Can heat stroke cause residual heat intolerance?

From the Guidelines

Yes, heat stroke can cause residual heat sensitivity, as it can damage the body's thermoregulatory system, particularly the hypothalamus, leading to impaired sweating responses and reduced ability to dissipate heat efficiently. After experiencing heat stroke, some individuals develop a long-term increased sensitivity to heat, making them more vulnerable to heat-related illnesses in the future 1. This residual heat sensitivity occurs because heat stroke can cause damage to the hypothalamus, which controls body temperature, leading to impaired sweating responses and reduced ability to dissipate heat efficiently.

The severity of the original heat stroke episode often correlates with the degree of residual heat sensitivity, with more severe cases potentially causing more pronounced and longer-lasting sensitivity to heat. People who have had heat stroke should be especially cautious during hot weather, stay well-hydrated, avoid strenuous activity in high temperatures, and use cooling strategies like air conditioning 2. The 2024 American Heart Association and American Red Cross guidelines for first aid also emphasize the importance of immediate active cooling for individuals with heatstroke, which can help reduce the risk of residual heat sensitivity 2.

Some key points to consider for individuals who have experienced heat stroke include:

• Staying well-hydrated to help the body regulate its temperature
• Avoiding strenuous activity in high temperatures to reduce the risk of heat-related illnesses
• Using cooling strategies like air conditioning to help dissipate heat efficiently
• Being aware of the signs and symptoms of heat-related illnesses, such as headaches, nausea, and dizziness, and seeking medical attention if they occur. The 2025 Society of Critical Care Medicine guidelines for the treatment of heat stroke also highlight the importance of achieving a faster cooling rate (≥ 0.155°C/min) to improve survival with good neurologic function long-term 1.

From the Research

Residual Heat Sensitivity after Heat Stroke

• Heat stroke can cause long-term neurologic sequelae, including varying degrees of irreversible brain injury, in approximately 20% of patients 3.
• The prognosis of heat stroke is optimal when diagnosed early and managed promptly, but delayed treatment can lead to poor outcomes, including potential residual heat sensitivity 3.
• Systemic inflammatory response syndrome is thought to be responsible for long-term consequences of heat stroke, which may include residual heat sensitivity 4.
• Heat intolerance can be a residual injury after heat stroke, and individuals who have experienced heat stroke episodes should be tested for heat tolerance 8-12 weeks post-episode to detect possible residual injury in thermoregulation 5.
• Residual heat sensitivity may be related to the severity of the heat stroke, with severe cases more likely to result in long-term complications, including heat intolerance 6.

Factors Contributing to Residual Heat Sensitivity

• Core body temperature and level of consciousness are significant indicators of the severity of heat stroke and can affect the likelihood of residual heat sensitivity 6.
• White blood cell count is also a contributing factor to heat stroke outcomes, including potential residual heat sensitivity 6.
• Other factors, such as old age, low Glasgow Coma Scale (GCS), and prolonged hospital stay, can also contribute to poor outcomes, including residual heat sensitivity 6.
• Previous heat stroke episodes can reflect an underlying cause for heat susceptibility and increase the risk of residual heat sensitivity 5.