Exercising in the Hot Weather

heat exerciseNow that the hot weather has arrived, it is time to refresh the guidelines about exercising in the heat.

Because the body produces heat during physical activity, it is important to pay attention to the following guidelines.

Several factors raise the risk of heat intolerance with physical activity:

  • elevated body weight
  • higher exercise intensity
  • longer exercise duration
  • lower fitness level
  • over-dressing
  • being dehydrated
  • medical issues such as diabetes
  • acclimatization (ie: the body adapts t to the heat in about 7-14 days, so the first week of hot weather is more challenging for the body)

Here is what we can do to stay safe and active in hot weather months:

  • Check the heat index: The heat index combines the temperature and humidity – both are a factor in heat stress on the body with exercise.
    • Less than 80 heat index – ok to exercise.  However, since every body is different, you may need a lower heat index for exercise to be comfortable, especially if you are new to exercise or your body weight is elevated.  Bottom line, listen to your body.
    • Greater than 90 heat index – exercise in air conditioning or during a cooler part of the day
  • Exercise in cooler parts of the day – before 10am or after 4pm
  • Exercise in the shade
  • Dress smart – light color, loose-fitting clothing to allow skin to cool
    • DO NOT dress to sweat!  Sweating does not increase fat loss.  Yes you will lose weight on the scale but this weight is not fat, it is water your body needs.
    • Do not use the plastic suits that are advertising to promote weight loss. Again, it is water loss – NOT what you want to lose and increases risks.
  • Hydrate – before during and after activity with water
    • weigh yourself before and after exercise – if you lose more than 2% of your body weight you are considered dehydrated
    • rehydrate slowly and gradually
    • if you have had weight loss surgery,  drink small sips all day long including during exercise
    • if your urine is darker yellow and has a stronger odor, this is a sign you need to re-hydrate
  • Slow down – lower the exercise intensity on hotter, more humid days
  • Take breaks – every 10-15 minutes to allow the body to cool a bit and to hydrate
  • Give your body 7-14 days to acclimate to the hotter weather by lowering exercise duration and intensity.

Know the signs of heat illness:

  • Heat Cramps – Muscle crampsheat illness.  Discontinue exercise and rehydrate. Watch for signs of heat exhaustion. 
  • Heat Exhaustion: (discontinue exercise an seek medical attention)
    • heavy sweating
    • exhaustion
    • fainting
    • vomiting
    • cold, pale, clammy skin
    • watch for signs of progressing to heat stroke
  • Heat Stroke: (discontinue exercise and seek medical attention immediately)
    • hot, dry red skin
    • rapid heart beat
    • confusion
    • loss of consciousness

Always have an indoor plan!  Exercising in air conditioning or with a fan on you is a great alternative on hot days.

Stay Cool, Keep Moving, Be Well,


These blogs are general guidelines. These guidelines apply to patients who are cleared by a physician for the type of exercise described. Please contact your physician with any concerns or questions. Always report any symptoms associated with exercise, such as pain, irregular heartbeats, and dizziness or fainting, to your physician.  

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by | July 16, 2015 · 7:16 pm

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