others (154)
have shown insulin resistance for up to 60 min after highintensity
work. Such disparate findings of exercise intensity
on insulin sensitivity can be partly explained by: 1) the
different methods of assessing insulin sensitivity, including
oral glucose challenge or insulin clamp technique; 2) the
intensity of exercise administered; and/or 3) the heterogeneity
of those with type 2 diabetes and their respective
responses to acute exercise. The effect of an acute bout of
exercise on insulin action is lost within a few days (79,164),
and the benefit of a single bout of physical activity is
short-lived for persons with type 2 diabetes. Thus, regular
activity performed at a low-to-moderate intensity is recommended
to lessen insulin resistance in type 2 diabetic
individuals.
Most studies examining the effects of acute exercise on
insulin sensitivity and glucose disposal in type 2 diabetes
have included relatively small sample sizes and have not
adequately distinguished the impact of physical activity
among therapies, including medical nutrition therapy alone,
oral antidiabetic medications, and/or insulin. Further research
is needed regarding exercise-related changes in insulin
sensitivity in the heterogeneous make-up of type 2
diabetes to more clearly understand the acute impact of
physical activity on insulin resistance.
Chronic Effects of Exercise/Physical Activity
Genetic factors associated with insulin resistance and
impaired glucose tolerance may result in low initial fitness
and a reduced capacity to adapt to physical training
(21,43,53). There is evidence of a reduced functional capacity
in healthy individuals at high risk for development of
type 2 diabetes even before the appearance of glucose intolerance
(136). It is well established that patients with a
diagnosis of type 2 diabetes have low V˙ O2max values when
compared with healthy age-matched controls (58,94,151).
Specific pathogenic mechanisms such as hyperglycemia,
low capillary density, alterations in oxygen delivery, increased
blood viscosity, or presence of vascular and neuropathic
complications may also contribute to the decreased
V˙
O2max.
Regular physical activity promotes beneficial physiological
changes in those with type 2 diabetes (84,97,98,
107,113,135,163,187,195,196,198,200,215), including lower
resting and submaximal heart rate; increased stroke volume
and cardiac output; enhanced oxygen extraction; and lower
resting and exercise blood pressure (27,41,61,65,106,113,135).
Those with type 2 diabetes are at increased risk for several
cardiovascular risk factors, including hypertension and dyslipidemia
(7,10,58,93,158,167). Thus, therapy to control glucose
levels and reduce long-term complications should focus on
behavioral interventions that include a physically active lifestyle.
Hypertension. Essential hypertension is a common cardiovascular
risk factor occurring in over 60% of persons
with type 2 diabetes (10). The efficacy of physical activity
to favorably alter blood pressure is well-documented in
those without diabetes (5,187) and is commonly stated as an
outcome of physical activity participation in those with type
2 diabetes. Some studies (110,165), but not all (171), have
observed that regular physical activity lowers blood pressure
in persons with type 2 diabetes. To date, there is a
paucity of studies specifically investigating the effect of
physical activity on lowering blood pressure in persons with
type 2 diabetes. Further research to more clearly identify
blood pressure response to exercise in those with type 2
diabetes is needed.
Metabolic control: glucose control and insulin resistance.
Aerobic power is inversely related to modest, favorable
changes in glycosylated hemoglobin (e.g., HbA1 or HbA1c)
and/or glucose tolerance (29,82,110,112,152,157,161,162,186,
190). In these studies, duration of physical training ranged from
6 wk to 12 months, and improved glucose tolerance was shown
in early stage type 2 diabetes with as little as seven consecutive
days of training (154). Some studies (131,171,192) have shown
that mild-to-moderate physical training ranging from 12 wk up
to 2 yr did not improve glucose control in type 2 diabetic
subjects. Also, older diabetic individuals (e.g., over 55 yr) may
not evince the same exercise-induced blood glucose changes as
usually occur in younger counterparts (215). Favorable
changes in glucose tolerance usually deteriorate within 72 h of
the last exercise bout in those with type 2 diabetes (164) and are
a reflection of the last individual exercise bout, rather than
training per se (107,108,154). Hence, regular physical activity
is recommended for persons with type 2 diabetes to sustain
glucose-lowering effects.
A strong inverse relationship has been shown to exist
between physical fitness and mortality due to all causes
(26,27). Furthermore, major reductions in all-cause death
rates are apparent with only modest increases in V˙ O2max,
especially for those at the lowest levels of fitness. This
finding is especially important in type 2 diabetes asV˙ O2max
values of 6 METs (metabolic equivalent) and less are common
in these patients. Kohl et al. (106) demonstrated a
similar inverse relationship between fitness and mortality
across levels of glycemic control. Although risk of death
increases with less-favorable glycemic status, the adverse
impact of hyperglycemia on mortality appears to be reduced
with increased fitness.
In some people with type 2 diabetes, insulin-mediated
glucose disposal is improved after a period of physical
training (29,84,108,112,152,186). After physical training,
insulin sensitivity of both skeletal muscle and adipose tissue
can improve with or without a change in body composition
(84,108,124,189). This effect is transient and, as observed in
glucose tolerance, deteriorates within 72 h (164). Consequently,
regular physical activity is imperative for those
with type 2 diabetes to sustain improved insulin sensitivity.
Lipids and lipoproteins. Increased aerobic power of
people with type 2 diabetes is related to a less atherogenic
lipid profile, which may lessen the accelerated rate of ath-
EXERCISE AND TYPE 2 DIABETES Medicine & Science in Sports & ExerciseT 1347
erosclerosis and related mortality rate (106). Some studies
found that after physical training, those with type 2 diabetes
showed desirable changes in triglycerides (18,19,154,
155,156,157,205), total cholesterol (18,19,154,157,192),
and high-density lipoprotein (HDL)-cholesterol:total cholesterol
ratio (19,192), whereas others studies have found no
change (114,171). A single study found that physical training
significantly increased HDL-cholesterol and lowered
low-density lipoprotein (LDL)-cholesterol in exercising versus
control type 2 diabetic subjects (156). Also, some research
(18,19,206) suggests that favorable triglyceride and
cholesterol reduction in persons with type 2 diabetes is best
achieved through weight loss, even though training-induced
changes in blood lipids are independent of body weight
(215).
Intensity, duration, and frequency of exercise training
may influence lipid and lipoprotein changes. The inclusion
of nutrition advice, counseling, or behavioral intervention to
aid in lowering dietary saturated fat and body weight can
also influence the magnitude of lipid changes in those with
type 2 diabetes participating in physical training. Clearly,
more research that examines nutrition therapy and exerciseinduced
lipid alterations in type 2 diabetes is needed.
Weight loss/maintenance. Exercise and medical nutrition
therapy are essential for the initial treatment of type
2 diabetes and, when drug therapy is needed, for maintaining
efficacy of drug therapy. Moderate weight loss (;10–
15% or 4.5–9.1 kg) can assist in achieving metabolic goals
(74,202,209). Nutrition therapy and regular exercise combined
are more effective than either alone in achieving
moderate weight reduction and thereby improving metabolic
control (153,176,205,206). Weight loss leads to a
decrease in insulin resistance and may be most beneficial
early in the progression of type 2 diabetes when insulin
secretion is still adequate.
Exercise also results in preferential mobilization of upper
body fat (134). Visceral adipose tissue correlates significantly
with hyperinsulinemia and is negatively associated
with insulin sensitivity (25). Visceral fat represents a significant
source of FFAs which may be oxidized in preference
to glucose, resulting in hyperglycemia (140). Loss of
visceral fat may be an important benefit of exercise as
reduction of abdominal obesity leads to significant improvement
in metabolic indices (213). Furthermore, abdominal
obesity is a major risk factor for cardiovascular disease (24)
and the development of type 2 diabetes (113).
Persons with type 2 diabetes, however, are often not able
to exercise at a level that is required for significant weight
loss to occur and body weight and body fat losses with
exercise alone are often reported to be small. To improve
body weight and body composition, regular exercise at an
intensity of about 50% V˙ O2max, five times or more per
week, for about 1 h per session sustained for years would
appear to be necessary (34). Therefore, it is important for
health professionals to guard against unrealistic expectations
of quick or easy weight loss in individuals beginning
an exercise program.
Although the mechanism is still unclear, exercise seems
to be effective in promoting long-term weight loss and has
consistently been one of the strongest predictors of longterm
weight control (116). Exercise is, therefore, a valuable
adjunct measure along with food changes in the long-term
management of weight. Furthermore, individuals who exercise
may adhere better to nutritional advice. Physical
activity may improve mood and self-esteem and as a result
contribute to better control of food intake (164).
Psychological issues. The impact of diabetes on lifestyle
and health, and the psychosocial adjustments to diabetes
required by those with type 2 diabetes in later life may
have important consequences on perceived stress, glucose
control, and psychological health (73,117,182). Diabetic
complications are more prevalent in those with long-standing
type 2 diabetes (8) and require increased psychosocial
adjustments (210). Diabetic complications contribute to perceived
stress of disease management (185) and affective
disorders, especially depression (66). Thus, therapy for
those with type 2 diabetes should include social or family
support systems that assist in facilitating adherence to a
recommended treatment plan.
There are presumed physiological and psychological benefits
of regular exercise in those without diabetes; reduced
stress response to psychosocial stimuli (96), lessened sympathetic
nervous system activation to cognitive stress (174),
favorable reductions in depression (191), heightened selfesteem
(173), and reduced emotional perturbations associated
with life’s stressful events (116,127). Such benefits in
type 2 diabetes have received little attention, yet appear to
have importance relative to augmenting perceived health
and sense of self, and lessening the negative impact of stress
and depression on disease management.
Given that diabetes management is emotionally stressful,
particularly later in life for those with type 2 diabetes, and
that this stress can influence glycemic control (116), regular
physical activity can play a role in reducing stress, enhancing
psychological well-being, and augmenting the quality of
life for people with type 2 diabetes (191). Few studies have
examined the effect of regular physical activity on various
psychosocial, psychological, and stress-related outcomes in
type 2 diabetes. The favorable changes associated with
regular exercise in those without diabetes are presumed to
occur in those with type 2 diabetes; however, future research
is necessary to elucidate the efficacy of physical activity to
evince such favorable psychological alterations.
The Role of Physical Activity in the Prevention of
Type 2 Diabetes
Studies reviewed above examine the acute and chronic
effects of physical activity on carbohydrate metabolism and
glucose tolerance and provide the physiological reasons
why a relationship between physical activity and glucose
tolerance is biologically plausible. Through the years, from
early observations to randomized clinical trials, the existence
of a potential relationship between physical activity
1348 Official Journal of the American College of Sports Medicine http://www.msse.org
and type 2 diabetes has also been supported by the epidemiology
literature. Relationships between physical activity
and type 2 diabetes were suggested early by the fact that
societies which had abandoned traditional lifestyles (which
typically had included large amounts of habitual physical
activity) had experienced major increases in type 2 diabetes
(204). Indirect evidence of this phenomenon was also provided
by the observation that groups of subjects who migrated
to a more modern environment had more diabetes
than their ethnic counterparts who remained in their native
land (75,95,148) and that rural dwellers had a lower prevalence
of diabetes than their urban counterparts
(45,100,216,217). In these studies, differences in physical
activity were suggested as partial explanations for the differences
in diabetes prevalence.
Cross-sectional and retrospective epidemiological studies
have provided more direct evidence that physical inactivity
is significantly associated with glucose intolerance within
populations. Groups of subjects with type 2 diabetes were
found to be less active currently (50,100,109,183,184) and
reported less physical activity over their lifetime (109) than
individuals without diabetes. In addition, cross-sectional
studies that have examined the relationship between physical
activity and glucose intolerance in individuals without
type 2 diabetes generally showed that blood glucose values
after an oral glucose tolerance test (39,51,109,115,141,
168,199), as well as insulin values (51,60,115,128,150,199),
were significantly higher in the less active compared to the
more active individuals. More recently, the fact that a sedentary
lifestyle may play a role in the development of type
2 diabetes has been demonstrated in prospective studies of
male college alumni (80), female college alumni (64), registered
nurses (120), male physicians (119), and middleaged
British men from the general population (142) and
perhaps in metabolically obese, normal-weight individuals
(those with hyperinsulinemia, insulin-resistance, hypertriglyceridemia,
and premature coronary heart disease who are
not obese) (159).
Similar to measures of physical activity, poor physical
fitness, as determined by maximal oxygen uptake or as
estimated by vital capacity, also appears to play a role in the
development of type 2 diabetes (54,55). In addition, support
that physical fitness may provide some protection against
mortality in men at all levels of glucose tolerance (from
those with normal blood glucose to those with type 2 diabetes)
was demonstrated in middle-aged men (106).
Physical activity was a major part of the intervention
strategy of a feasibility trial of diabetes prevention in 47–49
yr old men from Malmo, Sweden. Of those with impaired
glucose intolerance at baseline, at least twice as many of
those who did not take part in the treatment program had
developed diabetes at the 5-yr follow-up compared with
those that participated (55). A major limitation to this study
was that participants were not randomly assigned to the
intervention treatment groups.
The most promising of the studies, however, was a 6-yr
clinical trial of diabetes prevention in Da Qing, China (139).
At the beginning of the study, 577 individuals with impaired
glucose tolerance were identified from a city-wide health
screening and randomized by clinic into one of four groups:
exercise only, diet only, diet plus exercise, and a control
group. Individuals assigned to the exercise group were encouraged
to increase their daily leisure physical activity by
one unit, which in most cases was comparable to a 20-min
brisk walk daily. The cumulative incidence of diabetes at 6
yr was significantly lower in the exercise intervention
groups compared with the control group (exercise 5 41%,
exercise plus diet 5 46%, diet 5 44%, control 5 68%) and
remained significant even after adjusting for baseline differences
in body mass index and fasting glucose (139).
A randomized, multicenter clinical trial of type 2 diabetes
prevention that incorporates physical activity as one of the
possible treatments is currently underway in the United
States (49). In this clinical trial, physical activity is combined
with dietary modification to comprise the lifestyle
intervention.
Recommended Physical Activity Program for
People with Type 2 Diabetes
Physical activity programs for those with type 2 diabetes
without significant complications or limitations should include
appropriate endurance and resistance exercise for developing
and maintaining cardiorespiratory fitness, body
composition, and muscular strength and endurance. In order
to facilitate weight management and achieve health-related
benefits, it is strongly recommended that individuals with
type 2 diabetes expend a minimum cumulative total of 1000
kcalzwk21 (27,61) in aerobic activity. The addition of a
well-rounded resistance training program should be effective
in improving muscular strength and endurance as well
as in improving body composition by increasing or maintaining
fat-free weight. Appropriate frequency, intensity,
duration, and mode(s) of physical activity should be identified
for persons with type 2 diabetes.
Frequency. Those with type 2 diabetes should engage
in at least three nonconsecutive days and up to five physical
activity sessions each week to improve cardiorespiratory
endurance and achieve desirable caloric expenditure (4).
Recently, the U.S. Surgeon General (187) recommended
that physical activity should be performed most, if not all
days of the week, to effect favorable health-related benefits,
such as weight loss, blood pressure reduction, and favorable
lipid and lipoprotein changes. Given that the acute effect of
a single exercise bout on blood glucose levels is less than
72 h (90,196), those with type 2 diabetes must participate in
regular physical activity to lower blood glucose. Those with
type 2 diabetes taking insulin may prefer to participate in
daily physical activity, in order to lessen the difficulty of
balancing caloric needs with insulin dosage. Moreover,
obese diabetic individuals may need to participate in daily
physical activity to maximize caloric expenditure for effective
weight management (4).
Intensity. For the majority of persons with type 2 diabetes,
low-to-moderate intensity physical activity (of 40–
70% V˙ O2max) is recommended to achieve cardiorespiratory
EXERCISE AND TYPE 2 DIABETES Medicine & Science in Sports & ExerciseT 1349
and metabolic improvements. Favorable metabolic changes
(e.g., blood glucose reduction, and increased insulin sensitivity
and metabolic clearance rate) usually occur after regular
physical activity performed at a low-to-moderate intensity
(31,140,206,211), whereas others (29,110,164) have
shown favorable metabolic changes with higher-intensity
exercise (e.g., 70–90% ofV˙ O2max) as well. Although a low
intensity level is adequate to facilitate metabolic changes
(202), it may not meet the recommended minimum threshold
of exercise intensity (e.g., $ 50% of V˙ O2max) for improving
cardiorespiratory endurance (4). Most importantly,
implementing low-to-moderate intensity activities for persons
with type 2 diabetes minimizes the risks and maximizes
the health benefits associated with physical activity for this
population. Moreover, the lower intensity activity affords a
more comfortable level of exertion and enhances the likelihood
of adherence, while lessening the likelihood of musculoskeletal
injury and foot trauma, particularly when
weight-bearing activity is recommended (68).
Monitoring the intensity of physical activity in persons
with type 2 diabetes may require the use of heart rate or
ratings of perceived exertion (RPE) (4). Although a percentage
of heart rate reserve (50–85%) or maximal heart rate
(60–90%) is commonly used to identify exercise intensity
for nondiabetic individuals, those with type 2 diabetes may
develop autonomic neuropathy (192), which affects the
heart rate response to exercise. Consequently, using heart
rate as the only means to monitor intensity may be unsuitable
for some with type 2 diabetes. A more appropriate
adjunct to gauge the intensity of physical activity may be to
use the RPE scale, especially in those who do not require
specific heart rate limits (4). It is imperative that those using
this scale become familiar with its use (e.g., matching description
of level of perceived effort with a corresponding
number) for proper implementation.
Duration. The duration of physical activity for persons
with type 2 diabetes is directly related to the caloric expenditure
requirements and inversely related to the intensity.
Initially, those with type 2 diabetes should engage in physical
activity for 10–15 min each session (68). Ideally, it is
recommended that the time of the physical activity session
be increased to at least 30 min to achieve the recommended
energy expenditure (4). Also, physical activity can be divided
into three 10-min sessions, whereby 30 min of physical
activity is accumulated in a single day to account for the
necessary energy expenditure (27). As stated earlier, when
weight loss is a primary goal, the intensity needs to be
low-to-moderate (50%V˙ O2max) and the duration needs to be
incrementally increased to approximately 60 min (30).
Mode. The recommended types of physical activities for
persons with type 2 diabetes are those that afford greater
control of intensity, have little interindividual variability in
energy expenditure, are easily maintained, and require little
skill (4). Combined with personal interests and goals, the
mode of physical activity is important to aid in motivating
the person with type 2 diabetes to begin physical activity, as
well as to sustain a life-long physical activity habit. The
mode of physical activity dictates that the level of energy
expended and/or improvement in cardiorespiratory endurance
be directly influenced by the amount of muscle mass
used over the time of activity, as well as the rhythmic and
aerobic nature of the activity. For those with type 2 diabetes,
it is important to identify a mode of physical activity that
can safely and effectively maximize caloric expenditure.
Walking is the most commonly performed mode of activity
for those with diabetes (63) and is the most convenient
low-impact mode of physical activity. However, because of
complications or coexisting conditions such as peripheral
neuropathy or degenerative arthritis, those with type 2 diabetes
may require alternative modes that are non-weightbearing
activities (e.g., stationary cycling, swimming,
aquatic activities) or alternate between weight bearing and
non-weight-bearing activities (4).
Resistance training has the potential to improve muscular
strength and endurance, enhance flexibility, enhance body
composition, and decrease risk factors for cardiovascular
disease (143,175,179,182). In nondiabetic subjects, resistance
training has resulted in improvements in glucose tolerance
and insulin sensitivity (86,130,160). Resistance
training appears to prevent loss of, and may even increase,
muscle mass during and after energy restriction (15,34,67).
Treuth et al. (185) were able to demonstrate that intraabdominal
obesity was reduced after 16 wk of moderateintensity
resistance training. There are limited data on the
use of resistance training in individuals with type 2 diabetes
(56,62), but results appear to be consistent with the findings
in nondiabetic subjects mentioned above.
It is recommended that resistance training at least 2
dzwk21 should be included as part of a well-rounded exercise
program for persons with type 2 diabetes whenever
possible. A minimum of 8–10 exercises involving the major
muscle groups should be performed with a minimum of one
set of 10–15 repetitions to near fatigue. Increased intensity
of exercise, additional sets, or combinations of volume and
intensity may produce greater benefits and may be appropriate
for certain individuals. More detailed information for
developing the resistance exercise training plan for people
with diabetes is available (83). All persons with type 2
diabetes should be carefully screened before beginning this
type of training and should receive proper supervision and
monitoring. Caution should be used in cases of advanced
retinal and cardiovascular complications. Modifications
such as lowering the intensity of lifting, preventing exercise
to the point of exhaustion, and eliminating the amount of
sustained gripping or isometric contractions should be considered
in these patients.
Rate of progression. The rate of increasing physical
activity for those with type 2 diabetes is dependent upon
several factors, including age, functional capacity, medical
and clinical status, and personal preferences and goals
(4,68,201). Moreover, initial changes in progression should
focus on the frequency and duration of physical activity,
rather than intensity, in order to provide a safe activity level
that can be performed without undue effort and to increase
the likelihood of sustaining the activity habit (4,208). Initially,
it is recommended that those with type 2 diabetes
1350 Official Journal of the American College of Sports Medicine http://www.msse.org
engage in physical activity at a comfortable level (RPE
10–12) for about 10–15 min at a very low intensity at least
3 times per week and preferably 5 times per week (187,207).
Duration of physical activity should be gradually increased
to accommodate the functional capacity and clinical status
of the person with type 2 diabetes. Given that older age and
obesity are common elements of type 2 diabetes (8,10), a
longer period of time may be necessary for the older and/or
obese person to adapt to a recommended physical activity
program (4,200). After the desired duration of activity is
achieved, any increase in intensity should be small and
approached with caution to minimize the risk of undue
fatigue, musculoskeletal injuries, and/or relapse.
Limitations. The feasibility and efficacy of using physical
activity as treatment for type 2 diabetes has been questioned
for many years (27). Motivation is difficult and
drop-out rates are often very high. Those with type 2 diabetes
often find endurance exercise to be uncomfortable.
Insulin-resistant subjects, as well as those with type 2 diabetes,
have an increased number of type IIb muscle fibers,
a low percentage of type I fibers, and a low capillary density
(28,29,31,122,137). These muscle fiber composition abnormalities
may affect tolerance for aerobic activity. The intensity
of exercise at the anaerobic threshold is also lower in
subjects with type 2 diabetes (19,32). Care should be taken
to keep exercise intensity at a comfortable level in the initial
periods of training and should progress very cautiously as
tolerance for activity improves.
Risks and Complications of Exercise
Acute glycemic responses. Moderate-intensity exercise
increases glucose uptake by 2–3 mgzkg21zmin21 above
usual requirements (70-kg person: 8.4 –12.6 gzh21 of exercise).
During high-intensity exercise, glucose uptake increases
by 5–6 mgzkg21zmin21; however, exercise of this
intensity cannot usually be sustained for long intervals
(201).
Adequate and appropriate nutrition is important for any
person engaging in physical activity. Fatigue can result from
deficiencies of oxygen, fluids, or fuel, which can occur
separately or in combination. Carbohydrate is needed during
events lasting longer than 60–90 min (44,197) as well as
after exercise to replenish muscle glycogen stores (89).
Fluid intake is essential. For exercise lasting up to 1 h, plain
water is usually the best beverage, but for exercise lasting
longer, water and extra carbohydrate are needed. Six to 8%
carbohydrate solutions are absorbed better and cause less
stomach distress than regular soft drinks and fruit juices,
which are 13–14% carbohydrate solutions (111).
Hypoglycemic reactions in connection with exercise in
persons with type 2 diabetes are rare, occurring mainly in
persons being treated with sulfonylurea oral medications
and/or insulin and participating in unusually strenuous or
prolonged exercise. Instruction on appropriate treatment of
hypoglycemia in those with type 2 diabetes who use these
medications is necessary. Blood glucose regulation during
exercise in the person with type 2 diabetes controlled by
nutrition therapy alone is not significantly different from
that in persons without diabetes. During mild-to-moderate
exercise, elevated blood glucose concentrations fall toward
normal but do not reach hypoglycemic levels. There is no
need for supplementary food intake before, during, or after
exercise, except when exercise is exceptionally vigorous
and of long duration as explained above. In this case, extra
food may be beneficial just as it is in the person who does
not have diabetes.
To minimize the occurrence of low blood glucose, it is
imperative to understand the relationship of the exercise
bout to the: (a) time when medications were taken (e.g., time
of oral antidiabetic medications, or time and site of insulin
injection); (b) antecedent and postexercise nutrition; and (c)
last blood glucose assessment. The timing of insulin injection
should be at least 1 h before the onset of exercise and
preferably in a nonexercising or nonactive area. (Use of a
nonexercising area does not guarantee prevention of low
blood glucose.) Depending on the duration and intensity of
exercise, the insulin dose may need to be modified. Insulin
dose adjustments must be made on an individual basis and
should be done in consultation with appropriate members of
the health care team.
Self blood glucose monitoring is recommended for those
with type 2 diabetes who engage in physical activity, especially
during the initial activity sessions (4,68). Moreover,
glucose monitoring is appropriate before and after an exercise
bout. Given the knowledge and understanding of glucose
levels, persons with type 2 diabetes, in consultation
with their health care professional, can take appropriate
action by reducing medications before exercise or increasing
carbohydrate consumption (~15 gzh) before or after
exercise to reduce the likelihood of hypoglycemia. Adjustment
to medications is preferable over increasing caloric
intake to prevent hypoglycemia in those trying to reduce
body weight.
Long-term complications. Although macrovascular
and microvascular complications are prevalent in type 2
diabetes (10,13), their existence is not an absolute contraindication
for physical activity. However, the risk of exacerbating
specific complications and provoking musculoskeletal
injuries in persons with type 2 diabetes is increased with
physical exertion (57,198). Thus, there are physical activity
precautions for all persons with type 2 diabetes, and limitations
for those who have diabetic complications (215).
Before commencing exercise, those with type 2 diabetes
should have a thorough physical exam to assess the presence
of macro- and/or microvascular complications, and obtain
physician approval to ensure that a safe and effective individualized
activity program is developed (4,68). Initially,
medical approval should evaluate glucose control (e.g.,
HbA1c), physical limitations with respect to joint immobility
common to diabetes, prescribed medications, and special
considerations with reference to the type and severity of
complications (see Table 1). Given the age of the person and
duration of diabetes, the physician may recommend that a
stress test be performed before safely participating in an
exercise program. For those with type 2 diabetes that are
EXERCISE AND TYPE 2 DIABETES Medicine & Science in Sports & ExerciseT 1351
$ 35 yr of age, it is recommended that a stress test be
conducted before participating in most physical activity (4).
The rationale for recommending a stress test electrocardiogram
on persons who meet this age criterion is to assess
cardiovascular and respiratory systems, as the risk for macrovascular
disease is increased in type 2 diabetes (9).
Moreover, the stress test electrocardiography will identify
target heart rate limits within which the person with or
without autonomic neuropathy can safely exercise. Additionally,
physical exertion may induce a recognizable hypertensive
response in some with diabetes (28). Exerciseinduced
hypertension can be identified during a stress test
and avert abnormal blood pressure excursions during normal
physical activity by identifying appropriate physical
activities (e.g., intensity, or selection of activity). For additional
information on the chronic complications of diabetes
and exercise, the reader is referred to the Health Professional’s
Guide to Diabetes and Exercise (6).
Vascular disease. Diabetes is a major risk factor for
the development of cardiovascular disease. The risk of myocardial
infarction is 50% greater in diabetic men and 150%
greater in diabetic women (203). The propensity for arrhythmias
during exercise and the ischemic response to exercise
should be evaluated. Moderate intensity activity (60–80%
of maximum heart rate, 50–74%V˙ O2max) is usually recommended
for those with known coronary artery disease without
ischemia or significant arrhythmias (14,144). In those
with angina, the target heart rate should be 10 beats or more
below the ischemic threshold (3). In patients without angina,
the ischemic threshold should be determined by an exercise
electrocardiogram.
Autonomic neuropathy interferes with heart rate regulation
by depressing maximal heart rate and blood pressure,
and increasing resting heart rate (92). Early warning signs of
ischemia may also be absent in those with autonomic neuropathy.
There is increased risk for exercise-induced hypotension
after strenuous activity in persons with autonomic
neuropathy (218). Moreover, persons with autonomic dysfunction
exhibit a lower fitness level and fatigue at relatively
low workloads (193,194). Consequently, physical activity
for these persons should focus upon low-level daily activities,
where mild changes in heart rate and blood pressure can
be accommodated (69). Any physical activity program for
persons with autonomic neuropathy should be viewed with
caution and should have physician approval. Moreover, it is
recommended that type 2 diabetic individuals with autonomic
neuropathy undergo a diagnostic stress test to rule out
the presence of cardiac function abnormalities and identify
safe limits of physical activity (217).
Although weight-bearing activity is preferred (4), type 2
diabetic individuals with peripheral vascular disease (PVD)
who have claudication may choose to perform low- or
non-weight-bearing activity (e.g., swimming, aquacize, stationary
cycling) or alternate between different types of
weight-bearing versus non-weight-bearing activities. Physical
activity must be performed to pain tolerance with intermittent
rest during each session of activity (4). Moreover,
peripheral neuropathy in the presence of PVD may preclude
the use of weight-bearing activities, due to the possibility of
foot trauma (193).
Peripheral neuropathy. This form of neuropathy affects
the extremities, especially the lower legs and feet
(70,71,162), and results in loss of distal sensation that can
lead to musculoskeletal injury or to infection. Non-weightbearing
activities should be performed by persons with
peripheral neuropathy in order to mitigate irritation and/or
trauma to the lower legs and feet (69,193). As a pragmatic
recommendation, proper footwear for all weight-bearing
activities of daily living is very important to minimize the
likelihood for undetected sores, which can evolve into an
infection if unnoticed. The feet should be examined daily by
the person with diabetes and at each physician visit.
Nephropathy. Increased blood pressure is a common
precursor and is related to worsening kidney disease (69);
however, it remains to be proven whether exercise-induced
blood pressure changes exacerbate the progression of nephropathy.
Although few studies have examined exerciseinduced
microalbuminuria in persons with type 2 diabetes
(133), physical activity may assist in controlling factors
(e.g., blood glucose and blood pressure) related to the progression
of nephropathy in those with type 2 diabetes
(88,103). Persons with nephropathy should avoid activities
which cause the systolic blood pressure to rise to 180–200
mm Hg (e.g., performing Valsalva maneuver, high-intensity
aerobic or strength exercises), as increases in systemic pressure
could potentially worsen the progression of this disease.
Those with later stages of renal disease should participate
in lower intensity physical activities (; 50%V˙ O2max)
with physician approval, as cardiorespiratory and healthrelated
benefits are accrued at this lower level of training. It
is recommended that exercise testing be conducted to identify
safe intensity limits for those with type 2 diabetes who
have advanced nephropathy (32).
Retinopathy. Although exercise increases systemic and
retinal blood pressures, there is no evidence that physical
activity acutely worsens the retinopathy present in diabetes
(195). Bernbaum and associates (20) found that type 1 and
type 2 diabetic individuals with proliferative retinopathy
who engaged in a low-intensity training program improved
cardiovascular function by 15%. Precautions were taken to
limit systolic blood pressure to 20–30 mm Hg above baseline
during each training session. Thus, in a well-supervised
environment, low-intensity aerobic activity can be safely
performed by persons with retinopathy (194,216). Those
with type 2 diabetes should be evaluated to determine the
TABLE 1. Evaluation before starting an exercise program.
Evaluate glycemic control
Subject may need modification of medication or carbohydrate ingestion if
hypoglycemia is a problem
Severe hyperglycemia may be worsened with intense exercise
Are complications present?
Is the subject known to have cardiovascular disease or is he/she at high risk?
Is the subject at risk for injury due to peripheral neuropathy?
Is diabetic renal disease present? High intensity aerobic or resistance exercise
may worsen progression.
Does the subject have retinopathy which will be worsened by activities which
increase ocular pressure, e.g., resistance training?
1352 Official Journal of the American College of Sports Medicine http://www.msse.org
degree of retinopathy. If retinopathy is present, they need to
be cautioned about engaging in activities that cause blood
pressure to increase dramatically, such as head-down or
jarring activities or those with arms overhead (194,195,216).
Adoption and Maintenance of Exercise by
Persons with Diabetes
In spite of substantial evidence showing health benefits of
long-term exercise for persons with diabetes (195), it is
rarely incorporated as an integral part of therapy (64). Moreover,
adherence to prescribed exercise programs is frequently
poor (63,129).
Little is known about factors likely to affect exercise
adoption and maintenance. Two theoretical models are useful
for understanding these factors: the transtheoretical
model (i.e., stages of change theory) (146) and self-efficacy
theory (17). The transtheoretical model postulates that persons
are at different cognitive stages with regard to their
readiness to adopt and maintain a particular behavior, such
as exercise, ranging from precontemplation and contemplation
to preparation, action, and maintenance. The implication
of this stage-based model is that interventions designed
to encourage adoption of an exercise regimen must be
responsive to the stage of readiness that the individual is
currently in and focus effort on moving the individual
through the stages (121).
Self-efficacy theory postulates that adoption of exercise is
a function of judgment concerning ability to do exercise in
relation to the probable benefits and costs associated with
the activity (16,17). In this context, research has demonstrated
that persons with previous exercise experience
(42,179), and particularly previous success (125,126), have
substantially higher exercise efficacy expectations. In addition,
physical status may be of equal importance to developing
exercise efficacy expectations among older adults
who are more likely to have type 2 diabetes and also suffer
from more physical limitations generally associated with
age (125,126,146).
Outcome expectations are viewed as an important element
of models of health behavior and may contribute
significantly to one’s motivations to adopt a particular behavior.
A person’s confidence for adopting a behavior is
influenced in part by the extent to which belief of rewards
are associated with that behavior (1). Thus, outcome expectations
will have important implications for the form of
information and education delivered by health care providers
(172). This is supported by research which found that
having a physician discuss the benefits of physical activity
was a strong predictor of exercise adoption among African-
American women (118).
Factors influencing the contemplation stage.
Several factors should be addressed to help motivate the
person in the contemplation stage to initiate an exercise
program (123). First, the program must be viewed by the
person as desirable and intrinsically reinforcing. Second, the
activities recommended must be perceived as realistic and
feasible. Third, strategies for avoiding the potential negative
consequences of exercise, particularly those associated with
diabetes must be taught.
The failure of persons with diabetes to engage in regular
exercise is due, in part, to their outcome expectations. Many
are not familiar with the benefits of exercise on their diabetes.
Even when the benefits are known, health care professionals
often describe exercise to their patients using a
negative reinforcement paradigm, i.e., exercise is done to
avoid the onset of punishment in the form of complications,
not as an intrinsically enjoyable activity with health benefits.
Oftentimes, attempts at exercise have resulted in physical
discomfort, injury, or hypoglycemia, thus “demonstrating”
that the costs outweigh the potential long-term benefits.
To engender a better outcome expectation, the rationale
for the prescription of exercise should include discussion of
the social, psychological, and general health benefits in the
population as a whole, as well as particular benefits in
persons with diabetes. Social benefits include participation
of family members, peers, and participation in organized,
community-based activities (123). Psychological benefits
include reduction in stress, anxiety, and depression and
increased feelings of well-being (166). Health benefits include
improvements in glucose regulation, weight control,
lipid profiles, hypertension, and increased work capacity
(36,37,194,198).
To help address efficacy expectations, several key points
should be emphasized:
l To benefit diabetes control, exercise needs to be part of
a lifelong management program that starts gradually and
works up to higher intensity.
l To sustain an exercise program, help the patient select
one that reflects their goals, desires, and the availability of
appropriate support.
l Teach the person with diabetes how to perform the
selected activity so that he/she avoids discomfort, injury,
and problems with his/her diabetes.
l Assure those with diabetes that they do not have to
figure out how to set up an exercise program alone. There
are health care professionals who can help them accomplish
these goals.
Factors influencing the action stage. An important
component to increasing exercise adoption is providing patients
with specific exercise prescriptions. Frequently, the
recommendation to exercise is a generic prescription with
no specific instructions about what to do or how to do it. As
a result, most persons with diabetes do not have a clear idea
about what type of exercise will work best for their particular
situation. Moreover, they are not given much guidance
concerning how to adjust their diabetes regimen to safely
exercise. As a result, they often choose activities without
any reflection as to their suitability or safety. Discussing
patients’ answers to two simple questions can help them to
more critically consider factors that can help or hinder their
selection of an exercise method they are likely to enjoy.
These questions are:
What are your goals for exercise? Finding out patients’
goals for exercising will help them identify a method to
achieve those goals (180). Their rationale may not reflect
EXERCISE AND TYPE 2 DIABETES Medicine & Science in Sports & ExerciseT 1353
what the health care professional feels is most important but
may result in achieving the same endpoint.
What types of physical activity are you doing or think you
would like to do? This question is designed to help guide
patients in selecting an activity they are motivated to do. If
they do not have preferences, ask them to indicate their
preference between the following options: a) long or short
duration; b) high versus low intensity; c) exercising by
themselves or with others; d) exercising at home or at a
facility; e) exercising indoors versus outdoors; and f) a
competitive or cooperative sport.
Their responses to these types of preference trade-offs
will help them to more critically consider what is truly
reinforcing to them. It will also help to provide suggestions
as the suitability of a given activity and how they may best
adapt their diabetes regimen to its demands.
The Ease of Access and Ease of Performance
Index. Once the person with diabetes has narrowed down
the possibilities, or even selected a specific exercise method,
the reasonableness of the activity given their personal situation
should be considered by reviewing the “Ease of Access”
and Ease of Performance“ index (123). These are
self-assessments of how realistic the activity is for them
given their life style.
Ease of Access Index. The Ease of Access addresses
the question “how easily can I engage in my activity of
choice where I live?” Many people have a tendency to begin
an exercise program only to find that it’s simply too difficult
to participate on a regular basis for a variety of reasons that
were either ignored, rationalized, or simply not considered
before the program was begun. To determine their “ease of
access” index for a given activity, ask the person to consider
the following questions:
l Does it require special facilities and are these facilities
available?
l Does it require special equipment and is this equipment
available and affordable?
l Does it require special training or instruction and is this
instruction readily available, scheduled at convenient times,
easy to get to, and affordable?
l Does it require others to do it and can these partners
always be found?
l Is it seasonal, and what can be done other times of the
year?
Ease of Performance Index. If the exercise activity
has an acceptable ease of access index, encourage evaluation
in terms of its ease of performance index. The ease of
performance index is an assessment of how suitable the
activity is in terms of the person’s physical attributes and
life style. To determine the ease of performance index, have
the person consider the following questions:
l Does the activity suit their physical attributes?
l Can he/she realistically integrate the chosen activity
into his/her current lifestyle?
l Can he/she afford any costs associated with it?
l Does he/she have a good support network if needed for
the activity?
Factors influencing the maintenance stage. There
are several factors that health care professionals can use to
help persons with diabetes maintain an exercise program.
These include:
1. Appropriate exercise and equipment to avoid injury.
The individual with diabetes should engage in a proper
warm-up and follow a gradual build-up training schedule.
Equally important is the use of proper equipment, especially
footwear.
2. Set realistic exercise goals. Exercise goals should be
precisely defined and realistically attainable. Goals should
be defined by exercise behavior (e.g., walk 30 min three
times per week) rather than by a desired outcome (e.g., lose
20 pounds). Smaller, step-wise goals for which success and
progress can be observed should be encouraged.
3. Set an exercise schedule in advance and stick to it.
Long-term habits are developed through practice. Moreover,
a regular schedule makes diabetes regimen adjustments easier
to establish thereby improving glycemic control.
4. Use an exercise partner. An exercise partner can help
encourage and motivate an individual to maintain a training
schedule. In addition, they may be of assistance in the event
of a hypoglycemic episode.
5. Encourage self-rewards. Progressive rewards for
reaching exercise goals can increase motivation to stay with
an exercise program.
6. Identify alternative exercise activities to reduce boredom.
Individuals who become bored with a single activity
should be encouraged to select alternative activities that will
help them remain active. The goal is to do some form of
physical activity.
7. Understand the difference between failure and backsliding.
For some individuals, any deviation from a schedule
or not meeting the expectations is viewed as failure. It is
important to help such individuals understand and accept off
days as part of any long-term exercise program. When off
days do occur, the concept of a “backslide,” i.e., a temporary
state, should be reinforced, and return to the regular schedule
encouraged.
CONCLUSION
Physical activity affords significant acute and chronic
benefits for those with type 2 diabetes. The benefits of
chronic physical activity are more numerous than those of
acute physical activity, emphasizing the need for regular
participation by those with type 2 diabetes and those at risk
for this form of diabetes.
Unfortunately, physical activity is underutilized in the
management of type 2 diabetes. This may be due to lack of
understanding and/or motivation on the part of the person
with diabetes and lack of clear recommendations, encouragement,
and follow-up by health care professionals. Several
factors including muscle fiber composition, low capillary
density, obesity, and older age require that physical
activity be initiated at lower intensity/duration and be increased
gradually to reduce risks and contribute to maintenance
of physical activity by those with type 2 diabetes.
1354 Official Journal of the American College of Sports Medicine http://www.msse.org
Attention to the patient’s stage of readiness and factors that
will encourage adoption and maintenance of regular physical
activity are extremely important for successful use of
physical activity as a therapeutic intervention. Health care
professionals must address physical activity more seriously
in this patient population because most people with type 2
diabetes have the potential to derive benefits from regular,
moderate levels of physical activity.
ACKNOWLEDGMENT
This pronouncement was reviewed for the American
College of Sports Medicine by members-at-large, the
Pronouncements Committee, and by Paula Harper, R.N.,
C.D.E.; Edward S. Horton, M.D.; Neil Ruderman, M.D.,
D.Phil.; Stephen Schneider, M.D.; and Bernard Zinman,
M.D., FACP, FRCP.
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