Using a hot tub when you have a fever is strongly discouraged and considered unsafe by medical professionals. A fever is an elevation of the body’s core temperature, typically above 100.4°F (38°C), indicating the body is fighting an infection. When ill, the body’s heat regulation system is already under stress and adjusting to a higher internal temperature set-point. Introducing a high external heat source like a hot tub can easily overwhelm this compromised system, potentially leading to dangerous health complications.
How External Heat Disrupts Thermoregulation
A fever is a controlled response where the brain raises the body’s internal temperature set-point. To manage this elevated temperature and shed excess heat, the body employs mechanisms like vasodilation and sweating. Submerging the body in a hot tub, typically set between 100°F and 104°F, counteracts these natural cooling efforts. The surrounding hot water prevents the effective evaporation of sweat, which is the body’s primary method of heat loss in a warm environment.
The conflict between the internal fever set-point and the external heat source can lead to an uncontrolled rise in core body temperature. This condition is called hyperthermia, which is distinct from fever because it represents a failure of the body’s ability to regulate its temperature. Hyperthermia occurs when the body absorbs more heat than it can dissipate, quickly pushing the core temperature to unsafe levels.
Acute Dangers of Submersion and High Temperatures
The failure of thermoregulation in a hot tub leads to several immediate health hazards. One primary concern is severe dehydration, which is accelerated because the hot water prevents sweat from cooling the body, causing profuse sweating without relief. The high heat also causes widespread peripheral vasodilation, which dramatically lowers blood pressure as blood rushes away from the core to the skin. This combination of low blood pressure and dehydration places significant strain on the cardiovascular system, forcing the heart to work harder to maintain circulation.
The resulting drop in blood pressure and core temperature instability substantially increases the risk of syncope, or fainting, and severe dizziness. Losing consciousness while submerged in water presents a clear and immediate danger of drowning. Overheating can quickly progress to heat exhaustion or heat stroke, necessitating immediate medical attention.
Safe Alternatives for Comfort and Relief
Rather than using a hot tub, several safe and effective methods can provide comfort and help manage a fever. Hydration is paramount, so drinking plenty of clear fluids, such as water or electrolyte-containing beverages, is recommended to replace fluids lost due to the fever. Over-the-counter fever reducers, like acetaminophen or ibuprofen, can also be used as directed to help temporarily lower the body’s temperature set-point and alleviate discomfort.
Applying a cool, damp compress to pulse points, such as the forehead and wrists, can offer localized relief from overheating. Taking a lukewarm or tepid bath or shower is a much safer alternative to a hot tub. The water should feel slightly cool, not cold, as cold water can trigger shivering, which paradoxically increases the body’s internal heat production.