Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors

Abstract

OBJECTIVESWe sought to determine whether sauna therapy, a thermal vasodilation therapy, improves endothelial function in patients with coronary risk factors such as hypercholesterolemia, hypertension, diabetes mellitus and smoking.BACKGROUNDExposure to heat is widely used as a traditional therapy in many different cultures. We have recently found that repeated sauna therapy improves endothelial and cardiac function in patients with chronic heart failure.METHODSTwenty-five men with at least one coronary risk factor (risk group: 38 ± 7 years) and 10 healthy men without coronary risk factors (control group: 35 ± 8 years) were enrolled. Patients in the risk group were treated with a 60°C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once a day for two weeks. To assess endothelial function, brachial artery diameter was measured at rest, during reactive hyperemia (flow-mediated endothelium-dependent dilation [%FMD]), again at rest and after sublingual nitroglycerin administration (endothelium-independent vasodilation [%NTG]) using high-resolution ultrasound.RESULTSThe %FMD was significantly impaired in the risk group compared with the control group (4.0 ± 1.7% vs. 8.2 ± 2.7%, p < 0.0001), while %NTG was similar (18.7 ± 4.2% vs. 20.4 ± 5.1%). Two weeks of sauna therapy significantly improved %FMD in the risk group (4.0 ± 1.7% to 5.8 ± 1.3%, p < 0.001). In contrast, %NTG did not change after two weeks of sauna therapy (18.7 ± 4.2% to 18.1 ± 4.1%).CONCLUSIONSRepeated sauna treatment improves impaired vascular endothelial function in the setting of coronary risk factors, suggesting a therapeutic role for sauna treatment in patients with risk factors for atherosclerosis.