If you’ve spent even one summer in Kansas City, you know that humidity can make all the difference between a hot day and an unbearably hot day. An 80⁰ degree day with 40% humidity feels like 80⁰, but 80⁰ with 90% humidity feels like 86⁰. And this is never more true than when you’re running.
Worse still, the difference between the actual temperature and the heat index (the “feels like” temp), just keeps increasing as the days get hotter. For KC Express runners, knowing how to deal with humidity is key to a safe and fun summer.
Know How Humidity Affects Your Body
Whatever the outdoor temperature, when you run, your core body temperature rises. This isn’t a problem on cool days, or even warmer days with low humidity. Sweat carries excess body heat to the surface of your skin, and when it evaporates, you feel cooler. But on humid days, your sweat can’t evaporate, so the heat is trapped inside your body.
As your temperature rises, your body focuses on survival. Blood flow shifts to your internal organs and skin, leaving less for other body functions. You may experience nausea, shallow breathing, and an elevated heart rate.
If you continue pushing yourself, your brain temperature will increase. You’ll have less control of your form and footing. You may also become disoriented and unable to evaluate your own body temperature. In fact, when you’re overheating, you’re likely to feel chills and goosebumps.
Recognize the Signs of Heat Exhaustion
Anyone can overheat in hot, humid conditions, but if you’re especially fit, fast, or used to the heat, you may be at greater risk. All of these factors increase sweat rates, and the more you sweat, the more likely you are to overheat. Body size, age, and sweat content also affect how you handle heat and humidity.
Since everyone responds differently, it’s important to pay attention to how you feel in different temps to get a sense of your own limits. Watch for these early warning signs of heat exhaustion and heat stroke:
- Nausea
- Dizziness
- Headaches
- Tingly Skin
- Confusion
If you experience any of these symptoms, stop running right away – even if you haven’t reached your goal mileage or the finish line.
Beat the Heat
As the summer heats up, run in the early morning or the evening to avoid the hottest part of the day. Then follow these tips from Runner’s World and the RRCA to make your runs as safe and pleasant as possible:
- Hydrate properly
- Run in the shade and avoid the blacktop (it absorbs more heat)
- Take walk breaks
- Slow down – run by feel rather than pace
- Wear light-colored, breathable clothes and a visor (to shade your face, but still let heat escape)
You may also want to try pouring water over your head or carrying a washcloth to wipe sweat off your skin. And, if you’re running alone, it’s always a good idea to carry ID and let someone know where you’re running and when you’ll be back. This is especially important in hot, humid conditions. Finally, if you’re absolutely determined to run hard on a hot, humid day, it’s probably best to opt for air conditioning and a treadmill instead of hitting the streets.
By Meredith Lai
KCE Bonus: When it’s hot, we have a cooler full of icy-cold washcloths for the Saturday run group. Grab one, wring it out a bit, and bury your face in it. Nothing feels so good after a hot run! When you’re done, toss it back in the laundry basket for next week.
This website contains general information about running, walking, and fitness, and should not be construed as medical advice. You must not rely on the information on this website as an alternative to medical advice from your doctor or other professional healthcare provider.