Background: Finnish sauna bathing habits are associated with a decreased risk of cardiovascular mortality. The physiologic adaptations mediating this association remain to be fully elucidated. This study tested the hypothesis that Finnish sauna bathing acutely improves peripheral flow-mediated dilation (FMD) in middle-aged and older adults with stable coronary artery disease (CAD).
Methods: Twenty-two adults (20 male, 2 female; 67 ± 10 years) with stable CAD underwent 2 periods of 10 minutes in a Finnish sauna (81.3 ± 2.7°C, 23 ± 3% humidity) separated by 10 minutes of thermoneutral rest. Before and 51 ± 8 minutes after sauna bathing, brachial artery FMD and postocclusive reactive hyperemia (PORH) were evaluated by means of Doppler ultrasound.
Results: Sauna bathing increased core temperature (mean +0.66°C [95% CI 0.54-0.77], P < 0.01) and heart rate (+27 beats/min [24-29], P < 0.01), and decreased systolic (-19 mm Hg [-31 to -6]; P < 0.01) and diastolic (-6 mm Hg [-11 to -1], P < 0.01) blood pressures. Brachial artery FMD was greater after sauna bathing (+1.21% [0.16-2.26], P = 0.04), whereas PORH was unchanged (peak: +0.51 mL/min/mm Hg [-0.13 to 1.15], P = 0.11; area under the curve: +0.21 mL/mm Hg [-0.12 to 0.54]; P = 0.19).
Conclusions: A typical Finnish sauna bathing session acutely improves peripheral FMD in middle-aged and older adults with stable CAD.
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