Final answer:
The most reliable indicator to use when determining if you should modify activity for heat is the heat index.
Step-by-step explanation:
The most reliable indicator to use when determining if you should modify activity for heat is the heat index. The heat index takes into account both temperature and humidity to give an indication of how hot it feels to the human body. It is calculated using a formula that combines the effects of air temperature and relative humidity.
For example, on a hot and humid day, the temperature may be 90°F (32°C), but the heat index could be 100°F (38°C), indicating that it feels much hotter. This is important because high heat index values can increase the risk of heat-related illnesses such as heat exhaustion and heatstroke.
Other indicators, such as the local weather report, wet bulb temperature, and humidity percentage, can provide additional information, but the heat index is the most comprehensive indicator specifically designed to assess the impact of heat on the human body during physical activity.
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