Download Helping Your Patients Become Active

Lifestyle and Behavior
Helping Your Patients Become Active
Jacqueline Shahar, MEd, RCEP, CDE
Exercise and physical activity are
major contributors to the prevention
and management of diabetes. Dating
back as far as 1000 AD, Greek physicians prescribed exercise as a way
to improve health. Dr. Elliot P. Joslin
encouraged his patients to become
more physically active; one method
was to get a dog from a local shelter and walk it a few times a day.1
In the present era of medicine, exercise is a cornerstone of diabetes care.
It is prescribed to prevent diabetes,
improve diabetes control, and promote weight loss. People with type 2
and some people with type 1 diabetes are often sedentary and in most
cases are overweight or obese. These
struggles usually have a negative
impact on diabetes control. People
with diabetes benefit greatly from
consistent physical activity because
activity helps in managing glucose
levels, losing weight, preventing and
controlling comorbidities and complications, and improving quality of
life.2
Thus, health care providers
should and often do encourage
their patients to become physically
active. However, clinicians’ lack of
knowledge with regard to exercise
often presents a challenge. Exercise
advice must include proper guidance
about the appropriate type, duration, and frequency of exercise and
about blood glucose management
with exercise. This article discusses
the basic physiology and glucose
metabolism with exercise, barriers
to becoming physically active and
solutions to those barriers, options
for exercise with the presence of diabetes complications and orthopedic
issues, and guidance for blood glucose management with exercise.
Glucose is the energy source for
the muscles. Type 2 diabetes, with
its associated insulin resistance, obesity, hyperinsulinemia, and hypertension, interferes with the glucose supply to the muscles. In type 1 diabetes, lack of insulin production by the
β-cells in the pancreas is associated
with hyperglycemia, polyuria, polydipsia, polyphagia, blurred vision,
and weight loss. An inadequate supply of glucose because of either type
1 or type 2 diabetes results in muscles having difficulty performing
movements.3
Metabolic response to exercise
can be influenced by several factors,
such as general health, age, nutritional status, exercise capacity, duration and frequency of exercise, metabolic control, and response to insulin or diabetes medications. Exercise
has an immediate effect on the body,
including cardiovascular, metabolic,
and hormonal changes. At the first
stage of exercise, oxygen demand
increases as a result of an increase
in cardiac output, accompanied by
an increase in respiration and blood
flow to the muscles. Initially, muscle glycogen stores are utilized as a
source of energy until, after several
minutes, the liver releases stored glycogen into the bloodstream. After
~ 20–30 minutes of exercise, muscles begin to use stored fat (free fatty
acids) as a source of energy. In addition, hormonal changes also occur
in response to exercise. Insulin secretion is reduced, and counterregulatory hormone levels (epinephrine,
norepinephrine, cortisol, growth
hormone, glucagon) increase, signaling the liver to produce glucose.4
This relationship between hormones and blood glucose during
Diabetes Spectrum Volume 21, Number 1, 2008
exercise is important to maintain
a healthy blood glucose level. For
example, at the end of an exercise
session in which a person exercises
at a low to moderate intensity, blood
glucose decreases and continues
decreasing. With vigorous exercise,
such as resistance training or intense
aerobic training, metabolic demand
increases. This leads to an increase
in hepatic glucose production and
results in hyperglycemia. In people
with type 1 diabetes, the pancreas is
unable to regulate insulin based on
blood glucose levels. Thus, the risk
for hypoglycemia is increased, particularly for people who inject a high
dose of insulin around exercise time.
However, people who do not have
enough insulin circulating in their
bloodstream are at risk for hyperglycemia. In addition, hyperglycemia can also result from abnormal
glucose utilization. When the body
cells do not have an adequate supply
of glucose, the body begins to break
down fats as a source of energy.
Ketones are formed as an intermediate step in the breakdown of fats.
People with type 1 diabetes must be
particularly careful to avoid exercising and creating increased need for
energy by the muscles when glucose
levels are very high because this may
lead to ketoacidosis.4
After an exercise session, glucose from the bloodstream continues moving to the active muscles for
at least 24 hours to replenish muscle
and liver glycogen stores. Therefore,
there can be a delayed hypoglycemic
effect even hours after an exercise
session. Further, nocturnal hypoglycemia can occur if a person exercises
in the afternoon or evening.5
59
Lifestyle and Behavior
Exercise also has important
chronic effects. As patients increase
the duration and frequency of exercise, more of the protein carrier
GLUT 4, which helps increase glucose uptake by the muscles, becomes
available to transport glucose to
active muscles. Consequently, insulin
sensitivity increases, glycemic control improves, weight loss can occur,
and complications can be prevented.
Over time, exercise can also lead
to improvements in cardiovascular
function, mental health, and quality
of daily living.6,7
However, many people with diabetes face barriers to becoming
active, even when they understand
all the benefits of exercise. Such barriers often include fatigue, depression, fear of hyperglycemia or hypoglycemia, diabetes-related complications, and disliking exercise. Some
people may find that although they
have taken the first step to becoming active, staying active is difficult.
Some people with diabetes report
that changing eating habits, checking blood glucose, or taking medications is easier than finding the motivation to be physically active.
Some people with diabetes may
report that they “hate exercise” or
“are allergic to exercise.” So how do
patients get started exercising and
stay active? With the help of their
health care team, they must recognize their personal barriers and find
appropriate solutions. For example,
research shows that, among a general population, higher depression
scores are associated with a greater
number of risk factors, including
sedentariness.8 Depression, stress,
and anxiety are all common among
people with diabetes.3 With exercise,
many hormonal changes in the brain
occur that result in improvement of
mood and reduction of depression,
stress, and anxiety.9 Specifically, evidence supports the notion that exercise increases pleasant-feeling states
in the short term and that, in the
long term, exercise can be just as
beneficial for depressive symptoms
as medication.10,11 Thus, if one can
overcome depression-related barriers to exercise, depressive symptoms
will actually improve, and depres60
sion may no longer be a barrier to
continued exercise.
One tip for patients who report
diminished motivation to exercise is
to find fun and easy activities that
require minimal preparation, such
as walking outside or on a treadmill
or cycling on a stationary recumbent
bike while watching TV or listening
to music. Any physical activity that
a person finds enjoyable works at
the beginning; it does not necessarily need to be a structured exercise,
although structure can be added
later if necessary.
In addition, several more logistical barriers can be addressed. If time
is a barrier, suggest scheduling 10minute time slots for exercise. Exercise sessions can be split into two or
three shorter sessions a day, and the
same benefits can still be achieved.12
Splitting exercise sessions could
also work well for those who have
no energy and feel fatigue. Patients
may find that exercising at times
when energy levels are higher is easier. Over time, exercise will increase
energy levels, so this barrier can be
easily overcome if patients can just
get started.
Joining a health club may be an
option for some people who need a
place to exercise. However, others
cannot afford or are uncomfortable
working out in the neighborhood
gym. Borrowing fitness DVDs and
tapes from the public library and
exercising at home or investing in a
piece of exercise equipment could
increase the chance of maintaining an exercise program. Making
friends with people who are active
or exercising with family members and friends can help patients
to stay motivated and feel both supported and supportive. For example, in a 20-week behavioral weight
control program in which obese
patients with type 2 diabetes participated either alone or with their
spouses, women were more successful in losing weight with the added
social support from their spouses.
However, men were more successful
when participating in the program
independently.13
If a patient is worried about not
having the proper skills to exercise
or about getting injured during exerDiabetes Spectrum Volume 21, Number 1, 2008
cise, working with a personal trainer
or joining an exercise class could
be a helpful option.14 As patients
become active, these individualized
barriers may persist, and new solutions may be necessary.
Once patients are ready to begin
exercising, they should attain clearance to do so from a primary care
physician before starting. An ophthalmic examination with dilated
pupils should also be performed
before starting resistance training,
vigorous exercise, or any activity
that may increase pressure in the retina or suddenly improve glycemic
control.15
Caution should always be used
when prescribing exercise for
patients with diabetes complications
or orthopedic issues. For example,
health care professionals often recommend walking to their patients
because it is a weight-bearing activity that is relatively easy to perform
and does not require a lot of preparation or skills. However, people with diabetes may develop muscle-skeletal problems because of
their sedentary lifestyle, obesity, and
deconditioning that may limit their
ability to walk. Diabetes complications, such as peripheral neuropathy and Charcot foot, and additional medical problems, such as
arthritis, peripheral vascular disease,
and peripheral arterial disease, may
also limit activity. Therefore, walking may no longer be an easy activity and may, in fact, become very
challenging.
Appropriate recommendations
for safe and easy activities for people who are physically limited are
imperative. Participation in non–
weight-bearing activities is easier,
more comfortable, can be done for a
longer period of time, and does not
carry the same risks of injury or the
worsening of complications or other
medical problems. Examples of non–
weight-bearing activities that might
be good recommendations include
the use of a recumbent stationary
bike or arm ergometer, water exercise or swimming, and chair exercises using a DVD or tape.7
Understanding and being able to
explain the different types of exercise that are each necessary for
Lifestyle and Behavior
optimal health is important. The
American College of Sports Medicine (ACSM) and the American
Heart Association suggest performing aerobic, resistance, and stretching exercises. Aerobic exercise refers
to a continuous activity that elevates heart rate, increases breathing frequency, involves major muscle groups, and improves endurance.9 Resistance exercise refers to
an activity that is conducted against
force, whether external weight or
body weight, that targets major
muscle groups. Resistance training promotes weight loss by increasing muscle mass, which increases
metabolism. It also increases muscle strength, which improves quality of daily living, reduces the risk
of injury, and increases muscle mass
and muscle tone, which can improve
self-image. Finally, resistance training increases bone density, which
helps to prevent osteoporosis.16
Stretching exercise is performed at
the end of an exercise session and
loosens the muscles after contraction
and lessens the risk of muscle-skeletal injury.9
Recommendations for the frequency and duration for each type
of exercise should be clear to achieve
the maximum benefits. Every adult
should engage in aerobic exercise
that elevates breathing and heart
rate for at least 30 minutes, five days
of the week, to improve endurance.
To attain the maximum health benefit, improve diabetes control, and
maximize caloric expenditure, individuals should exercise daily at low
to moderate intensity for 60 minutes
or more. The activity can be accumulated throughout the day with
a minimum of 10 minutes or more
for each exercise bout. The ACSM
suggests that adults should perform
resistance training two or more days
of the week with at least 48 hours
between sessions. This includes 8–10
exercises that target major muscle
groups that can be performed in sets
of 8–12 repetitions. Stretching exercises should also be performed daily
when muscles are warmed up.2,12
For people with diabetes, resistance training can be particularly
beneficial. Research has shown that
resistance training improves hemoglobin A1c; reduces subcutaneous and intra-abdominal fat tissue;
increases fat free mass; reduces LDL
cholesterol, triglycerides, and total
cholesterol; and reduces waist circumference.17,18 Resistance training
in combination with aerobic exercise is beneficial in reducing risk factor indicators, improving exercise
capacity, and reducing weight.19,20
Clinicians, therefore, should
advise patients with diabetes to
engage in a combination of aerobic and resistance training. People
who are members of a health club
can use the resistance machines in a
gym; others can obtain home resistance machines. For people who prefer exercising at home but cannot
afford expensive equipment, free
weights or stretching (tubing) bands
can provide similar benefits.
No matter where patients choose
to exercise, proper form of exercises
is essential to prevent injury and
the exacerbation of diabetes complications. For patients with diabetes, blood glucose should be monitored and managed before, during,
and after exercise to prevent hypoglycemia or hyperglycemia. Keeping records of activity, blood glucose levels, and insulin or diabetes
medications doses is an important
tool for health care providers and
patients to use to prevent or address
hypoglycemia or hyperglycemia during exercise and physical activity.
This information is also useful when
a patient’s goal is weight loss.
As patients become more active
and lose weight, their insulin and
diabetes oral medications may
require adjustment. Reduction in
medication use could also be a great
motivator for patients to stay active
and continue improving their diabetes control. Table 1 offers strategies for blood glucose management
before, during, and after exercise.5
Exercise and physical activity are known to have acute and
chronic benefits for people with diabetes and should always be incorporated to improve glycemic control and promote weight loss. Prescribing an appropriate exercise plan
that takes into account patients’ diabetes complications and orthopedic issues is imperative. Health care
Table 1. Strategies for Prevention of Hypoglycemia and Hyperglycemia
Before, During, and After Exercise
Target Blood Glucose Before Starting
Physical Activity
Blood Glucose During Physical
Activity
Blood Glucose After Physical
Activity
If on insulin or combination of insulin
with oral medications:
≥ 110 mg/dl
Check blood glucose halfway
through activity.
Check blood glucose immediately
after exercise and several hours
after the end of a session.
If on oral medications:
≥ 90 mg/dl
If blood glucose is below target: snack
immediately on 15–30 g of carbohydrate
(4 oz of juice or a small piece of fruit)
Replace fluid loss adequately.
If exercising for < 1 hour, drink
8–10 oz of water every 15–20
minutes. If exercising > 1 hour,
dilute sports drink (15–45 g of
carbohydrate) with water.
Use supplemental carbohydrate
(sports drink, juice, fruit, or
glucose tablets) if blood glucose
is below target.
Diabetes Spectrum Volume 21, Number 1, 2008
Eat 15–30 g of carbohydrates if
blood glucose is below target.
and/or
Reduce insulin or oral medications to prevent hypoglycemia
response to exercise (Table 2).
61
Department
Lifestyle
andOR
Behavior
Feature Article / Title
Table 2. Medication Adjustments on Day of Exercise and Guidelines for When to Avoid Exercise
Type 1 Diabetes
Type 2 Diabetes
Reduce 30–50% of rapid-acting insulin at the meal
closest to activity time.
Reduce dose of oral diabetes medications (sulfonyurea,
meglitinide, nateglinide) on days of exercise.
Reduce basal rate by 30–50% before or after activity
based on blood glucose reading and experience with
hypoglycemia.
Reduce 30–50% of rapid-acting insulin at the meal
closest to activity time.
If blood glucose is > 250 mg/dl, check for ketones. If
ketone test is positive, avoid exercise.
If blood glucose is > 400 mg/dl and the patient is not
feeling well, avoid exercise.
professionals can help patients overcome barriers to exercise by providing them with an understanding of
glucose management during exercise
and helping them create an exercise routine that is unique to their
health status, age, current exercise
capacity, glycemic control, and personal goals. Providing these services
will help patients get on track to a
healthier, happier, more physically
active life.
Acknowledgments
The author thanks Ashley Leighton
for her assistance with this article.
References
1
Mullooly CA, Kemmis KL: Diabetes educators and the exercise prescription. Diabetes
Spectrum 18:108–113, 2005
2
American College of Sports Medicine:
ACSM’s position stand: exercise and type 2
diabetes. 2000 [article online]. Available from
http://www.ms-se.com/pt/pt-core/templatejournal/msse/media/0700.pdf
3
Beaser RS: Joslin’s Diabetes Deskbook: A
Guide for Primary Care Providers. Revised
Edition. Boston, Mass., Joslin Diabetes Center, 2003
Wasserman DH, Davis SN, Zinman B: Fuel
metabolism during exercise in health and diabetes. In Handbook of Exercise in Diabetes.
Ruderman N, Devlin JT, Schneider SH, Kriska A, Eds. Alexandria, Va., American Diabetes Association, 2002, p. 63–99
4
5
Steppel JH, Horton WS: Exercise in patients
with diabetes mellitus. In Joslin’s Diabetes
62
Mellitus. 14th ed. Philadelphia, Pa., Lippincott Williams & Wilkins, 2005, p. 649–657
obese type II diabetic patients. J Consult Clin
Psychol 59:156–162, 1991
Hamdy O, Goodyear L, Horton ES: Diet and
exercise in type 2 diabetes. Endocrinol Metab
Clin North Am 30:883–907, 2001
14
6
Mullooly CA, Chalmers KH: Diabetes management therapies: physical activity/exercise.
In A CORE Curriculum for Diabetes Education: Diabetes and Complications. 5th ed.
Franz MJ, Ed. Chicago, American Association of Diabetes Educators, 2003, p. 61–90
7
Rosal MC, Ockene JK, Ma Y, Herbert JR,
Merriam PA, Matthews CE, Ockene IS: Behavioral risk factors among members of a
health maintenance organization. Prev Med
33:586–594, 2001
8
Whaley MH, Brubaker PH, Otto RM; American College of Sports Medicine: ACSM’s
Guidelines for Exercise Testing and Prescription. 7th ed. Baltimore, Md., Lippincott Williams and Wilkins, 2006
9
Reboussin BA, Gauvin L, Rejeski WK: Contributions of acute bouts of vigorous physical activity to explaining diurnal variations in
feeling states in active, middle-aged women.
Health Psychol 19:365–375, 2000
10
Blumenthal JA, Babyak MA, Moore KA,
Craighead WE, Herman S, Khatri P, Waugh
R, Napolitano MA, Forman LM, Appelbaum
M, Doraiswamy M, Krishnan R: Effects of
exercise training on older patients with major depression. Arch Intern Med 159:2349–
2356, 1999
11
Haskell WL, Lee I, Pate RR, Powell KE,
Blair SN, Franklin BA, Macera CA, Heath
GW, Thompson PD: Physical activity and
public health: updated recommendations for
adults from the American College of Sports
Medicine and American Heart Association.
Med Sci Sports Exerc 39:1423–1434, 2007
12
Wing R, Marcus, MD, Epstein LH: A ‘family-based’ approach to the treatment of
13
Diabetes Spectrum Volume 21, Number 1, 2008
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Division of Nutrition and Physical Activity: Promoting Physical Activity: A
Guide for Community Action. Champaign,
Ill., Human Kinetics, 1999
15
American Diabetes Association: Standards
of medical care in diabetes—2007 [Position
Statement]. Diabetes Care 30 (Suppl. 1):S4–
S41, 2007
Frontera W, Bean J (Eds.): Strength and
Power Training: A Guide for Adults of All
Ages. Boston, Mass., Harvard Health Publications, 2005
16
Eves ND, Plotnikoff RC: Resistance training
and type 2 diabetes: considerations for implementation at the population level. Diabetes
Care 29:1933–1941, 2006
17
Sigal RJ, Kenny GP, Boule NG, Wells GA,
Prud’homme D, Fortier M, Reid RD, Tuloch
H, Coyle D, Phillips P, Jennings A: Effects of
aerobic training, resistance training, or both
on glycemic control in type 2 diabetes. Ann
Intern Med 147:357–369, 2007
18
Shahar JI: Exercise intervention in a comprehensive weight loss program improves
walking capacity in obese diabetic people.
Med Sci Sports Exerc 39:S41, 2007
19
Shahar JI, Hamdy O, Goebel-Fabri A, Grant
G, Capelson R, Carver C, Beaton J: A graded balanced exercise plan in weight management program improves walking capacity and
risk factor indicators in obese type 2 diabetes
population [Abstract]. Diabetes (Suppl. 1) 56:
A636, 2007
20
Jacqueline Shahar, MEd, RCEP,
CDE, is the manager of exercise
physiology at the Joslin Diabetes
Center in Boston, Mass.