By Stephen Beech
Spending too long in a sauna without drinking enough water can trigger potentially deadly heat stroke, doctors have warned.
They spoke out after a woman in her early 70s was found unconscious in the sauna at her local gym in the West Midlands where she had been doing stretching exercises for around 45 minutes.
The woman was rushed to the hospital where she suffered a seizure, according to a report in the journal BMJ Case Reports.
Her core body temperature was 42 degrees Celsius (107.6F), compared to a normal temperature of 36.4C (97.5F).
She appeared to have suffered a minor heart attack and was kept in hospital for 12 days before being eventually allowed home.
Dr. William McIver, of the emergency department at Birmingham Heartlands Hospital, said: “Her blood pressure was extremely low, and her heart rate was extremely high.
“She had a seizure after her arrival in emergency care.
“She had previously been diagnosed with type 1 diabetes and an underactive thyroid, but she wasn’t a smoker or heavy drinker and was a regular gym goer, so had few risk factors.”
The woman was rapidly cooled with wet towels and a fan and given intravenous fluids and blood products to stabilize her.
Blood tests revealed malfunctioning kidneys and liver, evidence of a minor heart attack, and muscle tissue breakdown (rhabdomyolysis).
The woman, who has asked to remain anonymous, regained consciousness within two hours of reaching normal core temperature, but was confused and drowsy for two days.
Dr. McIver said: “By day three this had resolved and she had no further seizures during her inpatient stay, which lasted 12 days.
“After 26 days she had more or less fully recovered, except for some mild fatigue and mild liver function disturbance.”
He explained that it was just one case report after prolonged sauna use and, as far as doctors are aware, only nine other similar cases have been reported. But three of those patients died as a result.
Dr. McIver said: “Although relatively rare, heat stroke can be life-threatening, even in the absence of various underlying risk factors, such as heart, lung, or neurological disease, and heavy drinking or taking a cocktail of prescription meds.
“Heat stroke is defined as a sharp increase in core body temperature above 40C that is associated with acutely impaired brain function, and ‘non-exertional’ heat stroke results from prolonged exposure to high environmental temperatures.”
He added: “The prognosis of heat stroke varies according to patient factors, particularly extremes of age.
“Classical heat stroke in elderly people carries a mortality rate of more than 50%, and this increases further with each additional organ dysfunction.
“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.”
The woman told the journal: “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.
“As a regular sauna user, I never suffered any issues and, on reflection, I believe I had not drunk enough water.”
