Regular exposure to extremely cold temperatures might seem like the pursuit of a masochist, but for some it is a pure experience of solace, salvation and enlightenment. What’s more, scientific evidence suggests that if we want to live better for longer, we should all be chilling out.
In the depths of the Finnish winter, when even the animals seem to retreat from the cold and silent pine forests ,you’ll find a figure clad from head-to-toe in a black rubber suit striding out upon a frozen lake. This is Johanna Nordblad. It is -7°F outside, but it makes no difference to Nordblad, a freediver and ice-diving world record holder, for whom swimming among the freezing blackness on a single breath is solace. It is her peace but also her danger. To suffer a lapse in concentration beneath a thick sheet of ice with only the entry hole she sawed for escape is a hazardous, if not easily fatal exercise. The reason for her love of sub-zero risk-taking came, perhaps surprisingly, from a downhill bike accident that she suffered in 2000, when she almost lost her leg. “They had to leave the fracture open for 10 days to avoid necrosis. Both bones of my shin were shattered into little pieces. For three years, the pain would wake me up every single night. That was the reason I started the cold-water treatment. At first, I did not like it, the cold was agony, but slowly I got used to the feeling.”
Nordblad is not alone in developing a fondness for freezing. Fellow freediver William Trubridge regularly makes excursions to the coldest darkest depths, while ice-climber Will Gadd spends much of his time fixed precariously upon vast walls of ice. Although these extreme athletes’ preponderance for the cold goes to levels most others are unwilling to venture to, visit any professional sports training facility today and you’re likely to find an industrial ice-cube machine somewhere on the premises.
Nobody has done more to convince the public of the benefits of cold-shock therapy than 58-year-old Dutchman Wim Hof, the self-proclaimed Iceman and holder of 26 world records. Hof’s exploits in the cold are simply remarkable. In 2009, for example, dressed in nothing but shorts, Hof completed a full marathon above the Arctic Circle in Finland in five hours and 25 minutes, with temperatures close to -4°F. It would be easy to cast him as a freak of nature, but for many years Hof has been proselytizing his cold exposure techniques to thousands of people and with great success.
Through a combination of breathing techniques (what amounts to a controlled hyperventilation), meditation and gradual cold-exposure, Hof and a group trained under his method were able to suppress a bacterial toxin administered under the scientific scrutiny of researchers at Radboud University Hospital in the Netherlands (the extraordinary results were published in the Proceedings of the National Academy of Sciences). Hof believes his method is able to control the body’s autonomic nervous system and thus the immune system by regulating the release of adrenaline. Increasingly, evidence shows that immune responsiveness is heightened, rather than suppressed as many believe, by the so-called ‘fight-or-flight’ response, which is mimicked by the sudden shock of cold immersion.
More recently, Dr Rhonda Patrick, a biomedical scientist and researcher on the aging process, put together an extensive report on the science behind cold-shock therapy to paint a picture of exactly what is happening when we are exposed to freezing temperatures. “One of the most consistent and profound physiological responses to cold exposure is a robust release of norepinephrine into the bloodstream, as well as in the locus coeruleus region of the brain. What makes norepinephrine so interesting is that it’s not only a hormone but also a neurotransmitter and is involved in vigilance, focus, attention and mood.” As Dr Patrick discovered, cold exposure increases norepinephrine up to five-fold in the brain, which suggests that regular exposure could have extremely significant benefits to mental health and performance. It is perhaps the reason why Nordblad is able to dive deep beneath the ice and maintain absolute focus while in the midst of an inherently dangerous environment.
“The cold induces this robust increase in norepinephrine in both mice and humans and is a response mediated by the sympathetic nervous system, the primary purpose of which is to stimulate the body’s fight-or-flight response,” writes Dr Patrick. “Decreased norepinephrine neurotransmission is associated with inattention, decreased focus and cognitive ability, low energy, and poor mood (generally). When norepinephrine is depleted in people by pharmacological intervention, it causes depression.”
The tragic death of Hof’s wife in 1995 was a catalyst moment for Hof’s journey into the cold and the salvation he was convinced existed there. Despite years of having to endure cynicism and scorn from the scientific community, evidence is stacking up on his side. A recent study has shown that long-term cold-water immersion (three times a week for six weeks) in healthy males increased lymphocyte numbers, including cytotoxic T lymphocytes, which are a specialized type of immune cell that kills cancer cells. This would make sense of Hof’s ability to train a randomly selected group of people to withstand a bacterial toxin, while a non-trained group all fell chronically ill. You may not want to risk your life in frozen lakes, or run a marathon in the Arctic Circle with only your boxer shorts for modesty, but there are simple ways in which you can implement cold-shock therapy in your home, namely with a cold shower or ice bath. The question is how cold is cold?
“There does appear to be a temperature threshold for activating the sympathetic nervous system,” explains Dr Patrick. “For example, cold-water immersion at 68°F for one hour does not appear to activate norepinephrine release, whereas one hour at 57°F increased it by 530 percent and also increased dopamine by 250 percent.” Long durations, you’ll be thrilled to learn, aren’t necessarily required for a potent release of norepinephrine: “A long-term study in humans directly compared people that immersed themselves in cold water at 40°F for 20 seconds to those that did whole-body cryotherapy for two minutes at -166°F three times a week for 12 weeks, and found that in both cases, plasma norepinephrine increased 200–300 percent, and this release of norepinephrine didn’t seem to be reduced with habituation to cold.” As the cascade of cold water envelops your body and your fight-or-flight response kicks in, your only option is to attempt to control your breathing and bring your attention inward. As Hof himself says, “To go deep within and confront your inner being is a powerful act. Going deep and developing the willpower is the only way.”