Diabetes and Exercise

Benefits of Exercise for People With Diabetes
Exercise and Insulin Sensitivity
Aerobic Training
Strength Training
Safety Considerations
Exercise Trends  
Fitness and Insulin Resistance
Diabetes and Obesity

Benefits of Exercise for People With Diabetes

For many years exercise has been recommended as a treatment for diabetes, but with a minimal understanding of how and why it benefits diabetes 70 .  Over the past two decades, a myriad of research has been generated that overwhelmingly demonstrates and explains the therapeutic effects of physical activity in diabetes. There is no longer a question of whether exercise is beneficial when dealing with diabetes, the answer is yes. 12. 

Benefits of Exercise for People with Diabetes include: 31

• Lower blood sugar levels (feel better and reduce bodily damage)
• Reduce need for insulin (less medications)
• Protect against heart disease and stroke
• Prevent heart disease, the #1 killer of diabetics
• Strengthen bones (prevent osteoporosis)
• Tone and strengthen muscles (more energy!)
• Stress relief (stress elevated blood sugars)
• Improve quality of sleep (regular sleep important for sugar regulation)
• Improves quality of life!

Exercise and Insulin Sensitivity
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Exercise can increase strength and metabolic function of the skeletal muscle tissue, leading to improvements in glycemic control 21 . A 7 to 20-fold increase in insulin sensitivity is seen in exercising muscle vs. sedentary muscle 20 . 

Strength Training
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The magnificent thing about resistance training and diabetes is that it can be used by all individuals with diabetes regardless of metabolic disease state or previous athletic experience 59.  For some people with type 2 diabetes, aerobic exercise may not be completely safe due to advancing age, obesity, circulatory, and arthritic complications.  Fortunately for these people strength training offers a safe and effective alternative.

Benefits of Resistance Training include: 69

• Promotes favorable energy balance
• Reduced visceral fat deposition
• Increased basal metabolism
• Counter-act age-related muscle wasting
• Improves insulin sensitivity
• Improves glycemic control
• Increases muscle mass
• Increases muscle endurance
• Increases muscles strength
• Improves bone density
• Osteoarthritic symptoms
• Improves mobility
• Self-efficacy
• Lowers blood pressure
• Lowers blood lipids or fats
• Alleviates symptoms of anxiety
• Alleviates symptoms of depression
• Alleviates symptoms of insomnia

Importance of Strength Training For Mature Adults with Type 2 Diabetes:

Ordinary conditions in older adults with diabetes (particularly type 2) include: 23

• Increased body weight (subcutaneous fat deposits)
• Reduced muscular insulin sensitivity
• Altered theremogenesis
• Decreased neurological function  
• Decreased muscular function
• Decreased circulatory function

Unfortunately, up to a 50% decrease leg strength has also been found in diabetics compared to non-diabetics 5.   The decrease in muscular leg strength leads to decreased mobility, greater frailty, and greater incidence of falls 51.  Therefore, due to increased fat weight and decreased muscular function, older diabetics have an even greater necessity for strength development than non-diabetic older adults 35 .  Sarcopenia (the loss of muscle mass) and age related losses in strength can be safely and effectively countered through strength training 23.  Strength training 2-3 days/week at 50-70% of 1 repetition maximum (1RM) improves strength and mobility, therefore reducing loss of mobility in older adults with diabetes 7. 

Aerobic Training
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There is a significant correlation between muscle fiber type and glucose clearance rates with type 2a muscle fibers demonstrating a greater response to insulin than type 2b muscle fibers 39 . Elevated levels of fast-twitch glycolytic fibers (type 2b) and a decreased number of slow-twitch oxidative fibers (type 1) are associated with type 2 diabetes 8. Glut4, the major insulin-responsive glucose transporter that is predominantly restricted to striated muscle and adipose tissue, is found in larger amounts in slow muscle fibers types than in fast twitch muscle fibers 13.   Therefore aerobic or moderate intensity resistance training is recommended for improving insulin sensitivity.  Low to moderate intensity exercise over a long duration 30-60 minutes is recommended for people who are overweight or have type 2 diabetes 2. 

It is never too late to start Exercising
Research has now demonstrated that regular exercise results in lower mortality and morbidity, which holds true for those who do not begin until late in life 31.  Mature adults who have developed insulin resistance over the course of a lifetime due to low physical activity can reverse this process and increase insulin sensitivity simply by starting to exercise. 31 .

Safety Considerations 59
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1.  All people with diabetes who are interested in beginning an exercise program should undergo a complete medical history and physical examination to identify macrovascular, microvascular, and neurological complications.
2.  Be sure to carry medical identification that states diabetic status in case of emergency.
3.  It is best to exercise about 3 hours after the last meal.
4.  Avoid exercising during peak insulin action.
5.  To ensure safety, it is important to measure pre and post blood sugar levels because blood sugar levels may be lowered during and after exercise.
6.  Always carry a source of fast acting carbohydrate in case of a low blood sugar.
7.  Stay hydrated! drink water before, during, and after exercise
8.  If sick or if monitored blood sugar is above 300 and positive for ketones.

When prescribing an exercise regimen for people with diabetes it is important to consider the following factors: 59

• Choice of exercises
• Order of exercises
• Resistance in diabetics with and without cardiovascular disease
• Number of sets per exercise
• Length of the rest period