Chris Hemsworth was surfing and swimming in Arctic waters to test the limits of human resilience in what he said was one of the toughest experiences of his career.
Actor Thor has taken on the challenge of swimming 250 yards of an icy Nordic fjord without a wetsuit in pursuit of a longer, healthier life for National Geographic’s new series “Limitless,” which premieres November 16 on Disney+.
To accomplish this feat, he worked with Ross Edgeley, an exercise scientist and extreme athlete, described by Hemsworth as “one of the fittest humans on the planet,” setting world records in swimming.
According to Edgeley, the shock of immersing yourself in icy water has evidence-based benefits for longevity and health.
“Cold water triggers some very powerful survival mechanisms,” he said in the episode. “Controlling the body’s response to cold could have tremendous health benefits in the future.”
While Hemsworth faces other severe challenges in the series, including a Navy-style “sinking resistance” test, he said swimming in the Arctic was the hardest.
“Halfway, it felt like my brain was being stabbed with a thousand knives,” he told Men’s Journal.
Swimming in freezing water is dangerous, especially if you don’t have an expert safety crew, as you can risk hypothermia and death.
But you don’t need to dive in the Arctic to reap the benefits of cold therapy. Research shows that routine exposure to cold in smaller, safer doses can boost metabolism, improve energy and mood, and protect the body from some of the side effects of aging. And if you hate the cold, you may get the same effects just by exercising regularly.
A quick cold shower may help regulate the immune system to prevent illness
Hemsworth may not be in a hurry to jump into the freezing sea again, but by the end of the episode, he’s changed his daily habits to incorporate more cold therapy, like making the last 30 seconds of showers cool.
The routine is based on a 2016 experiment that found that participants who finished taking cold showers took fewer sick days at work.
Between 30 seconds and three minutes at about 50 to 60 degrees Fahrenheit may be enough to see benefits, according to research — no Arctic expeditions required.
Ice baths may relax the muscles, but avoid them immediately after exercise for maximum gains
Hemsworth also swears by ice baths to help with muscle aches, and he’s longtime friend and coach Luke Zocchi, formerly.
Evidence is mixed about the benefits – ice may provide some relief from pain and fatigue, but research suggests that it may not actually improve recovery.
Zucchi said that getting too cold too early can actually slow your muscle gains, by preventing muscles from rebuilding properly from the wear and tear of exercise.
Regular exercise provides similar benefits without the freeze
If you hate the cold, you don’t have to put up with it for your health, because other habits like vigorous physical activity have similar benefits, according to the Cleveland Clinic.
Exercise can help improve blood flow, reduce the risk of chronic disease, and boost mental health, according to the evidence.
To relieve muscle soreness and boost gains without freezing, try active recovery in the form of lower-impact exercises like walking or cycling.