In contrast to what is seen in nondiabetic, physically active subjects, a single bout of moderate exercise does not improve cutaneous perfusion in patients with type 2 diabetes or those with a sedentary lifestyle. The reason for this difference is unclear, but it does not seem to relate to nitric oxide (NO), a well-known vasodilator, since exercise-induced changes in NO levels are similar in each group of subjects.
The results stem from a study of skin perfusion in 17 diabetic sedentary subjects, 15 diabetic exercisers, 13 nondiabetic sedentary subjects, and 13 nondiabetic exercisers. Based on self-report, the exercisers had completed at least 30 minutes of aerobic exercise three times per week for 6 months or longer.
Each of the subjects completed a maximal exercise protocol on a cycle ergometer in order to calculate the moderate level of exercise that would be applied for 20 minutes on the test day. Skin perfusion in the dorsum of the foot was assessed before and after exercise using standard heat-responsive measures.
Lead author Dr. Sheri R. Colberg, from Old Dominion University in Norfolk, Virginia, and colleagues report their findings in the October issue of Diabetes Care.
At baseline, nondiabetic and diabetic exercisers displayed significantly greater skin perfusion than did diabetic sedentary subjects. As noted, the exercise intervention improved skin perfusion in the nondiabetic exercise group, but not in the other three groups.
Interstitial NO levels were similar in each group before and after exercise, the report indicates.
The findings suggest that the impact of exercise on skin perfusion "is negatively affected by both diabetes and inactivity, independent of NO production in the skin," the authors conclude.
Diabetes Care 2006;29:2316-2318.