What should you do in the first minutes of a suspected heat stroke case at a marathon?

Extract the runner from the course or finish chute to the medical tent, place them in shade, and remove as much clothing and gear as possible, including shoes, hat, and outer layers. Start whole-body cold water immersion immediately rather than waiting for a full clinical workup. Speed to cooling is the variable that changes outcomes.

Why does cold water immersion work better than wet towels or ice packs for a marathon runner?

Whole-body cold water immersion cools at up to 0.35 degrees Celsius per minute, according to Casa et al. 2007. Wet towels, ice packs, ice sheets, fans, and misting only achieve about 0.03 to 0.08 degrees Celsius per minute. A cooling rate above 0.15 degrees Celsius per minute is considered adequate, a threshold surface cooling alone rarely reaches fast enough for a collapsed runner.

What water temperature and immersion duration should be used for a marathon heat stroke case?

Use the coldest water available, ideally 2 to 15 degrees Celsius, with ice added continuously. Immerse the whole body, shoulders and scalp included, keeping the airway clear. Monitor rectal temperature every 5 minutes and maintain immersion until it falls below 38.6 degrees Celsius, since oral, ear, and forehead readings are not accurate enough to guide the decision.

When should EMS be called during a marathon heat stroke case?

Activate EMS the moment heat stroke is suspected, at the same time cooling begins, not after. This is the Cool First, Transport Second doctrine: on-site cooling starts immediately with the medical tent's own equipment, and transport follows once the runner is stabilized or core temperature has dropped meaningfully.

How large should the finish-line medical area be to handle heat stroke cases?

The finish-line medical area needs enough cooling tub capacity to treat multiple runners in parallel, since heat stroke cases cluster in the same weather window and often arrive within minutes of each other. A tub that allows two people to be immersed simultaneously reduces bottlenecks compared with single-occupant units when several runners present at once.

Can a runner resume activity after apparent recovery from heat stroke?

No. Every suspected case needs medical evaluation and, in most cases, hospital transport, even if the runner feels normal shortly after cooling. Rhabdomyolysis, acute kidney injury, and coagulopathy can develop hours after apparent recovery, so runners should not be cleared to leave without assessment.

How to Manage a Heat Stroke Case at a Marathon: FAQ and Immediate Steps

Q: How do you recognize a heat stroke case at a marathon?

Early signs include a runner slowing abruptly, weaving, becoming confused, or arguing they are fine when their behavior says otherwise. Critical signs are loss of consciousness, seizure, and a stop in sweating despite hot, flushed skin. Most cases cluster in the final miles and immediately after the finish line, when runners have spent their last reserves.

Marathon heat stroke has a well-documented risk window: the final miles, roughly mile 20 to the finish, and the minutes right after crossing the line, when runners have exhausted their thermoregulatory reserve and their guard drops at the same time. Here are direct answers to the questions medical directors and finish-line volunteers ask most.

How do you recognize a heat stroke case?

Watch for a runner who slows suddenly, weaves off their line, becomes confused, or insists they are fine while stumbling. The critical signs are loss of consciousness, seizure, and a stop in sweating combined with hot, flushed skin. Because most cases appear in the last miles and just after the finish, volunteers stationed there need to know these signs cold, not learn them on the spot.

What do you do in the first minutes?

Extract the runner from the course or finish chute into the medical tent immediately.
Move to shade and remove clothing, shoes, hat, and any outer layers to expose skin.
Start cooling immediately, before waiting on a complete assessment. The minutes before cooling starts matter more than the minutes spent diagnosing.

Why does cold water immersion beat wet towels or ice packs?

Whole-body cold water immersion reaches up to 0.35°C per minute (Casa et al., Exercise and Sport Sciences Reviews, 2007), by far the fastest field-deployable method. Wet towels, ice packs, ice sheets, fans, and misting only manage roughly 0.03 to 0.08°C per minute. A cooling rate above 0.15°C per minute is considered adequate, and surface methods alone typically fall short of it, which is why immersion, not sponging, is the standard of care.

What water temperature and how long should immersion last?

Use the coldest water available, roughly 2 to 15°C (36 to 59°F), adding ice continuously rather than letting the bath warm. Immerse shoulders and scalp with the airway kept clear by attending staff. Check rectal temperature every 5 minutes and maintain immersion until it drops below 38.6°C. Removing the runner from the water early risks rebound hyperthermia.

When and how do you coordinate with EMS?

Follow the "Cool First, Transport Second" doctrine (ACSM 2023, IOC/BJSM 2021, Korey Stringer Institute): activate EMS the instant heat stroke is suspected, in parallel with starting cooling, never after it. Cooling begins on-site with the medical tent's own tub. Transport follows once the runner stabilizes or core temperature has come down meaningfully, not as the first response.

How big does the finish-line medical area need to be?

Because heat stroke cases cluster in the same weather conditions, several runners can present within minutes of each other near the finish. The medical area needs cooling capacity sized for that clustering, not for a single isolated case. A tub built for up to 2 people in simultaneous immersion reduces the bottleneck compared with single-occupant units when the tent is handling more than one case at once, and a stable structure that stays level on the uneven ground of a finish-line area matters as much as capacity.

Can a runner go back to activity after they seem to recover?

No. Every suspected case requires medical evaluation and, in most cases, hospital transport, even when the runner looks recovered minutes after cooling. Rhabdomyolysis, acute kidney injury, and coagulopathy can appear hours later, so discharge from the medical tent without evaluation is not safe.