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578 Exercise and Physical Activity in Diabetes Mellitus

Metabolic and Hormonal Effects of Exercise related to the exercise. In moderate aerobic exercise
in Diabetes: it increases or remain unchanged
During the past 30 years, much has been learned *Hypoglycemia occurs if hyperinsulinemia exists
about the metabolic and hormonal adaptations that during moderate intensity aerobic exercise, exercise
occur during physical exercise. These information’s in prolonged (> 30 to 60 min) and if no extra snacks
can be used to develop strategies for the manage- are taken before or during moderate intensity exer-
ment of persons with diabetes who wish to partici- cise.
pate in sports or other various vigorous recreational * Normoglycemia remains unchanged if exercise is
activities. During exercise several cardio vascular brief and mild to moderate in intensity and appropri-
humoral and metabolic responses occur in a highly ate snacks are taken before and during moderate in
integrated fashion to ensure the delivery of oxygen intensity exercise.
and metabolic fuels to working muscle and remove
metabolic end products. *Hypoglycemia occurs if hypoinsulinemia exists
during exercise is very intense and excessive carbo-
Type 1 Diabetes: hydrate taken before or during exercise.
The transition from rest to moderate exercise char-
acterized by the activation of sympathetic and hor- TYPE 2 DIABETES:
monal systems that stimulate the use of the glucose The metabolic and humoral effects of exercise in
stored in the muscle and liver and the release of free T DM resulting in cardio vascular risk reduction has
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fatty acids by the adipose tissue. Rate of glucose ox- been dealt in detail in this chapter. Exercise induced
idation during moderate intensity exercise estimated stimulation of such uptake involves many factors.
to be 2 mg/kg/min in adults and these leads to a They include increased post-receptor insulin sig-
fast decreased in blood glucose concentration due naling, increased glucose transporter protein and
to impairment in the glucagon counter regulatory re- mRNA, increased activity of hexokinase and gly-
sponse. Even with a sufficient glucose and adrena- cogen synthase, decreased release and increased
line response to physical exercise in T DM, elevated clearance of free fatty acids, increased muscle glu-
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levels of exogenous insulin may directly or indirectly cose delivery as a result of increased muscle capil-
inhibit glucagon secretion due to its antagonist effect lary density, changes in muscle composition favoring
and reduce lipolysis and proteolysis. The huge rate increased glucose disposal and changes in adipose
of carbohydrate oxidation during physical exercise in tissue mass and distribution. Decrease in visceral fat
T DM could be one of the factors leading to hypogly- result in decreases in tumor necrosis factor (TNF) and
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cemia. Several factors affect the blood glucose levels free fatty acids, leading to decreased insulin resis-
during exercise including an energy balance inade- tance. Exercise training in T DM has been shown to
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quate to demand of exercise, added to an excessive produce anti- atherosclerotic lipid profile and other
amount of insulin administered to the sub cutaneous cardiovascular risk factors. Resistance training has
areas involved in the exercise, increased the rates of also been shown to improve insulin sensitivity and
insulin absorption promoting hypoglycemia. There is glucose metabolism.
also increase in insulin sensitivity by 40% for 48hrs.
Studies also reflect two main defenses against by Physical Activity, Exercise Screening,
hypoglycemia are impaired in T DM. As these indi- Programming and Remcommendations in
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viduals are unable to decrease the levels of circu- Diabetes:
lating insulin and have impaired glucagon response.
Even the adrenaline response may be less robust In many patients with both T DM and T DM, adequate
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and due to the signs and symptoms of hypoglyce- glycemic control can often be achieved by dietary
mia related to autonomic regulation are impaired. It changes, regular physical activity, structured exer-
has been shown that repeated hypoglycemia T DM, cise and weight control. Specific recommendations
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induces what is termed as hypoglycemia associated and guidelines for exercise in diabetes have been
autonomic failure (HAAF). published by the American Diabetes Association
(AHA) and the American College of Sports Medicine
So the metabolic and hormonal responses of T DM (ACSM) . Advice to be tailored to individuals taking
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patients to exercise depend on the intensity and du- into account of their choices, personal goals, levels
ration of exercise, the patient blood sugar control of fitness, contra indications and available resources.
level, dose and site of pre-exercise insulin injection,
timing of the pervious insulin injection and the meal

GCDC 2017