It’s 97 degrees in New York City today—looks like summer weather is finally hitting the east coast. If you’re undeterred in your outdoor exercise efforts, more power to you! But before you hit the hot pavement, read up on how the heat affects running performance, speed and rehydration requirements.
“Your performance will suffer in this god-awful heat,” writes Emily Leaman at Be Well Philly, “and you should adjust your pace and expectations accordingly, especially if you want to be safe about it.”
One 2007 study found that (unsurprisingly) the hotter the temperature got, the worse speeds marathon runners clocked. The performance of the fastest runners diminished by nearly 1% for every 5-degrees-Celsius increase in temperature; for slower runners, it decreased by as much as 3.2% per 5-degrees rise in temperature.
Here’s a nifty tool that lets you calculate just how much you should adjust your running pace based on the temperature that day.
As for how to adjust your hydration to the heat, health coach and hot yoga teacher Maura Manzo recommends drinking “half your weight in ounces of water per day,” including 16 to 20 ounces of water an hour or two before a run.
“Rehydrate with the same amount post-workout with water or another electrolyte-replenishing beverage like fresh-squeezed juice, a green smoothie or plain coconut water,” Manzo advises. “Avoid caffeine, alcohol, salty foods and sugary, carbonated drinks that ultimately dehydrate you.”
Runners should remember not to push themselves too hard when the weather’s hot—heat stroke is not a joke!
Be careful, listen to your body and pay attention to any signs that you’re overheated or under-hydrated. If you aren’t sweating or are sweating less than usual, it’s probably a signal that you’re dehydrated. ”Another way to monitor hydration is urine color,” notes Manzo. “The lighter your pee, the more hydrated you are.”
… and don’t forget to wear sunscreen.