We just passed summer solstice 2022, and like last summer the temperatures around the US and Europe have been scorching lately. Simply making it through the day can be dangerous. Excessive heat kills lots of people all over the world every year. To say runners need to be careful is an understatement. But we want to run!
By one measure, once you’re running in temperatures above 60°F, every degree warmer adds 1.5 seconds to your perceived effort. That means running in 79°F weather can add 30 seconds per mile to your time verses a 55°F run. At least that’s what it’ll feel like. Others insist you should triple that number and add 90 seconds per mile once at 80°F.
But what if it’s 100°F outside, like it’s been in large parts of the U.S.? Your usual run will be 1-3 minutes per mile slower and will feel just as hard. No matter how you calculate it, running in the heat is tough and potentially dangerous.
The first thing to do when running in hot weather is slow down. Your perceived effort has a whole lot to do with your actual effort. Running the same tempo run at 105°F that you can run when it’s 50°F is a good way to head to the emergency room with heatstroke. Over three or four weeks, however, your body can adapt to running in warmer weather. You’ll sweat more and dissipate heat more efficiently. Some say that training in the heat can help race performance by increasing hot-weather oxygen flow. You just need to be smart and patient as you acclimatize.
Unfortunately, some places aren’t conducive to acclimatizing to the heat—I’m looking at you, Pacific Northwest. That’s because summer temperatures are typically in the 70s or 80s, and only occasionally spike into the 90s or higher for a few days. If this is the case, your body never really gets a chance to adjust to the heat, so consider moving intense workouts to days when it won’t be quite as hot.
What else can you do? Run early in the morning before the temperature climbs into the 90s or above. There’s nothing like a 4:30am run in July to catch the sunrise. Try trail running. Like the basement of a house, you can often find cooler temps in the mountains or on densely wooded trails. Of course hydration is key, before, during, and after a workout. Run with a bottle, a water pack, or be creative and plan your route to hit lots of drinking fountains. No matter what, wear light-colored, fast-wicking clothing and a lightweight hat. I’ve appreciated seeing ultra runner Jim Walmsley rocking a bucket hat during the Western States 100.
After a scorching run, ice packs and even an ice bath can help bring your core temp down. But just laying down under a tree can feel pretty dang good. Best of luck out there!