Wear lightweight clothing that does not bind and gives sweat and air room to move. Use coverage, sunscreen, headwear, and eye protection for sun exposure. More importantly, move the run to a cooler time or route and reduce pace or duration: clothing cannot restore evaporation when humidity is high.
Choose for wet behavior
A shirt that feels fine dry can cling, stretch, sag, or rub when soaked. Check shoulder, underarm, chest, waistband, bra-band, and pack-contact areas. Smooth seams and a stable fit often matter more as the run lengthens.
Avoid the “sweat means cooling” mistake
Sweat on skin is not the same as sweat evaporated. Humidity slows evaporation, so the same pace can feel harder and body heat can rise even while clothing is drenched.
Use fewer problems, not more claims
- Lightweight, light-colored clothing.
- A fit that permits movement and airflow without flapping across rub points.
- Sun protection appropriate to exposure.
- Dry clothing ready after the run.
CDC: Heat and Athletes
CDC advises limiting midday activity, wearing loose lightweight light-colored clothing, pacing gradually, drinking more water than usual, and stopping if faint or weak.
Change the session
Use current heat guidance and your health context. Short loops near cooling, shaded routes, an earlier start, lower effort, indoor alternatives, and a firm stop rule provide more safety margin than any shirt choice.