Which Is Better? Hot Tub Or Sauna?

The ancient Greeks took therapeutic hot baths at least as early as 1000 BC and, in Finland, sauna bathing is believed to date back as far as 7000 BC, according to National Geographic.

Alongside other University of Oregon researchers, human physiology doctoral student Jessica Atencio set out to find the answer by putting different heat therapies to the test in a head-to-head comparison.

Atencio tested acute, meaning immediate, short-term, responses to heat therapy in hot tubs, traditional saunas and far-infrared saunas.

"They're some of the most commonly utilized in both research and everyday life," Atencio said. "While research has studied the benefits of these different types of heating modalities, most studies only look at using one form."

Atencio was the lead author on the study published in June in the American Journal of Physiology.

Hot tubs might offer greater health benefits than saunas, Atencio's work revealed.

The main variable Atencio and her team were looking to measure was core body temperature. Atencio used core temperature pills — essentially ingestible thermometers — to track what happened to the subjects throughout the study. A temporarily raised core body temperature can help lower blood pressure, stimulate the immune system and, over time, improve the body’s response to heat stress.

The thermometers showed hot water immersion was the most impactful in increasing core body temperature, causing an increase in blood flow, which is good for vascular health.

Atencio's team also took blood samples from the subjects, revealing only hot-water immersion produced beneficial inflammation.

Atencio said she wasn't surprised by the evidence that hot tubs are most effective in increasing core temperature, because your body can't sweat as efficiently under water. However, the study did reveal something unexpected.

"We were surprised to see almost minimal to no change in the core temperature with the (far infrared) sauna, because, technically, the temperature is a lot hotter than the hot tub," Atencio said.

All the testing was done in the Bowerman Sports Science Center's hot tubs and saunas. The center isn't for recreation. The Bowerman Center, located in Hayward Field, features state-of-the-art facilities for all things sports science.