EXERCISING IN THE HEAT

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EXERCISING IN THE HEAT

• Adelphi Universitys Human Performance Laboratory

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How heat effects exercise

• Environmental conditions intensify the work your
  body is doing during exercise
• When muscles contract they produce heat that must
  be released into the surrounding environment to
  keep your body cool
• High heat and humidity do not let the body
  effectively cool itself which puts you at an
  increased risk for developing heat related illness

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Strategies to minimize heat stress and avoid heat
illness

• Wear clothing that allows heat loss and
  evaporation (i.e. loose fitting, lightweight and
  light colored material)
• Reschedule exercise for a cooler time of day
  (i.e. morning, late afternoon/evening)
• Relocate exercise to a shady, breezy site or
  indoors with fans and air conditioning
• Reduce exercise intensity and add rest breaks to
  maintain the same target heart rate that you
  normally work at
• Avoid drinks containing caffeine, alcohol, or
  sugar
• Allow your body to adjust to the heat gradually
• Drink plenty of cool fluids to prevent
  dehydration

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Dangers of dehydration

• Dehydration further raises body temperature and
  greatly increases the risk of developing heat
  illness
• Losing even a small amount of body fluid can
  cause fatigue and make it difficult for the body
  to cope with exercise in warm weather

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Warning signs of dehydration

• Headache
• Thirst
• Weakness
• Irritability
• Premature fatigue
• Muscle cramps
• Nausea

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Signs and symptoms of heat illness

• HEAT EXHAUSTION

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Signs and symptoms of heat illness

• HEAT STROKE
• (serious medical condition)

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• The HEAT INDEX (HI) is the temperature the body
  feels when heat and humidity are combined. The
  chart below shows the HI that corresponds to the
  actual air temperature and relative humidity.
  (This chart is based upon shady, light wind
  conditions. Exposure to direct sunlight can
  increase the HI by up to 15F.)

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Staying hydrated

• Drink before you feel thirsty- once you become
  thirsty you are already dehydrated
• Monitor your urine color- urine should be the
  color of lemonade not apple juice
• Before exercise drink
• 2 cups (16 oz) of cool water 2-3 hrs prior
• 1 cup (8 oz) 10-20 minutes prior
• During exercise drink some cool water or sports
  drink every 15-20 minutes
• After exercise consume at least 2 cups (16 oz) of
  fluids (for each pound of body weight lost)

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How to adapt to the heat

• Getting used to exercising in the heat gradually
  will allow your body to sweat more effectively,
  which cools you off more effectively, and will
  protect you from developing heat illness
• Generally, about 2 weeks of daily heat exposure
  is needed for your body to adapt
• Perform light aerobic activity (i.e. walking or
  biking) each day in the warmer weather gradually
  increasing the intensity

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Those who should take extra caution

• Check regularly on those at greatest risk of
  heat-related illness
• People 65 years of age or older
• Infants and children up to 4 years of age
• People who are overweight
• People who overexert during work or exercise
• People who are ill or on certain medications
• if you are 65 years or older, have a friend or
  relative call to check on you twice a day when
  hot weather advisories have been issued

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For more information

• American Red Cross
• http//www.redcross.org/services/prepare/0,1082,0_
  243_,00.html
• http//www.redcross.org/services/disaster/eduinfo/
  A5032_AreYouReady-HeatWave.pdf
• Dept. of Health and Senior Services
• http//www.dhss.mo.gov/Hyperthermia/HeatPrecaution
  s.html