Taking a refreshing dip can be a fun way to cool off when it's hot outside, but the water doesn't protect the human body from heat-related dangers including dehydration, sunburn and even heat stroke.
When American long-distance swimmer Fran Crippen died during an international swimming competition in 2010, the heated water was found to have played a role.
The water temperature in the United Arab Emirates that day was reportedly in the mid- to high 80s F, with several other swimmers requiring heat exhaustion treatment after the race.
Crippen's death brought new awareness to the dangers of swimming in high temperatures and highlights just one of the threats that can befall swimmers enjoying the water during the warmer months.
Heat exhaustion and heat stroke
Heat stroke, which is rare among swimmers, may have killed Crippen, due to the excessively warm water and high air temperatures during the race.
“It was such a blow to the sport that it led to an overhaul of lowered limits for open water racing,” said Kathleen Wilson, primary instructor at SwimCalm and a long-time marathon swimmer.
An average of more than 600 people die annually in the United States as a result of extreme heat complications, according to The Centers for Disease Control and Prevention.
“The comfortable temperature range is much smaller in the water than it is on land,” Wilson said.
“Once the water begins to exceed the mid-80s, especially with corresponding warm air temperatures, it can become too hot if moving around in a lap swimming or training session,” she said.
Symptoms to look out for include cool, moist and pale skin; headache or nausea; a sensation of overall weakness; dizziness and mental confusion; and rapid, shallow breathing, according to Inland Empire Swimming.
Any swimmer experiencing the above or additional symptoms of heat exhaustion, which can escalate to heat stroke, should seek medical attention immediately.
Not drinking enough water before and during a swim can quickly exacerbate the effects of heat exhaustion and heat stroke, according to experts.
“The biggest issue people forget is that they are sweating when they are working out in the water,” said Carolanne Caron, a swimming/water safety expert and head coach at Winning Swimming.
Caron suggested that parents or supervisors ensure that children are often rehydrated, have frequent restroom breaks and take breaks from swimming.
Despite being surrounded by water, maintaining proper hydration is essential when swimming because the body still perspires.
“This can be dangerous both for kids who play outside in the pool all day and competitive swimmers who do long and challenging workouts,” said Emily Long, a health and safety expert with SafeWise.
Experts say that most people don't realize their level of fatigue after a swim in warm water until after they stop swimming.
Inland Empire Swimming recommended drinking lightly flavored drinks with electrolytes, like Gatorade, to stay properly hydrated, while avoiding alcohol, carbonated or sugary drinks.
Being in the water won’t protect skin from sunburn or the risk of skin cancer. Experts agree that applying sunscreen just once before a swim is simply not enough, because it wears off over time.
“The coolness of water will make a swimmer less aware of a growing sunburn,” Wilson said. “While reflection of sunlight is more apparent on the beach, it can occur in the water as well."
The American Academy of Dermatology recommends reapplying sunscreen at least every two hours to remain protected or immediately after a swim or excessive sweating occurs.
For long-distance swimmers, re-applying sunscreen can be impossible once it wears off, so using an alternative like Balmex can be necessary, said Wilson.
Traditionally used to treat diaper rash, Wilson said the key ingredient of zinc oxide makes Balmex a useful sunscreen.
Its stickiness and adherence to the skin for lengthy periods provides swimmers with adequate sun protection, she said.
Exposure to bacteria, parasites
Swimmers may be unaware of the dangers of toxic algae, bacterial growth and parasites that thrive in warmer waters.
There's also an extremely rare risk of exposure to Naegleria fowleri, a deadly brain-eating amoeba found in bodies of warm freshwater.
“Giardia and cryptosporidium are two-well known [illnesses that impact the intestines]," Wilson said.
According to the Mayo Clinic, giardia infection causes cramps, bloating and watery diarrhea. The microscopic parasite that causes it can be found in various parts of the world, particularly in places with poor sanitation.
The CDC reported outbreaks of cryptosporidium in American pools and water playgrounds from 2014 to 2016. To avoid crypto infections, parents are advised to encourage children not to swallow water during a swim.
For more safety and preparedness tips, visit AccuWeather.com/Ready.