Heat Stroke Prevention

How Do You Prevent Exertional Heat Stroke (EHS)?

  • Ensure hydration
    • To ensure hydration, athletes can observe the color of their urine, which should be a light yellow or the color of lemonade, or compare to a urine color chart. Their urine should be a color 3 or less.
    • Measure the athletes’ weight before and after each practice to ensure they do not lose more than 2% of their pre-workout weight, assuming they started in a hydrated state. Use the equation: (Pre-exercise weight minus post-exercise weight divided by pre-exercise weight) x 100. By the time next practice begins, athletes should ingest fluids and weigh the original weight. This equation assumes that they do not eat, drink or go to the bathroom during practice.
    • Encourage drinking throughout practice, in the shade if possible, and throughout the day, especially when having multiple practices.
    • As they become used to exercising in the heat they will sweat more and therefore need to replace a greater amount of fluids during the course of the workout.
    • Encourage drinking both water and fluids containing sodium.
      • Learn how to calculate your sweat rate here
    • Wear loose-fitting, absorbent or moisture wicking clothing
      • During hot or humid conditions minimize the amount of equipment and clothing worn.
    • Sleep at least 6–8 hours and eat a well-balanced diet.
    • Practice and perform conditioning drills at appropriate times during the day, avoiding the hottest part of the day (10am–5pm).
    • Work with coaches and administration to follow acclimation guidelines.
    • Slowly progress the amount of time and intensity of conditioning and practices throughout the season.
    • Ensure that proper medical coverage is provided and familiar with exertional heat illness (EHI) policies.
    • Include EHI questions on pre-participation exam to identify high-risk individuals.
    • Make sure your policies and procedures are consistent with the best practice guidelines for preseason heat acclimatization; adapt individuals to heat gradually over 10–14 day period.
    • Educate other medical staff, athletes, coaches, emergency personnel, and parents about EHI and proper hydration.
    • Ensure proper body cooling methods are available, including a cold-water immersion tub, ice towels, access to water, ice, etc. and that this equipment is prepared before practices begin.
    • Establish guidelines for hot, humid weather including; Wet Bulb Globe Temperature (WBGT) readings, time of activity, intensity/duration, equipment issues, rest/water breaks.
    • Be aware of the intrinsic factors (mostly in your control/items you can adjust) and extrinsic factors (mostly outside your control) that cause EHS

    What Puts An Individual At Risk For Exertional Heat Stroke (EHS)?

    Exercise extra caution if an athlete has any of these intrinsic factors or you are concerned regarding any of the extrinsic factors.

    • Intrinsic Factors
      • History of EHI
      • Inadequate heat acclimatization
      • Low fitness level
      • Overweight or obese
      • Inadequate hydration
      • Lack of sleep
      • Fever
      • Stomach illness
      • Highly motivated/ultra-competitive
      • Pre-pubescent
    • Extrinsic Factors
      • Intense or prolonged exercise with minimal breaks
      • High temperature/humidity/sun exposure as well as exposure to similar conditions the previous day
      • Wet Bulb Globe Temperature (WBGT)
      • Inappropriate work/rest ratios based on intensity
      • Clothing
      • Equipment
      • Fitness
      • Peer or organizational pressure
      • Lack of education and awareness of heat illness among coaches, athletes, and medical staff
      • Absence of an emergency action plan, policies and procedures or failure of either to include EHS
      • No or limited access to fluids or breaks during practice
      • Delay in recognition of signs and symptoms associated with EHS

    Look For These Symptoms In Athletes When Exertional Heat Stroke (EHS) Is Suspected:

    The two main criteria for diagnosing exertional heat stroke (EHS) are rectal temperature >105°F (40.5°C) immediately post collapse and central nervous system (CNS) dysfunction (e.g. irrational behavior, irritability, emotional instability, altered consciousness, collapse, coma, dizziness, etc.)

    When observing athletes, look for other signs and symptoms that may indicate they are suffering from EHS:

    • Rectal temperature greater than 105°F (40.5°C).
    • Irrational behavior, irritability, emotional instability
    • Altered consciousness, coma
    • Disorientation or dizziness
    • Headache
    • Confusion or just look “out of it”
    • Nausea or vomiting
    • Diarrhea
    • Muscle cramps, loss of muscle function/balance, inability to walk
    • Collapse, staggering or sluggish feeling
    • Profuse sweating
    • Decreasing performance or weakness
    • Dehydration, dry mouth, thirst
    • Rapid pulse, low blood pressure, quick breathing
    • Other outside factors may include:
      • They are out of shape or obese
      • It is a hot and humid day
      • Practice is near the start of the season, and near the end of practice
      • It is the first day in full pads and equipment

    If an athlete collapses during or immediately after exercise, consider EHS as a differential diagnosis. However, collapse is not required to consider EHS. Many athletes may display CNS dysfunction without collapse and healthcare professionals should still consider EHS as a differential diagnosis.

    What Else Could This Be?

    • Heat exhaustion
    • Exertional hyponatremia
    • Concussion
    • Cardiac arrest

    How Do You Treat An Individual With Heat Stroke?

    Follow these steps to initiate emergency treatment:

    • Remove all equipment and excess clothing.
    • Cool the athlete as quickly as possible within 30 minutes via whole body ice water immersion (place them in a tub/stock tank with ice and water approximately 35–58°F); stir water and add ice throughout cooling process.
    • If immersion is not possible (no tub or no water supply), take athlete to a shaded, cool area and use rotating cold, wet towels to cover as much of the body surface as possible.
    • Maintain airway, breathing and circulation.
    • After cooling has been initiated, activate emergency medical system by calling 911.
    • Monitor vital signs such as rectal temperature, heart rate, respiratory rate, blood pressure, monitor CNS status.
      • If rectal temperature is not available, DO NOT USE AN ALTERNATE METHOD (oral, tympanic, axillary, forehead sticker, etc.).  These devices are not accurate and should never be used to assess an athlete exercising in the heat.
    • Cease cooling when rectal temperature reaches 101–102°F (38.3–38.9°C).

    Exertional heat stroke has had a 100% survival rate when immediate cooling (via cold water immersion or aggressive whole body cold water dousing) was initiated within 10 minutes of collapse.

    Recommended Equipment List

    • Wet Bulb Globe Temperature (WBGT) Device
    • Rectal thermometer
    • Lubricating gel
    • Tub or kiddy pool
    • Cooler with ice
    • Water source
    • 3-4 towels
    • Tent for shade

    When Can The Individual Return To Activity?

    After an EHS episode occurs, there may be physiological changes, such as heat tolerance, that are temporarily, and occasionally, permanently compromised. Long-term complications and morbidity are directly related to the time that the core body temperature remained above the critical threshold. To safely return an athlete to full participation following an EHS, a specific return-to-play (RTP) strategy should be implemented. The following guidelines are recommended for RTP:

    • Physician clearance prior to return to physical activity. The athlete must be asymptomatic and lab tests must be normal.
    • The length of recovery time is primarily dictated by the severity of the incident.
    • The athlete should avoid exercise for at least one (1) week after the incident.
    • The athlete should begin a gradual RTP protocol in which they are under the direct supervision of an appropriate health-care professional such as an athletic trainer or physician.
    • The type and length of the RTP program may vary among individuals, but a general program may include:
      • Easy-to-moderate exercise in a climate-controlled environment for several days, followed by strenuous exercise in a climate-controlled environment for several days
      • Easy-to-moderate exercise in the heat for several days, followed by strenuous exercise in the heat for several days
      • If applicable to the individuals sport: easy-to-moderate exercise in the heat with equipment for several days, followed by strenuous exercise in the heat with equipment for several days