Sauna bathing, involving exposure to heat or steam, is widely used for relaxation and health benefits. People often wonder if this heat therapy is safe or even helpful when they are feeling unwell. Understanding the body’s physiological reaction to intense heat is paramount before deciding whether to use a sauna while battling an illness.
The Body’s Response to Heat Stress
Entering a high-temperature environment triggers a powerful thermoregulatory response in the body. The heat rapidly elevates the skin temperature, which in turn causes the core body temperature to rise slightly. To prevent overheating, the body increases blood flow to the skin through vasodilation (the widening of blood vessels).
This process requires the heart to work harder, often raising the heart rate to 100 to 150 beats per minute, comparable to moderate physical exercise. Profuse sweating is the body’s primary cooling mechanism, and a short sauna session can lead to the loss of a pint or more of fluid. When the body is already compromised by infection, this added cardiovascular strain and fluid loss can become counterproductive and potentially dangerous.
When Sauna Use Is Contraindicated
The most significant contraindication for sauna use is the presence of a fever. A fever signals that the body’s internal temperature regulation system is already working overtime to fight an infection. Introducing external heat stress can push the body closer to a dangerous state of overheating or hyperthermia.
Sauna use should be avoided when experiencing systemic illnesses like the flu, a stomach virus, or conditions accompanied by body aches or extreme fatigue. These symptoms indicate a widespread immune response that is already taxing the body’s energy reserves and cardiovascular system. Adding the equivalent of a moderate workout in the form of heat stress can severely worsen symptoms and delay recovery.
Illness involving active fluid loss, such as vomiting or diarrhea, makes the risk of dehydration exceptionally high and prohibits sauna use. The body’s inability to maintain hydration, combined with the rapid fluid loss from sweating, increases the likelihood of lightheadedness, dizziness, and even fainting. If a respiratory illness is severe, or involves a deep, persistent cough, the high heat and humidity may also cause increased discomfort and should be avoided. Focus must be on rest, hydration, and medical consultation rather than thermal therapy.
Potential Relief for Mild Respiratory Symptoms
For individuals experiencing only mild, localized symptoms, such as a runny nose or sinus congestion without fever, a short exposure to heat may offer temporary relief. The warm air, particularly in a steam room or a wetter sauna, can act to loosen mucus in the nasal passages and airways. This humid environment may temporarily ease breathing by promoting drainage and relaxing the airways.
The benefit is purely symptomatic and does not treat the underlying viral infection. For some people with respiratory issues, the dry heat of a traditional sauna can irritate the airways, making congestion feel worse. If congestion is accompanied by any signs of a worsening condition, such as increasing body aches or the onset of a fever, the person must immediately cease sauna use and adhere to the strict avoidance guidelines.
Essential Safety Measures and Hydration
If a person with mild symptoms uses a sauna, strict safety measures must be enforced. The duration of the session should be significantly reduced, with a maximum limit of 5 to 10 minutes to minimize cardiovascular strain and fluid loss. It is also important to avoid public saunas when feeling sick to prevent the spread of illness to others.
Hydration is important, requiring water or electrolyte-rich drinks before and immediately after the short session. Individuals must pay close attention to their body’s signals and exit the sauna immediately if they feel dizzy, nauseous, or suddenly weak. Resting in a cool environment after leaving the sauna is necessary to allow the heart rate and body temperature to return to normal.