Key Exertional Heat-Illness Risk Factors During Exercise, Sports, and Other Physical Activities and Recommended Responses (Actions) for Reducing Physiologic Strain and Improving Activity Tolerance and Safety

Risk factors
    Hot and/or humid weather
    Poor preparation
        Not heat-acclimatized
        Inadequate prehydration
        Little sleep/rest
        Poor fitness
    Excessive physical exertion
        Insufficient rest/recovery time between repeat bouts of high-intensity exercise (eg, repeat sprints)
    Insufficient access to fluids and opportunities to rehydrate
    Multiple same-day sessions
        Insufficient rest/recovery time between practices, games, or matches
    Overweight/obese (BMI ≥ 85th percentile for age) and other clinical conditions (eg, diabetes) or medications (eg, attention-deficit/hyperactivity disorder medications)
    Current or recent illness (especially if it involves/involved gastrointestinal distress or fever)
    Clothing, uniforms, or protective equipment that contribute to excessive heat retention
    Provide and promote consumption of readily accessible fluids at regular intervals before, during, and after activity
    Allow gradual introduction and adaptation to the climate, intensity, and duration of activities and uniform/protective gear
    Physical activity should be modified
        Decrease duration and/or intensity
        Increase frequency and duration of breaks (preferably in the shade)
        Cancel or reschedule to cooler time
    Provide longer rest/recovery time between same-day sessions, games, or matches
    Avoid/limit participation if child or adolescent is currently or was recently ill
    Closely monitor participants for signs and symptoms of developing heat illness
    Ensure that personnel and facilities for effectively treating heat illness are readily available on site
    In response to an affected (moderate or severe heat stress) child or adolescent, promptly activate emergency medical services and rapidly cool the victim
  • With any of these risk factors or other medical conditions25 adversely affecting exercise-heat safety present, some or all of the actions listed may be appropriate responses to reduce exertional heat-illness risk and improve well-being.

  • a As environmental conditions become more challenging (heat and humidity increase) and as additional other listed risk factors are present, the possible actions to improve safety become more urgent. Note that each listed action does not necessarily correspond or apply to any particular or every listed risk factor.