Exercising in the heat and humidity of summer requires some caution to avoid overheating or dehydration. The National Weather Service has created a "Heat Index" (HI) to alert us to dangerous conditions when the heat and humidity are high. Your local weather report may provide a value for the Heat Index in your area. But what do the numbers mean?

If the Heat Index is			Watch out for
	80° - 90°		possible fatigue with prolonged exposure and/or physical activity
	90° - 105°		possible sunstroke, heat cramps or heat exhaustion with prolonged exposure and/or physical activity
	105° - 130°		likely sunstroke, heat cramps or heat exhaustion, possible heatstroke with prolonged exposure and/or physical activity
	130° or above		heatstroke/sunstroke highly likely with continued exposure

It's important to note that the HI values were devised for shady, lightly breezy conditions. Therefore, if you're in full sun, the values can increase as much as 15 degrees.

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