Infrared sauna as exercise-mimetic? Physiological responses to infrared sauna vs exercise in healthy women: A randomized controlled crossover trial.
Level 2 - randomized trial
Randomized controlled crossover trial
PubMed 34954348 · doi:10.1016/j.ctim.2021.102798
What was done
Ten healthy women (mean age 36 ± 9 years) in Brisbane, Australia completed a randomized controlled crossover trial comparing three 45-minute conditions: resting control, infrared sauna, and moderate-intensity indoor bicycling. Primary outcomes were tympanic and skin temperatures, respiratory rate, blood pressure, arterial stiffness, and heart rate variability.
What was found
Tympanic temperature increased significantly more during infrared sauna than resting control (mean difference +1.05 °C ± SEM 0.12 °C, 95% CI: 0.73 to 1.36, p < 0.0005) and exercise (+0.79 °C ± SEM 0.12 °C, 95% CI: 0.49 to 1.08, p < 0.0005). Respiratory rates were significantly higher during exercise compared to resting control (mean diff +7.66 ± SEM 1.37, 95% CI: 4.09 to 11.23, p < 0.0005) and infrared sauna (mean diff +6.66 ± SEM 1.33, 95% CI: 3.20 to 10.11, p < 0.0005). No statistically significant differences were detected between any conditions for blood pressure, arterial stiffness, or heart rate variability.
Why it matters
These findings suggest that acute physiological responses to infrared saunas are primarily thermoregulatory and do not produce the immediate cardiorespiratory or cardiovascular activation seen with moderate exercise.
Limits
The study was very small (n = 10) and restricted to healthy adult women, limiting generalizability. It only measured acute 45-minute responses rather than long-term cardiovascular adaptations or effects in clinical populations.
Cited by
- context Deliberate heat exposure through a sauna or hot tub mimics the physiological cardiovascular response of moderate-intensity cardiovascular exercise.