Play It Heat Safe

Summers in Florida are a brutal mix of heat and humidity. It’s common enough to see 95 degrees F with a “Feels Like” temperature or Heat Index of 105. Sweating doesn’t work so well to cool the body when the air is already saturated with humidity. So how do you play it heat safe?

Blazing Sun

Well, you could stay in climate controlled surroundings until cooler weather arrives, perhaps by December. OR you can follow some proven guidelines, always in accordance with your physician’s recommendations, of course. We all vary in physical condition and limitations, so there is no “one size fits all.” Your heat safe plan is uniquely yours.

That said, there are several excellent guidelines. One I like in particular is the U.S. military physical activity weather flag conditions. Based on outdoor temperatures, this guide shows how much to drink and how much time to rest per hour depending on the degree of exertion. Take a look:

Military Flag System

There are several things to consider when using these guidelines: (1) The temperatures shown are based on the WetBulb Globe Temperature, which takes into account such things as wind speed and UV radiation. (2) This applies only to those who are physically fit enough to endure these conditions. (3) Fluid consumption never exceeds 1 quart per hour (plus or minus 1 cup); too much fluid can be as dangerous as too little. (4) Acclimation: If you spend almost all of your time in climate controlled environments, then go out to play in 95 degrees with 95% humidity and unrelenting sun, you may wilt very quickly. However, the more you’re exposed to these conditions, the more acclimated your body becomes…to a point. (5) These temperatures are NOT the “Feels Like” or Heat Index temperatures. In fact, the WBGTs may be below the actual temperature and far below the Heat Index.

So how do you know what the WetBulb (WBGT) temperature is? Simply check out this NOAA/National Weather Service page and use the map to check out WBGT conditions where you are. It also shows the forecast temperature and heat index, as well as other supporting information. Or you could purchase a WetBulb Globe Thermometer…just Google it.

WBGT current local

Please remember that these are guidelines, so while they apply to most physically fit people, they may not apply to you individually. Even if you’re a beast, I wouldn’t recommend exceeding these limitations. Be smart — don’t risk heat stroke, heat exhaustion, or even just heat cramps. Limit exertion and duration, stay hydrated, stick to the shade as much as possible, wear light weight/light colored clothing and above all, listen to your body.

Still want to learn more about Heat Stress? Check out this OSHA Technical Manual for pages of detailed information. More? Here’s the Army Training Doc on Prevention of Heat and Cold Casualties. More still? Here are even more resources from the National Athletic Trainers’ Association.

One last tip: Here in Florida we have the world’s greatest supply of fresh water springs. Very few things are more refreshing than a dip in cool spring water, especially after a hike or bike ride. And most springs have an abundance of large shade trees nearby. So get out there and enjoy Florida year round by playing it heat safe.

Bonus: Ted-Ed on water and your body: