The belief that a person can “sweat out” a common cold in a sauna is a widely held folk remedy. The common cold is predominantly caused by the rhinovirus, which infects the upper respiratory tract. This practice suggests that intense, externally applied heat can speed up recovery by eliminating the illness. Examining the science behind fever response and viral replication reveals that using a sauna to cure a cold is not a valid approach.
The Science of High Heat and Viral Illness
The idea that a sauna can cure a cold stems from the body’s natural defense mechanism: the fever. A fever raises the core body temperature, an adaptive immune response meant to make the internal environment inhospitable for pathogens and enhance immune cell activity. The rhinovirus thrives best at temperatures slightly cooler than the core body temperature, typically around 33 to 35 degrees Celsius, which is the temperature found in the nasal passages.
The localized heat of a sauna does not effectively replicate the systemic, controlled temperature increase of a natural fever. While a sauna raises the skin and surrounding air temperature, the effect on the body’s internal core temperature is minimal and temporary. Even if the core temperature rises slightly, the heat is not sustained long enough or intensely enough to neutralize the virus throughout the body.
Sweating is a mechanism for cooling the body, consisting primarily of water and salts; it does not eliminate the virus itself. The virus has already replicated and established itself within the cells of the respiratory tract. Sweating cannot clear these infected cells from the system, making external heat induction of sweat scientifically unfounded for viral clearance.
Sauna Use for Respiratory Symptom Alleviation
While saunas cannot cure a cold, the environmental conditions they create can offer temporary relief for certain symptoms. The warm, humid air of a traditional sauna or steam room can help loosen thick mucus secretions in the nasal and chest passages. This temporary thinning of mucus can reduce congestion and make breathing feel easier for a short duration.
The heat from a sauna promotes increased blood circulation, which may help soothe muscle aches that often accompany a cold. The general relaxation induced by the warm environment can also reduce stress and provide a brief psychological reprieve from the discomfort of illness. This relief is purely symptomatic; the underlying viral infection remains unaffected, and the duration of the illness will not be altered.
Critical Health Risks of Sauna Use While Sick
Using a sauna while sick carries specific health risks, especially when the illness involves fever or gastrointestinal symptoms. The primary danger is severe dehydration, as the body is already using extra fluids to fight the infection and regulate internal temperature. Excessive sweating rapidly depletes the body’s fluid reserves, which can worsen cold symptoms like headaches, fatigue, and dizziness.
A person should avoid a sauna if they have a fever, as the elevated external temperature adds significant stress to an already compromised system. Combining a fever with the heat stress of a sauna can push the core body temperature too high, leading to dangerous overheating. The heat also increases heart rate to pump blood to the skin for cooling, placing an unnecessary burden on the cardiovascular system. This increased strain can lead to orthostatic hypotension, a sudden drop in blood pressure resulting in lightheadedness or fainting upon exiting the hot room.