Exercise is frequently recommended to patients with type 2 diabetes as a means of controlling abnormal blood glucose levels and high blood pressure. Both are risk factors for cardiovascular disease, the leading cause of death among people with diabetes. A recent article in JAMA reviews mechanisms by which exercise can help preserve cardiovascular health in people with these two diseases.

A review of the literature

A MEDLINE search was used to find peer-reviewed articles on exercise training, type 2 diabetes, and hypertension published between January 1985 and June 2002. The author examined 235 sources, including large randomized trials, meta-analyses, smaller trials, non-randomized trials, and animal studies.

Summary of the research

A review of the data suggests that exercise can improve heart health in people with diabetes and hypertension by several mechanisms other than blood glucose and blood pressure control. While more randomized trials are needed to confirm this, the following is a summary of the research thus far.

• Exercise appears to improve left ventricular diastolic dysfunction (LVDD), which may be an early marker for diabetic cardiomyopathy.
• Exercise may improve endothelial function, which includes regulation of vasomotor tone, mediation of fibrinolysis and thrombosis, inflammatory response, and vascular smooth muscle growth.
• Exercise reduces total body and abdominal fat, which are mediators of blood pressure and glycemic control and possibly endothelial function. In addition, several studies have identified abdominal obesity as a risk factor for cardiovascular disease independent of total body fat.

Exercise prescription

Nearly all health professionals are in agreement that exercise should be part of diabetes and hypertension management. According to the American College of Sports Medicine and the American Diabetes Association, a general exercise plan should include the following:

• A warm-up and cool down (stretching, calisthenics, slow pace walking or cycling) period for 5 to 10 minutes.
• Aerobic exercise (walking, cycling, swimming, rowing) for 30 to 45 minutes, 3 or 4 times a week, and more often if weight loss is a goal.
• Resistance (weight) training at least twice a week. This should include 8 to 10 exercises to cover the major muscles in the upper and lower body.

Check the Disease Digest "Exercise" of this site for detailed guidelines on target heart rate ranges, and intensity, number of repetitions, and appropriate workloads for weight training (see first link below).