A new study done by researchers in the Bowerman Sports Science Center at the University of Oregon, compared the physiological effects of soaking in hot tubs to sitting in a traditional dry heat sauna or a more modern far-infrared sauna.
Hot tubs and saunas can both soothe aching muscles and provide welcome warmth, but hot tubs might offer greater health benefits.
By raising core body temperatures, soaking in hot water can help lower blood pressure, stimulate the immune system and, over time, improve the body’s response to heat stress. Moreover, those effects can last beyond the minutes spent directly in heat treatment.
“We compared the most commonly utilized modalities of passive heating as they’re used in everyday life and studied in scientific research. No studies have compared the acute responses between the three,” said study lead author Jessica Atencio, a doctoral student in the lab of Christopher Minson.
Under the guidance of Minson, the Kenneth M. and Kenda H. Singer Endowed Professor of Human Physiology and director of the Bowerman Center, researchers monitored body temperature, blood pressure, heart rate, cardiac output (the amount of blood the heart pumps per minute) and immune cell populations and blood biomarkers of inflammation. Data were collected before, during and after subjects soaked in a hot tub and sat in traditional dry heat and far-infrared saunas.
Image Credits: HUUM │sauna heaters@Pexels | Cropped by GBN
The study looked at 10 men and 10 women who exercised regularly and ranged in age from 20 to 28 years old. The goal was to isolate the physiological responses to each heating method in a young, healthy population.
“We saw that hot water immersion was the most impactful in increasing core body temperature, which is the main stimulus for these subsequent responses. Increasing body temperature causes an increase in blood flow, and just the force of blood moving across your vessels is beneficial for your vascular health,” Jessica Atencio remarked.
While the research team took blood samples from subjects after each kind of heat therapy, only hot-water immersion produced an inflammatory response as measured by the levels of inflammatory cytokines, a kind of immune signaling molecule, and immune cell populations.
Atencio stated that, “Hot water immersion gives you the most robust changes in core temperature because you can’t effectively dissipate heat as you can if you have contact with the air and you’re sweating to cool the body. When you’re submerged in water, the sweat mechanisms aren’t efficient.”
