When Is The Temperature Too Hot To Workout Outside?

Summer usually means more time spent outside, and many people enjoy taking their exercise routines outdoors for a change of pace. While change is good, it's important to be aware of the temperature because of the risk of developing heat exhaustion or heat stroke (via Well+Good). Symptoms of heat exhaustion include dizziness, fatigue, headache, confusion, nausea, cramps, and a rapid heartbeat. If you think you're experiencing heat exhaustion, you should get out of the heat immediately, drink fluids (especially electrolytes), remove excess clothing, and take a cool (not cold) bath or shower if possible. It's important to treat heat exhaustion because it could develop into a heat stroke, per WebMD.

So how do you know when it's too hot to exercise outside? The answer is a bit complicated, but Heather Milton, a board-certified clinical exercise physiologist at NYU Langone's Sports Performance Center, told Well+Good that when the temperature rises above 91.4 degrees Fahrenheit, it's getting into dangerous territory.

Consider the humidity

Knowing the air temperature is only part of the equation. Another factor to consider is the relative humidity. Humidity doesn't just make it feel hotter outside — it also causes your body to work harder to stay cool because your sweat doesn't evaporate as quickly as it would in less humid weather. The National Weather Service explains that a temperature of 90 degrees Fahrenheit with a relative humidity of 55% feels more like 97 degrees Fahrenheit. When it's 92 degrees Fahrenheit outside, your body temperature could be anywhere between 98.6 to 105 degrees Fahrenheit. Milton explains that your body doesn't really need to get any hotter than that, per Well+Good.

Medical advisor for Women's Health Dr. Keri Peterson agrees with this notion. She told the publication that when the heat index reaches 90 degrees Fahrenheit, you're better off exercising inside.

If you do decide to exercise outside, you should drink 16 to 20 ounces of water about an hour before your workout. Try to drink four ounces of water every 15 minutes during your session, per Women's Health.