Heat-Smart Training: Adjust Before You Overheat

Heat adds stress even when the workout is unchanged. The body must send blood toward the skin and produce sweat while still supplying working muscles. Humidity slows sweat evaporation, direct sun increases radiant heat, and protective equipment can trap heat.

Adjust before symptoms appear. Move training earlier or later, reduce pace or interval duration, extend rest, remove unnecessary equipment, and choose shade or indoor conditioning when risk is high. The CDC recommends beginning activity slowly and increasing gradually on hot days.

Acclimatization takes repeated exposure. After time away from heat, reduce the first several sessions and build duration and intensity progressively. Fitness helps, but fit athletes can still develop exertional heat illness, especially when they are sick, dehydrated, taking certain medications, or returning after a break.

Use a buddy system and watch for headache, dizziness, unusual weakness, nausea, confusion, loss of coordination, or collapse. Feeling faint or weak is a reason to stop immediately and move to a cool place. Confusion or altered mental status is an emergency that requires rapid cooling and emergency medical care.

Hydration matters, but water alone cannot make an unsafe session safe. Modify the work, the environment, and the recovery plan together.

Sources:

CDC: Heat and Athletes — https://www.cdc.gov/heat-health/risk-factors/heat-and-athletes.html

NIOSH/OSHA Heat Safety Tool and Heat-Risk Guidance — https://www.cdc.gov/niosh/heat-stress/communication-resources/app.html