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Feature Articles: Exercise


Underwater picture of water aerobics classStay active without succumbing to heat

Linda Rellergert, former Nutrition and Health Education Specialist, St. Charles County, University of Missouri Extension


Missouri’s summertime combination of high heat and dripping humidity can deter even the most ardent devotees of fitness, prompting all of us to seek the coolness of indoor air conditioning. Total hibernation during hot weather, though, can set one on the path to an inactive lifestyle. A better way to stay active is to work around summer’s heat just as we do winter’s cold.

It is important, however, to pay attention to the weather and the effects of heat and humidity on the body. High heat and humidity can make exercising dangerous because many of the body’s cooling mechanisms can be overwhelmed under these conditions.

The Institute for Aerobic Research recommends adding the temperature and the percent humidity to calculate a heat stress index. If the total equals 160 or less, it is safe to exercise. A total between 161 and 175 indicates caution should be used in exercising. Above that, exercise may be dangerous. For example, if the outside temperature is 90 degrees F and the relative humidity is 70 percent, the total is 160 and conditions for exercise are safe. However, if the temperature is again 90 degrees F but the humidity is 90 percent, the total is 180, which means dangerous conditions for outside exercise.

Hot, humid weather may result in heat exhaustion or heat stroke. Heat exhaustion usually starts with dehydration. Symptoms are profuse sweating, cool and moist skin, rapid and weak pulse, weakness, dizziness, headache and nausea.

Heat stroke occurs when the body has lost the ability to cool itself. Signs are hot, dry, flushed skin, rapid and pounding pulse, elevated blood pressure and deliriousness.

To prevent heat-related injuries:

  • Acclimatize slowly to heat conditions. Go out in the cooler times of the day, gradually increasing the amount of time and temperatures in which you are active.
  • Wear lightweight, loosely woven or airy clothing that is light in color as well.
  • Drink plenty of water before, during and after activity to prevent dehydration.
  • Reduce the intensity of activity to a more comfortable level. For example, walk slower or jog fewer miles.
  • Check the heat stress index before beginning exercise and use appropriate caution if it is over 180.

Here are some ideas for active summer fun:


Get wet...

  • Set up the sprinkler and run through it with the kids
  • Chase the kids with water balloons or squirt guns
  • Take the kids or grandkids to a water park and play on water rides all day
  • Splash in a neighborhood or community pool
  • Play games like Marco Polo, water volleyball, raft races or have an underwater race for diving sticks
  • Go canoeing or tubing on one of many beautiful streams or lakes
  • Wash the car if you have to do something productive


Stay dry...

  • Walk laps at the mall
  • Put some exercise equipment in the cool basement and put it to good use
  • Crank up the stereo and dance
  • Try out a new exercise trend at home — find exercise videos online or rent videos or books from the public library
  • Try out a new exercise or dance class at your local gym or recreation center


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Last update: Monday, July 10, 2017