Heat, Exercise and Health Risks

Summer Heat and Exercise

Heat during the summer months usually cast high temperatures and humidity, which creates a pretty tough combination for exercise enthusiasts.  The higher temperatures put extra stress on the body and can have serious health consequences if not managed properly.  When your body temperature rises and you begin to sweat, the body’s natural cooling system kicks into action.  As sweat is evaporated  from the skin, heat is also removed from the body, thus cooling it slightly.  However, add humidity to the mix and the water molecules in the air don’t allow for sweat to be absorbed as quickly and thus the body stays hotter longer.

I felt the affects of the heat and humidity a few weeks ago when I decided to do a bootcamp in the park at 2:00 p.m.  It was crazy hot without a cloud in the sky and I was running out of steam fast.  To top it all off, I forgot a water bottle.  That was a big mistake.  Even though I had plenty of water during the day, I should have brought water to have during the workout.  After about 45 minutes, I felt pretty bad and was happier than ever when the workout was done.

I couldn’t get home fast enough just to get a glass of water and jump in a cold shower.   The rest of the day I felt sick, had a headache, body aches, and felt lethargic.  Lesson learned!  Try to schedule your outdoor workouts around the temperature and weather conditions.  If you can’t avoid the middle of the day and have to workout during the hottest times, make sure to plan appropriately.

Drinking water in heatIt’s vitally important to stay hydrated anytime you exercise but always drink a little extra during summer months.  The important thing is that the body is hydrated and has plenty of fluid when you start to heat up and sweat.  Always drink during and after your workout so that you replenish what your body just released.

Another tip to help keep your body cool is by wearing lightweight clothes for your workout.  Choose light colors with a fabric that lets your body breath.

Finally, help protect yourself from a heat related illness while exercising by planning your workout in cooler times of the day.  Early in the morning or later in the early evening is better than high noon to avoid the hottest temperatures.

How heat affects your body

Your body has a built in cooling system, which is awesome.  However when you add humidity to the higher temperatures, sweat doesn’t evaporate so readily from the skin, and that increases your body’s temperature even higher than normal.  When your body gets heated, more blood begins to circulate throughout the body, specifically to the skin.  But when this happens, there is less blood for your muscles,  increasing your heart rate.

Heat-related illness according to the CDC

  • Heat cramps. Heat cramps are painful muscle contractions. Affected muscles may feel firm to the touch. Your body temperature may be normal.
  • Heat syncope and exercise-associated collapse. Heat syncope is a feeling of lightheadedness or fainting caused by high temperatures, often occurring after standing for a long period of time, or standing quickly after sitting for a long period of time. Exercise-associated collapse is feeling lightheaded or fainting immediately after exercising, such as after a race.
  • Heat exhaustion. With heat exhaustion, your body temperature rises as high as 104 F (40 C), and you may experience signs and symptoms including nausea, vomiting, headache, weakness, and cold, clammy skin. If left untreated, this can lead to heatstroke.


There are some great articles regarding how to prepare if you are exercising in hot summer heat and/or outdoors from the Mayo Clinic and from www.betterhealth.vic.gov.

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