Get Healthy!

• Posted January 9, 2025

Sauna Misuse May Lead to Heat Stroke, Data Suggests

Basking in a sauna can be a nice way to relieve stress or relax muscles following a workout.

But soaking too long can increase a person’s risk of heat stroke, particularly if they aren’t well-hydrated, doctors warn.

Most cases of heat stroke occur on hot days, due to overexertion, researchers say.

However, “sauna use is a rare but potentially important cause of classical heat stroke,” Dr. William Jack McIver with Birmingham Heartlands Hospital in the UK wrote in a study published Jan. 7 in the journal BMJ Case Reports.

The new paper cited 10 cases of heat stroke caused by too much time in a sauna, including three that resulted in death.

The most recent case involved a woman in her early 70s who’d been found unconscious in her local gym’s sauna, where she had been doing stretching exercises for about 45 minutes.

Her core body temperature registered more than 107 degrees Fahrenheit by the time paramedics arrived. Her blood pressure was extremely low, and her heart rate was extremely high.

The woman suffered a seizure after her arrival at the ER. Blood tests revealed kidney and liver damage, evidence of a minor heart attack, and breakdown of her muscle tissue, researchers explained.

Doctors treated the woman by cooling her with wet towels and a fan. She also was given IV fluids and a blood transfusion to stabilize her.

The woman regained consciousness within two hours of reaching normal body temperature, but was confused and drowsy for two days. She wound up staying 12 days in the hospital.

“My experience has emphasized the dangers of saunas and how important it is to be fully hydrated on entering a sauna and for them to be regularly checked by staff,” said the woman, as quoted in the study. “As a regular sauna user I never suffered any issues and, on reflection, I believe I had not drunk enough water.”

“I am pleased to say I'm feeling well and appear to have made a full recovery,” she added.

The woman was lucky, McIver says.

“Classical heat stroke in elderly people carries a mortality rate of more than 50%, and this increases further with each additional organ dysfunction,” McIver wrote in his report.

Getting a person’s temperature back to normal is vital to ensuring their survival, he further explained.

“Once heat stroke has occurred, the key determinate of outcome is how rapidly a patient is cooled, as the time spent with elevated core body temperature is correlated to the degree of cellular damage,” McIver concluded.

More information

Harvard Medical School has more on heat strokes.

SOURCE: BMJ Group, news release, Jan. 7, 2024