Diabetes is one of the leading causes of death and disability in the United States with type 2 
diabetes accounting for 90–95% of all diabetic cases (3). Based on national data from the Centers for Disease Control and Prevention, there are about 10.3 million diagnosed cases of diabetes in the United States with an estimated 5.4 million additional undiagnosed cases in the general population. Some of the long term complications associated with Type 2 diabetes are heart disease, kidney failure, blindness, nerve dysfunction, and more (for an extensive description of the complications associated with diabetes, the reader is referred to Diabetes in America, 1995; 80,81).
There are four different categories of diabetes; type 1, type 2, gestational, and other specific types. Type 1 diabetes is an autoimmune disease that destroys the beta cells in the pancreas resulting in insulin deficiency. Type 2 diabetes is a result in insulin sensitivity in the muscle at varies degrees an can result in insulin deficiency. Gestational diabetes is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. The final category includes diabetes due to specific genetic defects, medications, and other diseases (1).
Type 2 diabetes disrupts the body’s ability to utilize substrates (fuels) during both rest and during exercise. The body normally changes sugars and starches to a usable form called glucose. Glucose is carried via blood stream to various tissues, such as skeletal muscle, to produce energy for cells. For glucose to enter the skeletal muscle a hormone called insulin must be present. Insulin is created by beta cells in the pancreas. In type 2 diabetes the sensitivity of skeletal muscle to insulin is compromised and the glucose can not enter the cell resulting in abnormal levels of glucose in the blood. These abnormal levels of glucose can be detrimental to ones health over extended periods of time.
diabetes accounting for 90–95% of all diabetic cases (3). Based on national data from the Centers for Disease Control and Prevention, there are about 10.3 million diagnosed cases of diabetes in the United States with an estimated 5.4 million additional undiagnosed cases in the general population. Some of the long term complications associated with Type 2 diabetes are heart disease, kidney failure, blindness, nerve dysfunction, and more (for an extensive description of the complications associated with diabetes, the reader is referred to Diabetes in America, 1995; 80,81).There are four different categories of diabetes; type 1, type 2, gestational, and other specific types. Type 1 diabetes is an autoimmune disease that destroys the beta cells in the pancreas resulting in insulin deficiency. Type 2 diabetes is a result in insulin sensitivity in the muscle at varies degrees an can result in insulin deficiency. Gestational diabetes is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. The final category includes diabetes due to specific genetic defects, medications, and other diseases (1).
Type 2 diabetes disrupts the body’s ability to utilize substrates (fuels) during both rest and during exercise. The body normally changes sugars and starches to a usable form called glucose. Glucose is carried via blood stream to various tissues, such as skeletal muscle, to produce energy for cells. For glucose to enter the skeletal muscle a hormone called insulin must be present. Insulin is created by beta cells in the pancreas. In type 2 diabetes the sensitivity of skeletal muscle to insulin is compromised and the glucose can not enter the cell resulting in abnormal levels of glucose in the blood. These abnormal levels of glucose can be detrimental to ones health over extended periods of time.
Type 2 diabetes has been strongly linked to lifestyle factors such as diet and exercise. To combat this disease one is prescribed a healthy diet, regular physical activity, and medications. A current study called the Diabetes Prevention Program (DPP) compared diet and exercise to treatment with Glucophage in 3,234 people with impaired glucose tolerance (IGT), a condition that often precedes diabetes. The trial ended a year early because the data had clearly answered the main research questions. The DPP, conducted at 27 centers nationwide, is sponsored by the NIH. It is the first major trial to show that diet and exercise can effectively delay diabetes in a diverse American population of overweight people with IGT, a condition in which blood glucose levels are higher than normal but the individual is not yet considered to have diabetes (2). This study suggests that prevention might be the best way to fight the disease.
How do you know if you have diabetes?
There are two different tests your doctor can use to determine whether you have pre-diabetes: the fasting plasma glucose test (FPG) or the oral glucose tolerance test (OGTT). The blood glucose levels measured after these tests determine whether you have a normal metabolism, or whether you have pre-diabetes or diabetes. If your blood glucose level is abnormal following the FPG, you have impaired fasting glucose (IFG);
if your blood glucose level is abnormal following the OGTT, you have impaired glucose tolerance (IGT). 
Acute exercise
For those who already have it physical activity is one of the principal therapies to acutely lower blood glucose in type 2 diabetes due to its synergistic action with insulin in insulin-sensitive tissues. Acute bouts of physical activity can favorably change abnormal blood glucose and insulin resistance (4).
Chronic exercise
Regular physical activity promotes beneficial physiological changes in those with type 2 diabetes including lower resting and submaximal heart rate; increased stroke volume and cardiac output; enhanced oxygen extraction; and lower resting and exercise blood pressure. Those with type 2 diabetes are at increased risk for several cardiovascular risk factors, including high blood pressure and high cholesterol. Thus, therapy to control glucose levels and reduce long-term complications should focus on behavioral interventions that include a physically active lifestyle.
Recommended Physical Activity Program
Physical activity programs for those with type 2 diabetes without significant complications or limitations should include appropriate endurance and resistance exercise for developing and maintaining cardiorespiratory fitness, body composition, and muscular strength and endurance.
Risks and Complications of Exercise
When beginning an exercise program one should now the risks and complications that could take place. One could be come hypoglycemic, which is rare but does happen, usually to individuals that are on medications for diabetes. Self blood glucose monitoring is recommended for those with type 2 diabetes who engage in physical activity, especially during the initial activity sessions. Moreover, glucose monitoring is appropriate before and after an exercise bout. Given the knowledge and understanding of glucose levels, persons with type 2 diabetes, in consultation with their health care professional, can take appropriate action by reducing medications before exercise or increasing carbohydrate consumption before or after exercise to reduce the likelihood of hypoglycemia (1). Current guidelines for exercise with type 2 diabetes are as follow:
Do NOT exercise if one’s blood glucose is above 300 mg/dL prior to exercise. If one’s blood glucose is 70 mg/dL or below prior to exercise, have 2 to 5 glucose tablets, ½ cup (4 ounces) of fruit juice, or ½ cup of regular soft drink to raise one’s blood glucose. After 15 minutes, check blood glucose again. If it is still below 70 mg/dL, have another serving and repeat until one’s blood glucose is at least 70 mg/dL.
References
1. Albright, A. et. al. Exercise and type 2 diabetes. Med. Sci. Sports Exer. 32(7): pp. 1345-1360, 2000.
2. DIABETES PREVENTION PROGRAM RESEARCH GROUP. The Diabetes Prevention Program: design and methods for a clinical trial in the prevention of type 2 diabetes. Diabetes Care 22:623– 634, 1999.
3. HARRIS, M. I. Classification, diagnostic criteria, and screening for diabetes. In Diabetes in America, sponsored by the National Diabetes Data Group. NIH, NIDDK, Publication No. 95–1468, pp.15–36, 1995.
4. LAWS, A., and G. M. REAVEN. Physical activity, glucose tolerance, and diabetes in older adults. Ann. Behav. Med. 13:125–131, 1991.
