When training outdoors throughout the summer athletes should be aware of not only the temperature, but also current humidity level. Taken together, the temperature and humidity level combine to form a heat index. The National Weather Service define the heat index as “…what the temperature feels like to the human body when relative humidity is combined with the air temperature”.
Quick lesson; though sweating can be sometimes be frowned upon by sport coaches who determine players’ fitness levels through sweat loss, sweating is actually a positive adaptation by the body due to exercise.
Sweating allows an athlete to naturally cool themselves off in an attempt to regulate body temperature. This process works through the evaporation of sweat. However, this process becomes increasingly difficult with rising humidity levels. Within high humidity environments the body has the potential to have trouble regulating temperature due to decreased evaporation of sweat.
Athletes will often notice sudden changes in humidity, but may not take into account their regular climate and environment.
How to Use the Heat Index Chart
- Find current temperature (sorry European friends- example is given in Fahrenheit
- Find relative humidity (%)
- Find meeting point
- Determine level of danger
- Adjust exercise as required
Why is all this important? Intense exercise in hot and humid weather will quickly dehydrate and will cause immediate decreases in sport performance as well as a myriad of other adverse signs and symptoms of heat illness, which at its most extreme can be life threatening.
General Guidelines & Tips
- Wear light, loose fitting clothing when exercising
- Consult heat index chart prior to planned exercise
- Hydrate, hydrate, hydrate [cannot be over-emphasized]
- Adjust exercise intensity and/or duration during initial acclimatization period
- Avoid exercise during the hottest hours of the day (typically 12 pm – 3 pm
If you competition schedule dictates that you will need exercise during peak temperature hours within your season- do not avoid exercising during such hours throughout the summer. Instead, gradually increase exercise duration and intensity during these hours.