Type 2 diabetes is a complex disease characterized by a failure of insulin to remove sugar (glucose) from the bloodstream. Under healthy conditions, insulin interacts with body cell mechanisms that permit the passage of glucose out of blood circulation and into tissues. Impairment of this process, called insulin resistance, results in hyperglycemia (elevated blood sugar), type 2 diabetes and other health problems. Substantial scholarly research supports the role of exercise as an effective and necessary strategy for managing a myriad of variables associated with type 2 diabetes.
Diminished Hyperglycemia
An acute bout of physical activity helps insulin clear glucose from circulation for 12 to 48 hours after exercise. Regular episodes of physical activity sustain this effect, minimizing hyperglycemic consequences over time. Improvements in blood sugar control result from adaptations of skeletal muscles to physical training.
Skeletal muscles use glucose to power physical activity. Taxing muscles increases their need for glucose. Regular training prompts increased glucose storage capacity, generation of new blood vessels within muscles, and improvements in insulin's ability to push glucose into cells (insulin sensitivity). Additionally, the research of Dr. John Hawley published in the January 2008 issue of the "Journal of Applied Physiology" suggests that exercise directly extracts glucose from the blood without the help of insulin, underscoring the importance of exercise in persons with depressed pancreatic insulin production.
Reduced Insulin Demand
Hyperglycemia causes excessive insulin production by the pancreas. Supplemental skeletal muscle absorption of glucose resulting from chronic exercise reduces the demand for circulating insulin, sparing the insulin-producing cells of the pancreas from the eventual fatigue associated with type 2 diabetes.
Management of Obesity
Obesity worsens insulin resistance. Hyperglycemia promotes lipid (fat) accumulation in skeletal muscles, while simultaneously suppressing fat metabolism by cells. Regular caloric expenditure driven by chronic exercise reduces lipid deposition. A 2006 study published in "Essays In Biochemistry" suggests that, "accumulation of excess lipid within muscle cells can be avoided by exercise, which improves the capacity for fatty acid oxidation (metabolism)."
Prolonged blood sugar control through obesity management relies heavily on physical activity. The position of the American College of Sports Medicine pertaining to weight management recommends at least 150 minutes of exercise weekly to reduce body fat, and at least 200 minutes weekly for maintenance of lost weight.
Minimized Complications
A poor blood lipid profile frequently accompanies insulin resistance and diabetes. Elevation of blood fats, hazardous lipoproteins (LDL), inflammatory chemicals and free radicals significantly increase cardiovascular complications over time. Exercise minimizes lipid dysfunction and promotes metabolism of fat. The position of the American College of Sports Medicine on exercise and type 2 diabetes reports that improved insulin sensitivity reduces blood viscosity (thickness), diminishing the risk of neuropathy and microvascular (small vessel) complications associated with body tissues receiving reduced oxygen flow.
Less recognized complications of diabetes include depression and other psychological issues. Exercise combats arousal and anxiety related to diabetes and its consequences. Physical activity also heightens self-esteem and lessens the psychological burden of long-term disease management associated with type 2 diabetes and its complications.
References
- "Medicine & Science in Sports & Exercise"; ACSM Position Stand on Exercise and Type 2 Diabetes; July 2000
- "Diabetes Care"; Effects of Exercise Training Intensity on Pancreatic Beta Cell Function; Slentz et al.; Oct. 2009
- "Medicine & Science in Sport and Exercise"; ACSM Position Stand, Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults, Feb. 2009
