Missouri's summertime combination of high heat and dripping humidity can deter even the most ardent devotees of fitness and prompt them 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, 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. That is, 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.
Ideas for active summer fun:

Get wet - get out the sprinkler and join the kids in running through it.
Wash the car if you have to do something productive.
Play with water balloons or squirt guns. Go on, it'll be fun!
Go canoeing or tubing on one of our beautiful Missouri streams.
Take the kids or grandkids to a water park and play all day.
Splash in a neighborhood or community pool.
Play games like Marco Polo, water volleyball, raft races, or challenge the kids to pick up soft toys like plastic rings you toss into the pool.
Be active without getting wet - mall walk, put some exercise equipment in the cool basement and use it, crank up the stereo a notch and dance, try a new exercise video or get out an old favorite - and move!