Objective: We previously demonstrated a positive association between chronic aerobic exercise and dorsal foot skin blood flow during local heating in type 2 diabetic individuals. Thus, we hypothesized that a prior acute bout of maximal exercise would also have positive effects on postexercise blood flow.
Research design and methods: Subjects consisted of 32 individuals with type 2 diabetes and 26 nondiabetic control subjects further subdivided based on their physical activity status: diabetic exerciser (DE), diabetic sedentary (DS), control exerciser (CE), or control sedentary. Dorsal foot cutaneous blood flow was measured noninvasively by continuous laser-Doppler assessment at baseline and during local heating to 44 degrees C before and after a maximal bout of cycle exercise. Interstitial nitric oxide (NO) levels were measured concurrently in the foot dorsum.
Results: Increases in blood flow and its responsiveness to local heating to 44 degrees C were significantly lower in both diabetic groups compared with CE before maximal exercise, but perfusion responsiveness remained lower in DS subjects only after exercise (P < 0.05). Baseline skin blood flow was not different among groups preexercise, but it was significantly increased postexercise in DE subjects only. Interstitial NO levels were not significantly different at either time. At baseline, groups differed only in HbA(1c), fasting serum glucose, HDL cholesterol, and insulin resistance (homeostasis model assessment method).
Conclusions: All diabetic individuals exhibit a blunted responsiveness of cutaneous blood flow with local heating to 44 degrees C before maximal exercise compared with active nondiabetic individuals, but after an exercise bout, it remains significantly blunted only in diabetic individuals who are sedentary. These findings occur independently of changes in interstitial NO levels.