Acute Improvement of Vascular Function with Finnish Sauna Bathing in Older Adults with Stable Coronary Artery Disease

Abstract

BackgroundFrequent Finnish sauna bathing is associated with a decreased risk of cardiovascular mortality in middle‐aged men, including men with pre‐existing cardiovascular diseases. However, the potential physiological adaptations that mediate the protective effect of Finnish sauna bathing remain to be determined. In healthy young and older adults, hot water immersion acutely improves macro‐ and microvascular functions, two independent predictors of cardiovascular events. Therefore, improved vascular function may represent one adaptation by which Finnish sauna bathing confers cardiovascular health benefits. However, the acute effect of sauna bathing on vascular function has yet to be investigated in individuals with established vascular dysfunction.ObjectiveTo test the hypothesis that a traditional Finnish sauna session acutely improves macro‐ and microvascular functions in older adults with stable coronary artery disease.MethodsEleven older adults (68 ± 9 years, 10 men / 1 woman) with a diagnosis of stable coronary artery disease were exposed to 2 bouts of 10 minutes in a dry Finnish sauna (80°C, 20% relative humidity), separated by 10 minutes of seated rest outside the sauna. Before and ~45 minutes after sauna bathing, vascular function was evaluated by flow‐mediated dilation (FMD) of the brachial artery. Maximal dilation during reactive hyperemia, expressed as a percentage of baseline diameter (%FMD), was used as an index of macrovascular function. Peak and area under the curve (AUC) forearm vascular conductance were used as indices of microvascular function. Mean skin temperature (Tsk), intestinal temperature (Tcore), oral temperature (Toral), heart rate (HR) and mean arterial pressure (MAP) were monitored throughout the protocol.ResultsDuring sauna bathing, Tsk (32.8 ± 0.4 to 42.4 ± 1.3°C, P<0.01), Tcore (36.2 ± 0.6 to 36.9 ± 0.7°C, P<0.01), Toral (36.5 ± 0.3 to 37.6 ± 0.3°C, P<0.01) and HR (58 ± 11 to 85 ± 15 bpm, P<0.01) increased, whereas MAP decreased (94 ± 6 to 82 ± 9 mmHg, P<0.01). At the time of FMD measurement, HR, MAP and Toral had returned to pre‐sauna values (all P>0.16), while Tsk (PRE: 32.8 ± 0.4°C, POST: 34.3 ± 0.5°C, P<0.01) and Tcore (PRE: 36.3 ± 0.7°C, POST: 36.7 ± 0.8°C, P<0.01) remained elevated at the time of post sauna FMD measurement. There was a trend towards an increased %FMD (2.9 ± 2.2 to 4.1 ± 2.4%, P=0.07) and peak vascular conductance (3.4 ± 0.9 to 4.0 ± 1.1 ml/min/mmHg, P=0.06) following sauna bathing, while no change was observed for vascular conductance AUC (1.6 ± 0.6 to 1.9 ± 0.8 ml/mmHg, P=0.23).ConclusionThese results suggest that macro‐ and microvascular functions are acutely improved following a typical Finnish sauna bathing session in older adults with stable coronary artery disease.Support or Funding InformationFunded by the Fonds de Recherche du Québec ‐ Santé (FRQS)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.