Comparison of Acute Sauna With Exercise and Sauna
Condition: Cardiovascular Risk Factor; Blood Pressure; Arterial Stiffness
Study type: Interventional

Summary: 
      Sauna bathing has been associated with a lower risk for cardiovascular disease (CVD)
      outcomes, improved vascular endothelial and cardiac function, reduced oxidative stress and
      lower blood pressure. Earlier studies conducted by the investigators have showed positive
      alterations of arterial stiffness and hemodynamics through sauna bathing.

      Some studies have sought to utilize sauna bathing as an intervention after exercise with
      promising and synergistic results, although the effects on populations with cardiovascular
      risk factors are less clear. Furthermore, studies investigating the use of both exercise and
      sauna bathing in combination has been somewhat limited. However, results from some studies
      speculate that adjunctive exercise and sauna interventions may be useful for aging and
      clinical patient population groups.

      Given that heat therapy and sauna use is gaining more worldwide popularity, the investigators
      sought to compare the acute hemodynamic effects between sauna use alone and a short bout of
      exercise followed by sauna exposure. It was hypothesize that the combination of exercise and
      sauna will elicit greater changes than sauna alone. To achieve this, we standardized the
      protocol duration (30 minutes).
    

Detailed description: 
      In this crossover trial, all study participants underwent two interventions, each on a
      separate occasion (>72 hours apart). A standalone 30-minute sauna at 75°C (S), and 15-minutes
      of cycling on the stationary bike at 75% maximum heart rate, followed by 15-minutes of sauna
      exposure (ES). A cycling exercise test was conducted on a separate day prior to the
      experiment to ascertain individual maximal exercise heart rates, which was then used to
      calculate individual 75% maximum.

      After the ﬁrst 15-minute period of S, the participants left the sauna room to have a quick
      shower (<30 seconds) before going back for the second 15-minute period. The same sauna
      bathing room (75°C) was used for all participants and the cycling exercise was conducted
      within 10 meters of the sauna room to minimize transit time during ES. Participants were
      instructed to abstain from eating 2h, caffeine 12h and alcohol 24h prior to the measurements.
      Food intake was not standardized. Fluid was consumed ad libitum. A medical physician was in
      attendance at all times and participants were allowed to leave the sauna or stop the
      experiment at any time if they felt uncomfortable.

      Brachial blood pressures and pulse wave velocity (PWV) as a measure of arterial stiffness,
      were taken in their respective order at three different time points; before (PRE),
      immediately after (POST), and after a 30-minute recovery (POST30). Transit time from the
      cessation of the intervention to POST measurements were kept under 60 seconds. All
      measurements were performed by the same assessor to minimize ascertainment biases.

      Participants were permitted to take a quick shower (<30 seconds) before POST measurements
      were taken. Water temperature or the shower was not controlled and participants could freely
      select their desired temperature. Thereafter, they were instructed to rest in a designated
      waiting lounge (mean temperature 21°C) in a seated position for a duration of 30-minutes
      before the last measurement (POST30) was taken.
    

Intervention name(s): Aerobic exercise; Sauna bathing
Intervention type(s): Other; Other
Intervention description(s): 15 minutes of aerobic exercise using stationary bicycle; Passive heat exposure
Allocation: Non-Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Sauna bathing; Aerobic exercise; Thermal therapy; Passive heat