The influence of exercise on foot perfusion in diabetes

Diabetic foot disease is associated with both macro- and microvascular disease. Exercise has both positive and negative effects on the perfusion of lower limbs with peripheral arterial occlusive disease (PAOD). We aimed to measure changes in foot perfusion following a brief period of lower-limb exercise in individuals with and without Type 2 diabetes and non-critical PAOD.

Subjects were allocated to groups according to the presence or absence of diabetes, PAOD on colour duplex imaging and clinically detectable peripheral neuropaIthy. Transcutaneous oxygen tension (TcPO(2)), transcutaneous carbon dioxide tension (TcPCO(2)), ankle-brachial pressure indices, toe pressures and toe-brachial pressure indices (TBI) were measured.

One hundred and sixteen limbs were studied in 61 subjects. Post-exercise, toe pressure and TBI increased in the non-diabetic group with arterial disease, but not in the groups with diabetes. Foot TcPO(2) values increased in groups with diabetes and TcPCO(2) decreased in all groups with arterial disease. Increased chest TcPO(2) and decreased TcPCO(2) were demonstrated in the groups with diabetes.

Elevations in foot TcPO(2) and reductions in TcPCO(2) indicate improved cutaneous perfusion response to local heating post-exercise. Elevated toe pressures in the non-diabetes group suggest that improved perfusion may be associated with enhanced lower limb macrovascular haemodynamics. However, improvements in TcPO(2) and TcPCO(2) at foot and chest sites in diabetes imply a global change in cutaneous perfusion. The results suggest that brief exercise results in an improvement in cutaneous perfusion in non-critical PAOD, particularly in individuals with diabetes.