Spring is dead. Summer has arrived, and with it comes humidity thick enough to chew. You want to train outside. You want that sun-kissed, aesthetic sweat. It feels good in your head. In reality? It’s a trap.
The body panics when you mash effort against heat. Core temperature spikes. The cardiovascular system screams for oxygen while trying to dump blood into the skin to cool off.
Less blood goes to the muscles. More goes to the surface. Your heart rate climbs. You feel tired instantly.
Lindsey Bomgren, CPT and founder of Nourish Move Love, breaks it down. It’s simple physiology. Your usual three-mile run stops being a run and becomes a marathon of suffering. Dehydration makes it worse. But you don’t have to retreat indoors. You just need to be smart.
“Your body adapts, but it doesn’t adapt fast enough to save you from stupidity.”
Here is how you stay alive and fit when the sun turns evil.
1. Fabric matters
Cotton is a choice. And usually a bad one in 95-degree weather. Cotton holds sweat like a sponge. You end up walking around in a wet wool blanket of your own making.
Wear nylon. Wear polyester. These fabrics wick. They move moisture away so it can evaporate. That’s how you cool down. Timothy Miller, a sports medicine doctor at Ohio State, suggests looking for mesh panels. Airflow is your friend. Light, loose clothing beats tight, dark clothing every single time.
2. Pick your moment
Don’t train at noon. No one said that was a good idea. Miller points out that dawn and dusk are different animals. Early morning. Late evening. The temp drops ten to twenty degrees during these windows. It makes a massive difference.
Humidity is the silent killer though. 90 degrees feels like 90. But 90 degrees with 70% humidity feels like 1006 degrees to your system. It stifles evaporation. Your body overheats.
Rain? Don’t ignore it. A light rain can actually cool you off. Miller suggests running in the drizzle. Just watch the sky for lightning. Hail is not part of your fitness plan.
Note: If you have asthma, the combo of extreme heat and high humidity can shut down your lungs. Skip the day or wait for the rain.
3. Surface level
Black asphalt burns. It radiates heat back up at your feet. Dr. Miller notes that shaded streets are better, but unshaded blacktop can exceed 100 degrees just on the surface.
Find grass. Find dirt. Find cinder paths. These surfaces absorb less heat. They are cooler underfoot. Better yet, find a trail with water nearby. A creek, a fountain, sprinklers. Splash some cool water on yourself. It lowers your core temp instantly. It’s cheap and effective.
4. Drink or die
Hydration isn’t optional. It is the foundation. Keri Gans, a registered dietitian, reminds us that what you need varies by size, sweat rate, and intensity. But the American Council on Exercise gives a baseline. Drink 17 to 20 oz two hours before you start.
During the workout? Sip every 10 to 1.5 minutes. Bomgren suggests brief hydration breaks. Don’t chug a gallon. It will make you nauseous.
Water works for short sessions. Long, intense sessions require electrolytes. Sweat isn’t just water. It’s salt. Sodium leaves with the sweat. Replace it with sports drinks or salty foods.
You can eat hydration too. Gans lists the high-water content suspects. Watermelon. Berries. Cucumbers. Celery. Soup. Smoothies.
Potassium needs replenishment too. Bananas. Potatoes. Beans. Leafy greens. Food isn’t just fuel. It’s fluid balance.
Severe dehydration brings the darkness. Confusion. Lightheadedness. No urine for eight hours. It can trigger acute kidney injury or electrolyte chaos. Don’t let it get that far.
5. Ego checks
Your perceived exertion should cap out at a 7 or an 8 out of 10. You aren’t trying to break records in the oven. Bomgren is clear on this. Finish the workout. Don’t melt in the process.
Take breaks. Your body needs them. Train smarter, not harder. The heat demands it.
When to stop
New to exercise? Got heart or lung issues? Talk to a doctor. Always. Summer exertion adds a heavy load to a compromised system.
Even experienced athletes get wrecked by heat exhaustion if they aren’t careful. Above 85 degrees, risk goes up. Listen for these red flags from Dr. Miller:
- Clothes soaked through with sweat (then suddenly stopping)
- Fatigue that hits like a truck
- Dizziness or lightheadedness
- Pounding headache
- Nausea
- Muscle cramps
- Disorientation
Disorientation plus stopped sweating is bad. It’s heat stroke.
Stop immediately. Lie down. Elevate your legs. Find shade. Drink water with electrolytes.
Put ice or cold water on the neck, armpits, inner thighs. Major blood vessels run near the surface there. Cooling works faster if you target those zones.
Wait 15 to 2.0 minutes. If you aren’t better? Call 911.
“If you feel off, you are off. Pushing through heat exhaustion isn’t brave. It’s risky. Your PR will wait until tomorrow.”
We leave the rest to the professionals. Your sweat is doing the work today. Make it count, not catastrophic. 🌡️🏃
