Acute Lower Leg Heating Increases Exercise Capacity in Patients With Peripheral Artery Disease

In this pilot study, we tested the hypothesis that acute lower leg heating (LLH) increases postheating popliteal artery blood flow and 6-minute walk distance in patients with peripheral artery disease (PAD).

Six patients (5 male, 1 female) with PAD (69 ± 6.9 years; claudication: ankle-brachial index < 0.90) participated in 3 randomized treatment sessions (2-7 days apart): control or bilateral LLH conducted via water bath immersion (42°C; ~40-cm depth) for either 15 or 45 minutes. Popliteal artery blood flow (Doppler ultrasound) and arterial pressure were measured before and after LLH. Six-minute walk distance was measured on the control day and each experimental day 35 minutes post-LLH.

Popliteal artery blood flow increased after heating in a duration-dependent manner (P < .05, postheating vs control for both heating conditions and between them). Six-minute walk distance increased by 10% and 12% after 15- and 45-minute heating treatments, respectively (P < .05 vs control session).

Lower leg heating, for as short as 15 minutes, increases postheating leg perfusion and exercise capacity in patients with PAD.