Hot Out? Here's How to Not Overheat on Your Run

Here's the short version: when it's hot, your pace is going to drop, and that's fine. Expect to run 30–90 seconds per mile slower than you would in cool weather, and don't fight it. The better move is to stop looking at your watch's pace field entirely and run by feel — easy should still feel easy, even if the number on screen looks sluggish.

The science here is pretty simple. Heat forces your body to split its effort between two jobs: pumping blood to your muscles and pumping blood to your skin to cool you off. Your heart rate climbs to cover both, so at any given pace you're working harder than you would be in mild weather. That's why effort-based pacing (or heart rate, if you track it) is a far better guide than GPS pace once temps climb.

Hydration matters before you even start. Aim to drink 400–500 ml of water about 1–2 hours before heading out, so you're not starting the run already behind. Once you're moving, sip 150–250 ml every 15–20 minutes if it's a longer effort — small, steady amounts beat chugging a bottle at the halfway mark.

Timing helps too. Early morning runs are noticeably easier on the body than evening ones, because overnight cooling hasn't fully burned off yet and the sun isn't baking the pavement. If you can only run in the evening, just dial back expectations further.

Last thing: know the warning signs. Clammy skin, dizziness, nausea, or suddenly stopping sweating aren't "push through it" situations — they're "stop now" situations. Heat-related illness escalates fast, and no training run is worth ignoring those signals.