Consistent, moderate exercise plays an important role in the prevention and management of type 2 diabetes. Almost all people who eventually develop type 2 diabetes first have a condition known as prediabetes, in which glucose (blood sugar) is elevated but not yet high enough to be classified as diabetic.

Uncontrolled or high glucose (hyperglycemia) can trigger a variety of complications in people with type 2 diabetes, including:

• Heart conditions and stroke
• Kidney damage (diabetic nephropathy)
• Nerve damage (diabetic neuropathy)
• Blindness due to diabetic retinopathy, glaucoma or cataracts
• Amputation due to ulcer or other foot problems
• Diabetic coma
• Sexual dysfunction
• Dental problems

Prediabetes does not always progress to type 2 diabetes. Exercise, a nutritious diet and a normal body weight can delay and, in some cases, even prevent the onset of type 2 diabetes.

Exercise is a cornerstone of managing type 2 diabetes, along with:

• Meal planning and nutrition counseling
• Regular medical care
• Antidiabetic agents (if necessary)
• Insulin (if necessary)

A major factor in the development of type 2 diabetes is insulin resistance. The body produces an amount of insulin that should be adequate to meet its needs, but is unable to detect its presence or use it properly. When the body cannot efficiently use insulin, it cannot regulate glucose.

Some people are at higher risk for developing type 2 diabetes. Age, genetics, race and ethnicity, weight and other factors all play a role in the likelihood of developing resistance to insulin. Exercise can delay or prevent the onset of diabetes because it increases the body's sensitivity to insulin, which allows the body to use the hormone more effectively.

People who have type 2 diabetes who take certain oral antidiabetic medications, including sulfonylureas (drugs that increase insulin production of the pancreas) and meglitinides (drugs that lower the circulating levels of blood glucose), should pay particular attention to their glucose levels during exercise. These individuals are at increased risk for developing hypoglycemia (low blood sugar), which can be life-threatening. 

In addition to improving overall fitness, benefits of exercise for people with type 2 diabetes include:

• Controlling glucose, cholesterol and blood pressure
• Fighting childhood obesity and adult obesity
• Enhancing cardiovascular function
• Reducing the need for medications, as determined by a physician
• Preventing or delaying complications of diabetes

In addition, exercise helps prevent or control gestational diabetes, a form of diabetes that can develop in women during pregnancy. Exercise also plays a role in managing maturity-onset diabetes of the young, a genetic disorder that is sometimes considered a form of type 2 diabetes.

People are often advised to get 30 minutes of exercise at least five days a week. However, patients should consult their physician about what level of exertion and what amount and types of exercise are best for them.