Whether you're running a mile or a half marathon, this handy infographic can ID the ideal air temperature for your workout goals
Overcast and 45 degrees might not be the sort of weather most folks dream about, but it doesn't get much better for an outdoor run. In fact, when researchers from the University of Tulsa examined the 25 fastest performances at different distances, along with the temperature that day, perfect running temps for hovered between 73.4 and 49.4 degrees. A comprehensive study out of France analyzing the collective finish times at six major marathons over 10 years also found that 44.2 degrees is ideal for women churning out the best performances.
What gives? The longer you run, the cooler you want it to be. That's because running generates heat in the body, which then dissipates through sweat. "When it's warmer, your body's ability to dissipate heat can be compromised," says Angela Hillman, Ph.D, an exercise physiologist. "The cooler the temperature, within reason, the more heat your body can give off to keep you from overheating," says Hillman."You cannot lose heat to your environment when it's warm as you would if the temperature were lower. You store it internally and this can cause you to overheat." (A pre-run slushy to 'pre-cool' before exercise in warm weather can help: The idea is that ice increases your core temperature capacity—cooling you down so you have more time before you would reach a too hot temp.)
But colder isn't necessarily better."When it's much colder, your muscles are working harder to produce energy, so they're more easily fatigued," Hillman explains. Plus, fitness plays a role: "The more fit you are, the better your body is at thermoregulating," Hillman says.
And even if the thermometer is at a perfectly cool 45 degrees, "the outdoor temperature will feel about 15 to 20 degrees warmer than it actually is while you're running, depending on humidity and strength of the sun," explains Jason Fitzgerald, a USA Track & Field certified coach and founder of Strength Running. So, even at the perfect temp, you are going to sweat.
The bottom line: Don't worry too much if the mercury is a touch higher or lower. You can mimic the ideal temp with clothing and cooling tricks. But before you head out on your next run, bookmark these stats to help better prep yourself.