Home-Based Heat Therapy and Vascular Function of Adults Living with Type 2 Diabetes: Preliminary Analyses of a Randomized Controlled Trial
Authors: Debray Amelie , Barry Hadiatou , Dahhak Amine , Romero Steven , Iglesies-Grau Josep , Blondin Denis , Gagnon Daniel 
Published: May 2024

Background: Several studies indicate that various heat exposure interventions improve peripheral endothelial function and microvascular reactivity, as well as reduce central arterial stiffness and blood pressure in various populations. Nonetheless, few studies have considered the potential therapeutic effects of heat exposure for people living with type 2 diabetes mellitus (T2DM), who are at high cardiovascular risk. In addition, all heat therapy interventions investigated to date have been laboratory-based, which may limit long-term adherence. HYPOTHESES: This study aims is to determine the effects of a 12-week home-based heat therapy intervention on markers of vascular function in adults living with T2DM. The primary hypothesis is that heat therapy improves peripheral endothelial function relative to a sham intervention. Secondary hypotheses include improved microvascular reactivity, central arterial stiffness, and 24h blood pressure. METHODS: Thirteen adults (66 ± 10 years, 28.9 ± 6.0 kg/m2, 9 men/ 4 women) living with TD2M were randomized to 12 weeks of home-based heat therapy (n=7, lower leg immersion in 42°C water) or a thermoneutral sham intervention (n=6, lower leg immersion in 36°C water). Peripheral endothelial function (brachial artery flow-mediated dilation, FMD), microvascular reactivity (post-occlusive reactive hyperemia), arterial stiffness (carotid-femoral pulse wave velocity), and 24h blood pressure (ambulatory blood pressure monitoring), were measured before and after the intervention. RESULTS: Brachial artery FMD changed by 1.72% [95%CI, 0.06; 3.37] in response to heat therapy compared to 0.41% [-1.38; +2.20] in response to the sham intervention. Peak and total reactive hyperemia changed by 0.79 mL/min/mmHg [-0.27; 1.86] and by 1.77 mL/mmHg [0.73; 2.81], respectively, in response to heat therapy compared with 0.76 mL/min/mmHg [-0.38; 1.91] and 1.68 mL/mmHg [0.56; 2.80] in response to the sham intervention. Arterial stiffness changed by 0.55 m/s [-1.62; 2.71] in response to heat therapy compared with -1.60 m/s [-3.75; 0.57] in response to the sham intervention. The 24h-systolic and diastolic blood pressure changed by 6 mmHg [-1; +12] and 2 mmHg [-3; +7], respectively, in response to heat therapy compared with -2 mmHg [-10; +6] and -3 mmHg [-9; +3] in response to the sham intervention. CONCLUSION: These preliminary results suggest that 12 weeks of home-based lower leg hot water immersion improves brachial artery FMD in adults with T2DM. In contrast, the heat therapy intervention does not appear to improve microvascular reactivity, central arterial stiffness, or 24h blood pressure. Cardiometabolic Health Diabetes and Obesity Research Network and Diabète Quebec. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.