heat acclimatization

  • Heat and Hydration

    Athletes are at risk for heat-related illness when their bodies are unable to properly cool themselves during physical activity.  The risk of heat illness increases with rising temperatures and rising humidity.   The body normally cools itself by sweating. But under some conditions, sweating just isn't enough, causing an athlete’s body temperature to rise rapidly.

    Several factors affect the body's ability to cool itself, such as:
    • Weather: when the humidity is high, sweat will not evaporate as quickly, preventing the body from releasing heat quickly.
    • Age: children have lower sweat rates, higher heat production, and require more time to acclimate to heat.
    • Larger athletes:  more mass means more energy production and body heat. Fewer sweat glands per surface area, along with additional fat, insulates the body and keep heat internalized.
    • Restrictive clothes and gear limits heat evaporation and increases insulation.
    • History of heat illness

    Other conditions related to risk include obesity, fever, dehydration, heart disease, poor circulation, sunburn, and prescription drug and alcohol use.

    Because heat-related deaths are preventable, it is vital coaches are aware of who is at the greatest risk and what actions can be taken to prevent a heat-related illness or death.

    General Guidelines for Heat Illness

    Dehydration
    Dehydration occurs when the body looses too much fluid.  Dehydration impairs athletic performance whenever body fluid level falls below 98% of normal. The primary cause of dehydration is sweat loss, an essential body process which facilitates the release of body heat into the environment. When athletes don’t replace what they lose in sweat, the physiological function of the body’s heat management system is compromised, placing both the athletes’ performance and physical well-being at risk.

    Heat Exhaustion
    The inability to continue exercise associated with any combination of heavy sweating, dehydration, sodium loss, and energy depletion. Occurs most frequently in hot, humid conditions.

    Heat Stroke
    Occurs when the temperature regulation system shuts down due to excessive heat production and/or inhibited heat loss.  This life threatening situation occurs during activity and effects organ tissues resulting in systemic organ failures.

    Signs, Symptoms, and Actions to Take
    Signs and Symptoms
    Actions to Take
    Dehydration   
    • Thirst
    • Fatigue  
    • Irritability 
    • Nausea
    • Vomiting 
    • Muscle Cramps
    • Loss of Performance  

    Heat Exhaustion      
    • Dizziness   
    • Headache  
    • Nausea   
    • Vomiting  
    • Weakness  
    • Rapid Pulse  
    • Cold, clammy skin  

    Heat Stroke 
    • * Medical Emergency  
    • Irrational Behavior 
    • Drowsiness
    • Nausea   
    • Hot, dry skin   
    • Confused or disoriented 
    • Dangerously high temperature
    Dehydration   
    • Re-hydrate     
    • Stop activity 




    Heat Exhaustion      
    • Replace fluids (re-hydration is critical)
    • Rest in a cool, shaded area until all symptoms have passed.
    • If dizziness continues, lie the athlete down, elevate  their legs, and seek medical attention.



    Heat Stroke 
    • Get out of sun and seek immediate medial attention. This is an emergency, call 911.
    • Cool immediately using ice baths, ice bags, or whatever  is available for you to use.
    * REMEMBER:  Athletes can still be experiencing heat stroke even if most symptoms are absent.  Seek medical attention immediately at the first sign of serious or unusual symptoms.
       
    Steps to Preventing Dehydration
    • Acclimate to the heat over a period of 10 -14 days by beginning to exercise during the hot parts of the day for 10 -20 minutes and gradually increase your exercise time working up to 1 – 2 hours.
    • Be sure to drink plenty of proper fluids during the acclimatization period.
    • Drink fluids containing sodium to keep your urine clear to light yellow
    • If you sweat a lot, or heat conditions worsen, be sure to take in extra sodium during the day with your meals and/or or rehydration beverages containing sodium.
    • When exercising in the heat, cloths should be breathable and allow for proper sweating and evaporation. Clothes that get wet and hold on to the sweat need to be changed regularly.
    • Alter intensity and frequency if exercising in the heat. Always make adjustments as the heat and/or humidity increase.
    • Hydration breaks should be more frequent and longer as the heat and/or humidity increase.