When people get sick, sweating is a common symptom. This physiological response is tied to the body’s natural defense mechanisms. Understanding sweating during sickness involves recognizing how the body maintains its internal temperature and uses fever to fight pathogens.
How Your Body Regulates Temperature
The human body maintains a stable internal temperature, typically around 98.6°F (37°C), through a process called thermoregulation. The hypothalamus acts as the body’s thermostat, receiving temperature signals. If the body’s temperature deviates from this set point, the hypothalamus initiates responses to either generate or release heat. If the body is too warm, it promotes heat loss through mechanisms like sweating and vasodilation, which widens blood vessels in the skin. If the body is too cold, the hypothalamus can trigger shivering to generate heat.
The Purpose of Fever
When an infection occurs, the body often responds with a fever. This elevated body temperature is a deliberate immune system action. Pyrogens, from pathogens or the body’s own immune cells, signal the hypothalamus to reset its thermostat to a higher temperature. This elevated temperature creates an environment less favorable for bacteria and viruses, hindering their growth. It also enhances the activity of certain immune cells, making defense more efficient.
Sweating’s Role in Illness
Sweating plays a specific role during illness, particularly as a fever begins to resolve. When the immune system has successfully combated the infection, or when fever-reducing medications are used, the hypothalamus resets the body’s temperature set point back to its normal range. At this point, the body’s actual temperature is still elevated above this new, lower set point. To cool down to the normal temperature, the body activates its cooling mechanisms, including vasodilation and increased sweat production. This is why a person often experiences significant sweating as their fever “breaks,” to release excess heat and return to a balanced state.
When Sweating Signals Something More
While sweating during illness is a natural part of recovery, certain situations warrant closer attention. Significant fluid loss, especially during a fever, can lead to dehydration. Symptoms of dehydration include:
- Increased thirst
- Dry mouth
- Reduced urination
- Lightheadedness
- Fatigue
Staying adequately hydrated with water or electrolyte-rich fluids is important to counteract this fluid loss.
Other factors can contribute to sweating beyond the fever cycle. Certain medications, including fever reducers, antidepressants, and steroids, can cause sweating as a side effect. Stress and anxiety from illness can also trigger increased sweating. While most sweating during illness is benign, excessive or persistent sweating with concerning symptoms like chest pain, confusion, or an unresolved fever, may indicate a serious issue requiring medical evaluation.