In the dead of winter, the Atlantic Ocean can reach a frigid 37 degrees Fahrenheit. Diving into this water would immediately activate the cold receptors beneath your skin, causing you to experience a “cold shock.” This reaction has the potential to be lethal. First, it triggers an involuntary gasp of air, followed by hyperventilation. This is incredibly dangerous if your head is underwater, as it creates a risk of drowning. Your blood vessels constrict in response to the cold shock, elevating heart rate and blood pressure to levels that can cause heart failure, strokes, or arrhythmia in vulnerable individuals. Within minutes, you may begin to feel dizziness, ringing in your ears, cramping of your hands and feet, and numbness in your extremities. In extreme cases, your nerves could freeze up entirely, inducing muscle weakness and the inability to move. Needless to say, paralysis is the last thing you want to happen while swimming in the ocean.
Despite the risks, thousands of individuals gather each year to submerge themselves in icy waters for charity in an event appropriately titled the “Polar Plunge.” Katie Beatty, a cousin of mine and Cape Cod resident, is a polar plunge enthusiast and posts monthly ice-cold dives on her Instagram, @katie_capecod. “My inspiration is for sure Wim Hof,” she said. “He’s so badass!”
If you are unfamiliar, Wim Hof, also known as the “Ice Man,” is a Dutch athlete known for his superhuman ability to withstand freezing temperatures. His achievements include: running the fastest barefoot half marathon on ice, swimming a distance of 188 meters beneath ice while holding his breath, and climbing Mount Everest wearing only shorts and boots. He attributes his success to the “Wim Hof Method,” which involves gradually exposing his body to low temperatures by taking cold showers. Although his method is scientifically controversial, a study of the athlete in 2011 found that Wim Hof could voluntarily activate his autonomic nervous system to produce a controlled stress response. This finding has caused the public interest in cold water therapy to skyrocket in recent years.
There is increasing evidence that repeatedly experiencing short-term physiological stress could improve health and wellness in the long run.
Researchers are also taking interest in this growing trend. There is increasing evidence that repeatedly experiencing short-term physiological stress could improve health and wellness in the long run. Incidences of infectious diseases in the upper respiratory tract are 40 percent lower in cold water swimmers compared to a control group, according to a 2020 review on cold water swimming. This is primarily due to the increased concentration of white blood cells that occurs during exposure to acute stress. Cold water swimmers generally have lower stress and inflammatory response than an unhabituated control group. This phenomenon is termed “cross adaptation,” meaning that adapting to one stressor helps partially adapt to others. Additionally, the more cold shocks one experiences, the less severe they get.
“I’ve done at least ten cold plunges. I have noticed I can stay in longer, or maybe do a second dunk in winter,” Beatty told me.
Experts say adaptation is reached after about six cold shocks: you become more in control of your breathing, panic less, and your heart rate rises less. Furthermore, the immune cells responsible for inflammation, cytokines, can induce depression-like symptoms by inhibiting serotonin production. By reducing the cytokine response, cold water exposure may be able to biologically mitigate symptoms of depression as well. This was described in a case report of a woman at the University of Portsmouth who was diagnosed with severe depression and anxiety at 17. At 24, when she decided she wanted to be medication-free, researchers suggested a novel treatment plan: weekly cold water swimming. After one month, the patient reduced her medication; after four months, she no longer needed drug treatment. Even a single 20-minute immersion in cold seawater has been shown to improve the mood of young, healthy participants immediately after the swim.
By reducing the cytokine response, cold water exposure may be able to biologically mitigate symptoms of depression as well.
Although the scientific community is still skeptical of cold water therapy, anecdotal evidence tells a different story. According to Wim Hof’s website, over 500 people have “successfully completed” his academy for mastering the Wim Hof Method. Undoubtedly, people who participate in cold water activities swear by its benefits.
When I asked my cousin whether she would recommend her hobby to others, she eagerly answered: “Yes! I hope more will start the more I do it! I hope you will do it with me someday!”
Cold water may not be enjoyable for everyone, but you never know until you try. A cold shower is a pretty brave start.
BMJ Journals (2018). DOI: 10.1136/bcr-2018-225007
Lifestyle Medicine (2021). DOI: 10.1002/lim2.53
Int. Journal of Env. Research and Public Health (2020). DOI: 10.3390/ijerph17238984
Immunologic Research (2014). DOI: 10.1007/s12026-014-8517-0
