Background: Intermittent claudication, the hallmark symptom of peripheral artery disease (PAD), causes exertional leg pain that resolves with rest, and reduced muscle oxygenation during walking likely contributes to this pain. Although exercise therapy reduces symptoms and improves function, claudication during exercise often limits adherence. Heating therapy may enhance skeletal muscle perfusion and oxygenation, but its effects in PAD remain unclear. The aim of this study is to evaluate whether lower-limb heating improves muscle perfusion and oxygenation, measured by near-infrared spectroscopy (NIRS), during walking in patients with PAD. We hypothesized that bilateral lower-limb heating would attenuate the decline in muscle oxygenation during walking in patients with PAD. Methods: Seven PAD patients (71 ± 10 years; 7M) and nine healthy controls (49 ± 17 years; 5M/4F) participated the study. Participants performed a treadmill walking test using the Gardner protocol (2 mph, 2% grade increases every 2 minutes) during two randomized visits: (1) a non-heating control trial and (2) a trial with bilateral lower-limb heating before exercise. For the heating trial, lower legs and feet were immersed in 40–42°C water for 30 minutes. Muscle oxygenation was assessed by NIRS before and after heating and throughout treadmill exercise. Results: Treadmill exercise significantly reduced calf muscle oxygenation in both PAD patients and healthy subjects in both trials (all P < 0.001). Lower limb heating increased muscle oxygenation in PAD patients (P = 0.01) and healthy subjects (P = 0.001) at rest. In healthy controls, muscle oxygenation during the whole exercise paradigm did not differ between thermal conditions (two-way ANOVA, P = 0.590), and no interaction between exercise and thermal condition was observed (P = 0.335). In contrast, PAD patients showed a significant exercise-by-thermal-condition interaction (P = 0.005), with higher muscle oxygenation during the later exercise stages in the heating trial compared with the non-heating trial. Moreover, a significant group difference was observed in the exercise-induced change in muscle oxygenation with and without heating (P = 0.035). Discussion and Conclusion: These findings indicate that acute bilateral lower-limb heating attenuates the exercise-induced decrease in muscle oxygenation in patients with PAD, but not in healthy individuals. We speculate that local vasodilation and increases in blood flow induced by acute lower limb heating have a significant effect on the changes in muscle oxygenation during exercise. Our results suggest the potential benefits of bilateral lower limb-heating therapy as an adjunct treatment option for patients with PAD. Support and Funding NIH R01HL141198 and R01HL164571 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Atreya et al. (2026) studied this question.