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.

In a rare medical case, a woman in her 70s was hospitalized with heat stroke after stretching in a sauna for 45 minutes.

Prolonged sauna sessions may put bathers at risk of heat stroke, especially if they haven't consumed enough water beforehand, doctors have warned in the journal BMJ Case Reports. The warning comes after medical professionals treated a woman in her early 70s who required hospital admission following an extended sauna session at her local gym.

"Sauna use is a rare but potentially important cause of classical heat stroke," the doctors of a new case report warn.

Sauna users have been urged to stay hydrated after a woman suffered severe heat stroke with multi-organ failure after basking for too long in the heat. Experts from Birmingham Heartlands Hospital described how a patient needed hospital care for 12 days after heat stroke led to a number of serious health problems including a heart attack.

Prolonged use of saunas can pose serious health risks, including heat stroke, especially for individuals who are not adequately hydrated. Doctors are highlighting these dangers in the BMJ Case Reports after treating a woman who required hospitalization due to severe heat stroke following a long sauna session.

Discover the hidden risks of prolonged sauna use and the crucial importance of hydration to prevent heat stroke.

Heat stroke is defined as a sharp increase in core body temperature above 40C that is associated with acutely impaired brain function.