Foot ulcers are a common complication of diabetes, due to macro- and microvascular changes that lead to neuropathy. But despite treatment with standard interventions such as debridement and pressure relief, many diabetic foot ulcers persist as nonhealing wounds, say researchers from Nnamdi Azidiwe University and University of Nigeria.
Oxygenation is key to keep the tissues healthy, the researchers say. We already know that exercise enhances blood circulation and improves vascular blood perfusion and capillary oxygen tension. However, little research has associated increased vascular blood perfusion with wound healing in diabetic foot ulcers, the researchers say. They reanalyzed results from 1 of their earlier studies to find out whether aerobic exercise would lead to healing.
In a 12-week program, 61 patients with type 1 or 2 diabetes mellitus were randomly assigned to an intervention or control group. Each patient had had a persistent ulcer of at least 1 cm2. The intervention group rode a bicycle ergometer at 60% of their maximum heart rate and progressed to 85%. The researchers tested them for oxygen percentage saturation and ankle brachial index (ABI) at baseline every 2 weeks.
At the end of the program, the researchers found a “sharp contrast” between the 2 groups, including a significant difference in the oxygen percentage saturation (99.00 vs 97.20) and the ABI. The reduction in wound size was also significant for the exercise group.
There is evidence, the researchers say, that exercise enhances blood circulation by lowering plasma glucose concentration. Normally, endothelial cells metabolize the circulating blood glucose—unless they are overwhelmed by glucose molecules during hyperglycemia. Previously, the researchers also noted that plasma glucose dropped significantly, mostly at the end of the fourth week of the exercise program.
In this study, increases in ABIs, the researchers say, imply enhanced oxygen supply to the extremities. During the fourth week, they found greater wound size reductions and the ABI significantly correlated with oxygen percentage saturation. The ankle brachial index may be a useful tool, the researchers suggest, for predicting improvement in oxygen percentage saturation.
The researchers’ findings lead them to recommend that nonweight bearing exercise be made a “cornerstone” of management for people with diabetic foot ulcers.
Nwankwo MJ, Okoye GC, Victor EA, Obinna EA. Int J Diabetes Res. 2014;3(3):41-48.