Running makes us hot! And yet the most important thing to know about managing your body temperature is that everyone is different. And while average at-rest body temperature is 98.6 degrees across most people, the temps that your body will get up to, while running, varies - usually between 101-103 degrees. For some people, running at 103 will induce symptoms of heat fatigue (light-headed, dizziness), while others will feel normal.

Over time, most runners get to know their own bodies and tendencies. Do you “run hot” or “run cold” ? Some runners switch from shorts to tights in anything under 50 degrees, while other wait for it to get into the low 30’s. For years, there was a guy that ran around Green Lake in Seattle - through the winter - in only a Speedo, so there you go.

In addition to the right apparel, the three main ways to reduce heat fatigue are: acclimatization (gradually building up your mileage in the hot climate), hydration (not just during, but within 24-48 hours before), and in extreme cases, reducing your core temperature prior to effort (including ice baths or cooling-vests or clothing).

Sun protection is critical. With regard to fabrics, keep in mind that the higher the UPF (ultraviolet protection factor) rating, the greater the protection. And while it might seem like breezier fabrics are better, an open knit can let damaging UV rays through. Tight knit, UPF rated fabrics are best suited for sun protection.

  • Sunscreen, always, for exposed areas
  • Sun protective hat or visor
  • Eyewear with UV protection
  • UPF clothing (30 UPF ratings and above are considered best)
  • Bandana with water or ice tied around neck
  • Lightweight, wicking fabrics such as Oiselle HoverFit™ in Flyout® styles

The best plan is always to reduce effort or exposure when necessary. If you feel poorly—light-headed, nauseous, extremely fatigued, have cramps or a headache—those are big-time warning signs to back off the pace.