Many people turn to hydrotherapy, such as hot tubs, to ease lingering discomfort during recovery from illness. The warmth and buoyancy of the water can feel restorative after battling a systemic infection like COVID-19. However, the period following viral illness requires a cautious approach to any activity that places additional strain on the body. Understanding the specific physiological effects of a hot tub soak on a system still recovering from inflammation is necessary to evaluate its safety.
Understanding the Cardiovascular Risk
Hot tub use during post-COVID recovery poses a significant concern for the circulatory system, which can be vulnerable after a viral infection. The heat of the water causes blood vessels in the skin to dilate (vasodilation) as the body attempts to shed heat and regulate its core temperature. This widespread dilation results in a drop in overall blood pressure.
To counteract the fall in pressure, the heart must increase its output by significantly raising the heart rate. This demand places an immediate, measurable increase in cardiac load—the work required to maintain circulation. While this is a normal response for a healthy person, the risk profile is different for someone recovering from COVID-19.
Viral infections, including COVID-19, have been associated with an increased incidence of inflammatory conditions of the heart muscle (myocarditis) or the surrounding sac (pericarditis). This heightened risk is present even in individuals who had mild cases and were never hospitalized. When the heart muscle is inflamed, it is less efficient and more susceptible to stress.
Adding the heat-induced strain of a hot tub session onto an already compromised heart can exacerbate underlying cardiac damage. Studies show the risk of developing new cardiac issues, such as myocarditis, remains elevated for up to a year following the initial infection. Therefore, any activity that forces the heart to work harder must be approached with prudence during the recovery phase.
Managing Respiratory and Constitutional Symptoms
Beyond the heart, hot tub use interacts with systemic and respiratory symptoms that often persist after the acute phase of COVID-19. Deep heat exposure is problematic for individuals still experiencing low-grade fever or significant fatigue. Immersing in hot water can push the body’s temperature regulation too far, leading to rapid overheating and potentially worsening fatigue.
The heat promotes increased perspiration, which, combined with the humidity, leads to rapid fluid loss and dehydration. Since maintaining hydration is recommended for viral recovery, the dehydrating effect of a hot tub session can undermine this effort. Dehydration can contribute to feelings of dizziness and lightheadedness upon exiting the water.
The steam rising from the hot water can provide temporary relief for respiratory symptoms like congestion and cough, acting as a natural humidifier for irritated airways. The warmth can also help reduce muscle aches and joint stiffness, which are common complaints during post-COVID recovery. However, the overall systemic stress from the heat must be weighed against these localized benefits, especially for those with persistent shortness of breath or lung irritation.
Practical Guidelines for Safe Post-COVID Hydrotherapy
Before considering a hot tub soak, confirm that all acute symptoms, especially fever, have resolved. If lingering symptoms like chest pain, sustained shortness of breath, or unexplained heart palpitations are present, consultation with a healthcare provider is necessary. The safest approach is to ensure the body has fully transitioned out of the recovery phase.
If a soak is approved, limiting both the temperature and the duration is necessary. The water temperature should be set below the standard maximum, ideally below 100°F (38°C), to reduce cardiac strain and overheating risk. Session duration should be kept brief, with experts recommending no more than 10 to 15 minutes, particularly when starting out.
Remain attentive to your body’s signals during the soak, exiting immediately if you feel dizzy, nauseous, or experience a rapid increase in heart rate. Drinking water before and after the session is essential to counteract fluid loss caused by the heat. Starting with a very short session and gradually increasing the time, while staying within recommended limits, allows the body to adjust to the thermal stress.