Staying Safe While Training in the Heat and Humidity
Summer training is where marathons are won, but only if you train smart.
June and July bring the hottest, muggiest miles of your training block. The instinct is to push through it the same way you'd push through a cold morning run, but heat and humidity don't work that way. Your body has to work harder just to stay cool, and that changes everything about how you should approach your runs for the next couple of months.
The good news is that a few simple habits will keep you safe, keep you consistent, and keep you on track for October. Here's what every Hero should know before heading out the door this summer.
Know Before You Go
Before you lace up, check more than just the temperature. Humidity is what makes heat dangerous, because it keeps sweat from evaporating off your skin, which is how your body actually cools itself down. Look at the heat index rather than the temperature alone, and if it's high, treat it as a signal to adjust your run rather than push through it. As a general rule of thumb, if the heat is climbing near 99 degrees and humidity is above 70 to 80%, that run belongs indoors.
Hydrate Before, During, and After
Don't wait until you're thirsty. Get ahead of it by drinking water in the hours before your run, and again in the 15 minutes leading up to it. Carry water or plan a route with fountains so you can keep sipping while you move, and replace electrolytes lost through sweat with a tablet or sports drink, especially on your longer runs. Rehydrating after you finish is just as important as fueling up beforehand.
Time It Right
The single easiest change you can make this summer is when you run. Aim for early mornings before the sun is fully up, or later in the evening once it starts to dip. Steer clear of the 10 a.m. to 2 p.m. window, when heat and UV exposure both peak. If your schedule only allows for a midday run, consider moving that workout to the treadmill instead.
Dress for the Weather
Lightweight, moisture-wicking fabrics in light colors will make a real difference on hot runs. Dark clothing and heavier fabrics trap heat against your skin, working against everything else you're doing to stay cool. Add sunscreen, a hat, and sunglasses to protect against UV exposure, particularly on longer runs where you're outside for an extended stretch.
Adjust the Plan, Don't Abandon It
Heat slows everyone down, including elite runners, and that's normal. If the forecast is brutal, it's smarter to shorten a long run, move a speed workout to a cooler day, or shift a route into the shade than to force your usual pace through the worst conditions. Training through the heat isn't about hitting every number on the plan. It's about arriving in October healthy.
Know the Warning Signs
Dizziness, nausea, confusion, or a sudden stop in sweating are signs it's time to stop your run immediately. Get to a cool, shaded spot, drink water, and cool down with wet towels if you have them. If symptoms don't improve quickly, treat it as a medical situation and get help. Sharing your location with a friend or using a safety app on solo summer runs is a small habit that adds a real layer of protection.
Quick Reminders for Summer Training
Check the heat index, not just the temperature, before you head out
Hydrate before, during, and after every run, with electrolytes on longer efforts
Run early morning or evening, and skip the 10 a.m. to 2 p.m. window
Wear light, moisture-wicking clothing and protect your skin
Adjust mileage and pace on the toughest days instead of pushing through
Know the signs of heat illness and stop right away if you notice them
Run with a buddy or share your location when training solo in the heat
Smart summer training is what gets you to the start line in October feeling strong, not just surviving the season. Take care of yourself out there, Heroes.
