Background Heat therapy has been suggested to improve cardiovascular function. However, the effects of hot sauna exposure on arterial compliance and the dynamics of blood flow and pressure have not been well documented. Thus, we investigated the short-term effects of sauna bathing on arterial stiffness and haemodynamics. Design The design was an experimental non-randomised study. Methods There were 102 asymptomatic participants (mean age, 51.9 years) who had at least one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73℃; humidity: 10-20%). Pulse wave velocity, augmentation index, heart rate, blood pressure, mean arterial pressure, pulse pressure, augmented pressure and left ventricular ejection time were assessed before, immediately after, and 30 min after a single sauna session. Results Sauna bathing led to reductions in pulse wave velocity, blood pressure, mean arterial pressure and left ventricular ejection time. Mean pulse wave velocity value before sauna was 9.8 m/s and decreased to 8.6 m/s immediately after sauna bathing ( p < 0.001 for difference), and was 9.0 m/s after the 30-minute recovery period ( p < 0.001 for analysis of variance). Systolic blood pressure was 137 mm Hg before sauna bathing, decreasing to 130 mm Hg after sauna ( p < 0.001), which remained sustained during the 30-minute recovery phase ( p < 0.001 for analysis of variance). After a single sauna session, diastolic blood pressure decreased from 82 to 75 mm Hg, mean arterial pressure from 99.4 to 93.6 mm Hg and left ventricular ejection time from 307 to 278 m/s ( p < 0.001 for all differences). Pulse pressure was 42.7 mm Hg before the sauna, 44.9 mm Hg immediately after the sauna, and reduced to 39.3 mm Hg after 30-minutes recovery ( p < 0.001 for analysis of variance). Heart rate increased from 65 to 81 beats/min post-sauna ( p < 0.001); there were no significant changes for augmented pressure and pulse pressure amplification. Conclusion This study shows that pulse wave velocity, systolic blood pressure, diastolic blood pressure, mean arterial pressure, left ventricular ejection time and diastolic time decreased immediately after a 30-minute sauna session. Decreases in systolic blood pressure and left ventricular ejection time were sustained during the 30-minute recovery phase.

Emerging evidence suggests beneficial effects of sauna bathing on the cardiovascular system. However, the effects of sauna bathing on parameters of cardiovascular function and blood-based biomarkers are uncertain. We aimed to investigate whether sauna bathing induces changes in arterial stiffness, blood pressure (BP), and several blood-based biomarkers. We conducted an experimental study including 102 participants (mean age (SD): 51.9 (9.2) years, 56% male) who had at least one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73 °C; humidity: 10-20%). Cardiovascular as well as blood-based parameters were collected before, immediately after, and after 30-min recovery. Mean carotid-femoral pulse wave velocity was 9.8 (2.4) m/s before sauna and decreased to 8.6 (1.6) m/s immediately after sauna (p < 0.0001). Mean systolic BP decreased after sauna exposure from 137 (16) to 130 (14) mmHg (p < 0.0001) and diastolic BP from 82 (10) to 75 (9) mmHg (p < 0.0001). Systolic BP after 30 min recovery remained lower compared to pre-sauna levels. There were significant changes in hematological variables during sauna bathing. Plasma creatinine levels increased slightly from sauna until recovery period, whereas sodium and potassium levels remained constant. This study demonstrates that sauna bathing for 30 min has beneficial effects on arterial stiffness, BP, and some blood-based biomarkers. These findings may provide new insights underlying the emerging associations between sauna bathing and reduced risk of cardiovascular outcomes.

We investigated the associations of cardiorespiratory fitness (CRF), physical activity (PA) with regard to aerobic and resistance training, and body mass index (BMI) with pulse wave velocity (PWV) and augmentation index (AIx) in middle‐aged adults with at least one cardiovascular risk factor. A total of 84 (46 men and 38 women) participated in the study. Cardiorespiratory fitness was measured using a maximal graded exercise test on a cycle ergometer and was defined as maximal power output (Wmax) normalized for body weight‐0.35. Participation in aerobic and resistance training was assessed by a detailed questionnaire and BMI was calculated as weight (kg)/[height (m2)]. Pulse wave velocity and AIx were measured using an applanation tonometry before (pre), immediately after (post), and after 10 min (post10) of maximal exercise test. Cardiorespiratory fitness, PA, or BMI was not associated with PWV or AIx. Pulse wave velocity decreased significantly from pre to post10 among those in the highest third of CRF (mean difference=−0.793 m/s, 95% CI = −1.494 to −0.091, p = .023) and in normal weight participants (p = .084 for time*group interaction mean difference=−0.781 m/s, 95% CI = −1.496 to −0.066, p = .029), but not among those in the other thirds of CRF or overweight or obese participants. Participants who had regular resistance training had continuously higher AIx from pre to post10 than those who had no regular resistance training (mean difference = −1.98, 95% CI = −4.02 to 0.069, p = .058). In conclusion, exercise may decrease PWV and AIx. Our results suggest that positive arterial responses to exercise could be slightly improved in fit and normal weight individuals.

Regular exercise and sauna bathing have each been shown to improve cardiovascular function in clinical populations. However, experimental data on the cardiovascular adaptations to regular exercise in conjunction with sauna bathing in the general population is lacking. Therefore, we compared the effects of exercise and sauna bathing, to regular exercise using a multi-arm randomized controlled trial. Participants (n = 47) aged 49 ± 9 years with low physical activity levels, and at least one traditional CVD risk factor were randomly assigned (1:1:1) to guideline-based regular exercise and 15-minute post-exercise sauna (EXS), guideline-based regular exercise (EXE), or control (CON), for eight weeks. The primary outcomes were blood pressure (BP) and cardiorespiratory fitness (CRF). Secondary outcomes included fat mass, total cholesterol levels, and arterial stiffness. EXE had a greater change in CRF (+6.2 ml/kg/min; 95% CI, +4.2. to +8.3 ml/kg/min) and fat mass, but no differences in BP when compared to CON. EXS displayed greater change in CRF (+2.7 ml/kg/min; 95% CI, +0.2. to +5.3 ml/kg/min), lower systolic BP (-8.0 mmHg; 95% CI, -14.6 to -1.4 mmHg) and lower total cholesterol levels compared to EXE. Regular exercise improved CRF and body composition in sedentary adults with CVD risk factors. However, when combined with exercise, sauna bathing demonstrated a substantially supplementary effect on CRF, systolic BP, and total cholesterol levels. Sauna bathing is a valuable lifestyle tool that complements exercise for improving CRF, and decreasing systolic BP. Future research should focus on the duration, and frequency of exposure to ascertain the dose-response relationship.

ObjectiveLoss of sex hormones has been suggested to underlie menopause-associated increment in cardiovascular risk. We investigated associations of sex hormones with arterial stiffness in 19–58-years-old women. We also studied associations of specific hormonal stages, including natural menstrual cycle, cycle with combined oral contraceptives (COC) and menopausal status with or without hormone therapy (HT), with arterial stiffness.MethodsThis study includes repeated measurements of 65 healthy women representing reproductive (n=16 natural, n=10 COC-users) and menopause (n=5 perimenopausal, n=26 postmenopausal, n=8 HT-users) stages. Arterial stiffness outcomes were aortic pulse wave velocity (PWVao) and augmentation index (AIx%) assessed using Arteriograph-device. Generalized estimating equation models were constructed to investigate associations of each hormone (wide age-range models) or hormonal stage (age-group focused models) with arterial stiffness. PWVao models with cross-sectional approach, were adjusted for age, relative fitness, fat mass and mean arterial pressure, while models with longitudinal approach were adjusted for mean arterial pressure. AIx% models used the same approach for adjustments and were also adjusted for heart rate.ResultsNegative and positive associations with arterial stiffness variables were observed for estradiol and follicle-stimulating hormone, respectively, until adjustment for confounding effect of age. In naturally menstruating women, AIx% was higher at ovulation (B=3.63, p&lt;0.001) compared to the early follicular phase. In COC-users, PWVao was lower during active (B=-0.33 - -0.57, p&lt;0.05) than inactive pills. In menopausal women, HT-users had higher PWVao (B=1.43, p=0.03) than postmenopausal non-HT-users.ConclusionsWhen using wide age-range assessments covering reproductive to menopausal lifespan it is difficult to differentiate age- and hormone-mediated associations, because age-mediated influence on arterial stiffness seemed to overrule potential hormone-mediated influences. However, hormonal status associated differentially with arterial stiffness in age-group focused analyses. Thus, the role of sex hormones cannot be excluded. Further research is warranted to resolve potential hormone-mediated mechanisms affecting arterial elasticity.