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by Elaine K Howley

August 2, 2019

Doing an open water swim in hot water can be challenging

Plunging into open water is often a refreshing—sometimes even a shockingly cold—experience. But depending on where and when you’re swimming, the water may not feel cool at all. If said hot spot is the site of your next open water race, that makes performing your best all the more challenging, particularly if you’re more accustomed to dealing with cooler temperatures.

Hot water can be more dangerous than cold. Although it might be easier to get into water that’s very warm, heat can kill you faster than cold. In fact, many hospitals now routinely induce hypothermia in patients dealing with certain heart conditions. The macabre mantra in wilderness medicine is “You’re not dead until you’re warm and dead,” which means there’s room to maneuver between being hypothermic and unrevivable.

On the flip side, being too hot can all but literally cook critical components of the brain in short order. This is why high fevers can be such a concern. If the body is too hot and can’t cool itself, that spells trouble with a capital T. It’s harder to recover from hyperthermia than it is to rebound from hypothermia.

Climate change is real, and many swimming locales are getting hotter. If you’re facing down a too-warm waterway this summer, follow these tips to stay safe.

(Note: U.S. Masters Swimming open water races of less than 5 kilometers can’t be held in water hotter than 87.8 degrees and races of 5 kilometers or longer can’t take place in water hotter than 85 degrees.)

Lose the Cap: Because the brain is such a big gobbler of energy, a lot of heat is present—and lost—through the head. By far, neoprene caps retain the most heat, followed by silicone, latex, and finally cloth. If the water is super-hot, consider losing the cap altogether. For people with long hair, braiding it tightly may help keep it out of your face. Because wearing a bright cap is important for safety reasons, consider using a swim buoy to help boaters spot you if you choose to ditch your cap.

Roll Over: If the air temperature is cooler than the water temperature, there’s a readily available way to bring your body temperature down quickly: Simply expose as much skin as you can to the air. This is often achievable by simply rolling over and taking a break to breathe.

Slow Down: A race in hot water is not a fair fight. Change your goal from winning to simply finishing the swim. Come back another time when the water is cooler to see how fast you can traverse the course.

Choose Not to Compete: It’s just swimming, after all. Most of us are paying for the privilege to race, and even if there’s prize money at stake, consider carefully whether risking permanent health issues is worth the result of a single contest. Being hospitalized with heat stroke or worse can certainly put a big crimp in your future swimming endeavors.


  • Open Water
  • Triathlon


  • Open Water
  • Triathletes
  • Triathlon