Exercise Management
Chapter 24
Exercise Management
Diabetes (video) is a chronic metabolic
disease characterized by an absolute or
relative deficiency of insulin that results in
hyperglycemia.
Clinical Overview (hyperlink)
Clinical Criterion




Fasting blood glucose > 125 mg/dl
Random blood glucose > 200 mg/dl with hyperglycemic symptoms
Two hour glucose > 200 mg/dl during an oral glucose tolerance test
(OGTT)
Exercise Management
Blood glucose measurements that are bound
to hemoglobin (HbA1c) [video] provides an
average blood glucose level over a prolonged
period – 60 -90 days
Individuals with diabetes are at risk for
developing microvascular complications,
including retinopathy and nephropathy;
macrovascular disease; and various
neuropathies (both autonomic and peripheral).
Neuropathy can also enable silent ischemia.

Exercise Management
Type 1 Diabetes - In type 1 diabetes mellitus, there is
an absolute deficiency of insulin caused by a marked
reduction in insulin secreting beta cells of the
pancreas.
Type 1 diabetics are prone to develop ketoacidosis
when hypoinsulinemia results in hyperglycemia.
The cause of type 1 diabetes is thought to involve
an autoimmune response directed at the beta cells
which are eventually destroyed.
 The factors that trigger the autoimmune response
have not been specifically identified but may include
viruses or toxins.
Exercise Management
Type 2 Diabetes - Individuals with Type 2
diabetes are considered to have a relative
insulin deficiency because they may have
elevated, reduced, or normal insulin levels but
still present with hyperglycemia.
 Thus, Type 2 diabetics present with
hyperglycemia regardless of blood insulin
status
Exercise Management
In type 2 diabetes, peripheral tissue insulin
resistance and defective insulin secretion
occur.
 With insulin resistance, glucose does not
readily enter the insulin-sensitive tissues (primarily
muscle and adipose tissue), and hyperglycemia occurs.
 The hyperglycemia causes the beta cells of
the pancreas to secrete more insulin in an
attempt to maintain a normal blood glucose
concentration.

Exercise Management

The additional endogenous insulin is usually
ineffective in lowering blood glucose and may further
contribute to insulin resistance.
 Eventually the beta cells may become exhausted
and fail to produce adequate amounts of insulin.
 The mechanisms underlying insulin resistance
remain unclear but probably involve defects in the
binding of insulin to its receptor and in post-receptor
events such as glucose transport.
Obesity significantly increases insulin resistance,
thus the majority of patients with type 2 diabetes are
obese.
Exercise Management
Those
with type 2 diabetes do not develop
ketoacidosis except under conditions of
unusual stress (e.g., trauma).
 Family history is a risk factor for type 2
diabetes, and type 2 diabetes typically occurs
after age 40.
Exercise Management
Gestational Diabetes - Gestational diabetes
occurs during pregnancy because of the
contra-insulin effects of pregnancy (pregnancy
hormones effect insulin uptake and production).
Risk factors for the development of
gestational diabetes include family history of
gestational diabetes, previous delivery of a
large birth weight baby, and obesity
 Approximately 50% of the women who
develop gestational diabetes develop type 2
diabetes later in life.

Exercise Management
Impaired Glucose Tolerance
and Impaired Fasting Glucose
Impaired glucose tolerance (IGT) and impaired
fasting glucose (IFG) are intermediate
metabolic conditions between normoglycemia
clinical diabetes. (see link above)
Exercise Management
Effects on the Exercise Response
The effect of diabetes on a single exercise session is
dependent on several factors, including:
 use and type of medication to lower blood glucose
(insulin or oral hypoglycemic agents)


timing of medication administration
blood glucose level prior to exercise timing,
amount, and type of previous food intake
 presence and severity of diabetic complications;
 use of other medication secondary to diabetic
complications,
 the intensity, duration, and type of exercise.
Exercise Management
Effects of Exercise Training
 Possible improvement in blood glucose control with
type 2 diabetes, but is not considered a component of
treatment in type 1 diabetes to lower blood glucose
(must < 250 mg/dl for type 1 patient to exercise, no ketones), but may
improve CV health
 Improved insulin sensitivity / lower medication
requirement.
 Reduction in body fat.
CV benefits
Prevention of Type 2 diabetes, especially those with
IGT, hx of Gestational Diabetes , or family hx.
Exercise Management
Diabetes Management and Meds
 Insulin allows glucose to enter the cells of
insulin sensitive tissue. There are several
different types of insulin available
pharmaceutically (injected or via insulin pump) that vary in
onset, peak, duration, and source (see table 21.1 on
page 185).
Oral agents for type 2 diabetes are
medications that help the pancreas secrete
more insulin, alter carbohydrate absorption,
reduce liver glycogenolysis, and/or increase
insulin sensitivity (see table 24.2 and 24.3 on pages 186-87).

Exercise Management
The most significant effect of both insulin and
oral hypoglycemic agents on exercise testing
and exercise training is their ability to cause
hypoglycemia. Attention to timing of
medication, food intake, and blood glucose
level before and after exercise is necessary.
 If exercise is of long duration (i.e., > 60 min),
blood glucose should be periodically tested
during exercise.

Exercise Management
Recommendations for Exercise Testing
Exercise testing using protocols for populations at risk
for coronary artery disease (CAD) is recommended in
people who:
have type 1 diabetes and are over the age of 30
 have had type 1 diabetes longer than 15 years
 have type 2 diabetes and are over age 35
 have either type 1 or type 2 diabetes and one or more of
the other CAD risk factors;
 have suspected or known CAD
 have any microvascular or neurological diabetic
complications.
 See Table 24.4, p.187

Exercise Management
Recommendations for Exercise Testing
Diabetic patients who do not meet any of the
pervious criteria may be tested with
protocols for the general healthy population.
In these individuals, the primary objective is
to:
1)
2)
Identify the presence and extent of CAD
Determine the appropriate intensity range for
aerobic exercise testing.
Diabetic patients who present chronotropic impairment during
exercise are at a increased risk of MI and all cause
mortality.
Exercise Management
Recommendations for Exercise Programming
(see Table 24.5, pp.188-189)

The exercise prescription for people with diabetes
must be individualized according to medication
schedule, presence and severity of diabetic
complications, and goals and expected benefits of the
exercise program.
 Food intake with exercise must be considered for
type 1 individuals. These patients must have food
supplies on hand during the exercise session. The
amount of carbohydrate ingestion is dependent on
the length of the exercise session.
Exercise Management
Recommendations for Exercise Programming
Exercise is contraindicated if:
 there is active retinal hemorrhage or there has
been
recent therapy for retinopathy (e.g., laser treatment)
 illness or infection is present
 blood glucose is above 250 mg/dl and ketones are
present (blood glucose should be lowered before
initiation of exercise) or
blood glucose is < 70 mg/dl because the risk of
hypoglycemia is great (if postexercise blood glucose is < 100
mg/dl, carbohydrate should be eaten and blood glucose allowed to increase
before the initiation of exercise)
Exercise Management
Recommendations for Exercise Programming
Exercise precautions include the following:
 keeping a source of rapidly acting carbohydrate
available during exercise
 consuming adequate fluids before, during, and
after exercise
 practicing good foot care by wearing proper shoes
and cotton socks, and inspecting feet after exercise;
carrying medical identification.
End of Presentation