As summer loosens its grip on the northern hemisphere, long days on the beach eating ice cream or splashing in the ocean are gone for most. But for some swimmers, the fun is just beginning.
“The best part is going to Brighton Beach in the fall. Each week, the water is a little cooler than the last. Before you know it, it’s 48 degrees!” Bonnie Schwartz Nolanmanagement, operations and finance consultant, swimming coach and successful English Channel swimmer from New York, account popular science. She has been floating in the cold waters of Brooklyn for more than two decades.
To train for the majority Marathon swimming (swimming over 6.2 miles or 10 km)swimmers need to get used to spending time in the cold, as swimmers are often unable to wear a wetsuit or technical suit to keep warm, and instead must rely on their own bodies.
“Your core body temperature is 98 degrees, so even something like 80 will feel cold after a while,” Nolan explained. To even qualify to swim the English Channel, swimmers must undergo a six hours under 60, or continuous swimming in water less than 60 degrees Fahrenheit (about 15 degrees Celsius).
[Related: Swimming is the ultimate brain exercise. Here’s why.]
Open water swimming has even grown to include ice swimmingor swim in water below 41 degrees Fahrenheit (5 Celsius). “For me, it’s all about the challenge,” he says. Elaine K Howleyjournalist and accomplished swimmer, in an interview with pop science. “It’s that uncertainty around ‘I can do it,’ the same way marathon swimming is.” Howley is an accomplished ice and marathon swimmer who completed a ice mile in 2012 and is currently training for his second.
Some anecdotal “wellness” Adherents of regular cold water immersion have made claims including weight loss, better mental health, and increased libido, but what about the hard evidence?
A scientific review published today in the peer-reviewed journal International Journal of Circumpolar Health finds that soaking in cold water can cut down white adipose tissue (WAT) in men and reduce the risk of disorders such as diabetes, but other benefits of ice swimming are inconclusive.
The authors analyzed 104 scientific studies and found an additional impact on brown adipose tissue (BAT). The difference between the two is that WAT stores energy instead of burning it like BAT does. Repeated exposure to cold water or air. increases BAT productionwhich is also found in blubber from marine mammals such as whales and seals to help keep them warm.
BAT helps the body burn calories, maintains body heat when exposed to cold temperatures, and also helps the body control blood sugar and insulin levels. It produces heat in the blood when it is cold outside and is found mainly around the neck, kidneys, adrenal glands, heart, and chest in adults. According to the Cleveland Clinic, is brown because fat cells are full of mitochondria, which contain a lot of iron. Iron gives BAT its brown hue.
Exposure to cold water or air also appears to increase the production of a protein called adiponectin by adipose tissue. This is a protein that plays a key role in protecting against insulin resistance, diabetes and other diseases. Consistent with the data reviewed in these studies, repeated cold water immersions in winter significantly increased insulin sensitivity and decreased insulin concentrations. This occurred in both inexperienced and experienced swimmers.
Swimming in cold water also has a great impact on the body and triggers a shock response such as elevated heart rate. Some of the studies reviewed showed evidence that cardiovascular risk factors actually improve in swimmers who have adapted to the cold. However, other studies suggest that the heart’s workload continues to increase. Overall, the authors were inconclusive about the overall health benefits of “the fastest growing extreme water sport”.
“It is clear from this review that there is growing scientific support that voluntary exposure to cold water may have some beneficial health effects,” said lead author James Mercer of UiT The Arctic University of Norway, in a press release.
According to the authors, many of the available studies on the health benefits of ice swimming involved small numbers of participants, often of a single gender, and did not take into account differences in water temperature or whether the water was it sweet or salty. It’s also unclear whether winter swimmers are naturally healthier than the general population.
[Related: How to avoid (and treat) hypothermia.]
“Many of the studies demonstrated significant effects of cold water immersion on various physiological and biochemical parameters. But the question of whether or not these are beneficial to health is difficult to assess. Based on the results of this review, many of the claimed health benefits of regular cold exposure may not be causal. Instead, they can be explained by other factors including an active lifestyle, trained stress management, social interactions, as well as a positive mindset.” mercer added.
The authors note that the swimmers who participated in these studies ranged from elite swimmers or established winter bathers to those with no prior ice swimming experience. Some were strictly ice bathers, but used cold water immersion as a post-exercise treatment.
The review also found a need for better education about the health risks that can arise from submersion in ice water. These include hypothermia if a swimmer is in the water too long or jumps in without acclimatizing, as well as heart and lung problems related to cold shock. Simply jumping into cold water is very dangerous, and it is best to start ice swimming slowly over a period of time.
If swimming in icy waters sounds like fun to you, Howley and Nolan recommend taking increasingly longer dives in cooler waters to acclimatise. Nolan also took cold showers, slept with the windows open and a lighter blanket, and wore a vest instead of a coat outside to help his body acclimate to the freezing temperatures.