Anyone who watches the BBC’s Freeze the Fear with Wim Hof may begin to wonder if there really is “power in the cold shower” as the extreme athlete claims Hof. Huff, who holds a Guinness World Record for swimming under the ice, says that “a cold shower every day keeps the doctor away” by reducing stress and increasing energy levels.
Celebrities participating in the show, including sports presenter Gabby Logan and singer Alfie Poe, are asked to take a 12-degree-Cold shower each day, increasing the shower time over time from 15 seconds to two minutes. Watching the participants’ reaction under the cold shower shows you that it’s not a pleasant experience, at least at first.
There isn’t a lot of research looking at the health benefits of cold showers, so the literature is limited. The largest study with 3,000 participants was conducted in the Netherlands and found that people who took a daily cold bath (after a warm shower) for 30 seconds, 60 seconds or 90 seconds for one month were 29% less out of work with self-reported illness than those who took a bath Just warm. Interestingly, the duration of cold water did not affect pathological absence.
It’s still not clear why cold showers prevent people from getting sick. Some research suggests that it strengthens the immune system. A Czech study showed that immersion in cold water (14°C for one hour) three times a week for six weeks gave a slight boost to the immune system of “young athletes,” the only group tested. However, more research is needed to fully understand the effects on the immune system.
On the BBC programme, Hof suggests that cold water revitalizes the cardiovascular system and thus improves its function. “We go to the gym to work out our muscles, but inside our bodies we have millions of tiny muscles in our cardiovascular system – and we can train them simply by taking a cold shower,” he says.
When you have a cold shower, your heart rate and blood pressure rise. There is some evidence that cold water activates the sympathetic nervous system, which is the part that controls the “fight or flight” response (an automatic physiological reaction to an event perceived as dangerous, stressful, or frightening).
When this is activated, such as during a cold shower, you get a surge of the hormone noradrenaline. This is what most likely causes an increase in heart rate and blood pressure when people are immersed in cold water, and is thus linked to the proposed health improvements that Huff mentioned.
It has also been proven that immersion in cold water improves blood circulation. When exposed to cold water, the blood vessels in the skin constrict (become smaller), reducing blood flow. When the cold water stops, the body has to warm itself, so there is an increase in blood flow as the size of the blood vessels increases due to the expansion. Some scientists believe this can improve blood circulation. A study looking at immersion in cold water after exercise found that after four weeks, blood flow to and from the muscles improved.
In the program, Huff recommends that participants increase the duration of their showers each day. However, the only research study that has explored the duration is the one mentioned previously from the Netherlands. They found that the length of cold showers was irrelevant. Therefore, a 15-second cold shower at 12°C should be enough to experience any health benefits.
Care is needed
Taking a cold shower can be a bit shocking. As mentioned above, it also stimulates the flight-or-fight response which increases heart rate and blood pressure. This can have a negative effect on those with heart disease as it may lead to a heart attack or an irregular heartbeat. If a person has fatty deposits in their arteries, a rapid increase in the heart rate will likely cause some of the plaque to fall off and block the artery, resulting in a heart attack.
Additionally, according to Mike Tipton, an expert in human physiology at the University of Portsmouth, immersion in cold water can be associated with an increase in breathing as well as an increased heart rate. But there is also a “diving response” when immersed in cold water, in which the body automatically lowers the heart rate and instinctively stops breathing (as opposed to the flight or fight responses). This interference can cause heart rhythm disturbances and possibly sudden death. However, this presents a greater risk when immersed in cold water, such as swimming in open water, than when taking a cold shower.
Cold showers are thought to have mental health benefits as well. However, the Dutch research study found no improvement in anxiety from cold showers. But it may reduce symptoms of depression. The reason proposed for this is that people have a high density of cold receptors on our skin and that cold showers activate them and send a massive amount of electrical impulses to the brain, which may have an antidepressant effect.
There has also been research in older adults that suggests that cold water applied to the face and neck is associated with temporary improvements in brain function including improvements in memory and attention.
So Hof’s claim that “cold showers a day keeps the doctor away” has some scientific evidence behind it. However, the extent of the health benefits and the exact causes of them have yet to be determined. Caution should be exercised by those with heart disease.
Lindsey Bottoms, Reader in Exercise Physiology and Health, University of Hertfordshire
This article has been republished from The Conversation under a Creative Commons license. Read the original article.