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What is hot/cold therapy?
Heat therapy is the exposure of the entire body or certain parts of the body to extreme heat in a bid to alleviate disease. It was first documented in Ayurvedic medicine where it was used for relaxation and pain management. Cold therapy is exposure to extreme cold also in a bid to alleviate illness. It is common among athletes who use it to relieve sore muscles. The two can be combined, hence, hot/cold therapy or contrast bath therapy.
Though the practice is ancient, some cultures swear by it. In the last 15 or so years, hot/cold therapy has been put under a microscope to investigate whether it is indeed a viable form of therapy. Owing to the low incidence of common colds in Finland, a country where hot/cold therapy is quite popular, scientists are especially interested in investigating its effect on the immune system in relation to viral infections. And, on account of the ongoing global pandemic which is caused by a virus belonging to a group of viruses notorious for causing the common cold, a review of the findings is warranted.
The most landmark findings
A German study investigating the thermal effects of fever found significant benefits. Twelve volunteers were recruited and placed in hot water baths until their core temperatures were 39 degrees Celsius. The authors were investigating the effects of inducing a fever to the body’s immune system. They found that hot water baths enhanced the response of monocytes, a type of immune cell that is critical in fighting off viruses and bacteria.
A study conducted in Australia also showed similar results. The investigators recruited 50 patients, and half of them took regular sauna baths while the other 25 did not. The investigators followed up the two groups of patients for three months. The study found that the group that took regular sauna baths reported a lower incidence of common cold in those three months.
Another well documented study alternated cold exposure to heat exposure in patients with the flu. It found that brief exposure to cold consistently increased immune response to the flu thereby reducing its duration and severity. What’s more, they reported better results when subjects were exposed to heat first. Heat exposure was in the form of hot baths or intense exercise. The study successfully debunked the myth that cold exposure worsened the flu. In essence, brief exposure to cold was shown to be beneficial.
Finnish saunas are especially notorious for pushing the limits of hot therapy. They are said to heat up close to boiling point and raise the core temperature to 39 degrees Celsius. They raise the temperature of the skin to 42 degrees Celsius. A Finnish study investigating the effects of Finnish saunas to the immune system was recently published. The investigators found that increasing the body temperature then cooling the body fast with a cold/ice bath increased the number of circulating white blood cells.
While hot/cold therapy has been shown to boost the immunity, particularly against viruses that cause common cold, there is no evidence that this form of therapy is beneficial to patients with COVID-19. In pregnant women, extreme forms of hot/cold therapy are extremely unsafe.
Is hot/cold therapy safe for pregnant women?
Hot therapy is particularly dangerous for pregnant women. While a quick hot shower is tolerable, long sauna sessions where the temperature is extremely high have been shown to negatively impact the unborn child. Heat from the mother can be transferred to the unborn child leading to several problems. The human fetus is still developing and cannot regulate heat as adequately as an adult. Studies have shown that exposure to extreme heat while pregnant can lead to spontaneous abortions and birth defects.
Even so, you can leverage the power of hot/cold therapy to boost your immunity without putting your unborn child at risk. Yes, you should avoid extremes of heat at all cost. But there are 3 strategies that are extremely safe. One, alternate between hot and cold water while showering. Keep it brief and ensure the cold water is not too cold and the hot water is not too hot.
Second, perform moderate exercises. Exercise increases the core body temperature and acts in a similar manner as hot therapy. Do not push yourself too hard, a brisk walk is sufficient. Taking a cold shower afterwards will act as a fast cool down and lead to added benefits.
Finally, do not treat any fever with over-the-counter medication. Fevers are part of the immune response and are the body’s brand of hot therapy. Fevers, especially early on in the infection, have been shown to improve disease outcomes. That being said, having a fever while pregnant is akin to a medical emergency. Thus, you should consult your doctor immediately and follow the treatment regimen they recommend after they have done the necessary tests. Thus, the rule of thumb here is: do not treat a fever yourself, but be sure to consult your doctor immediately.
In summary
While hot/cold therapy has been shown to boost the immunity, particularly against viruses that cause common cold, there is no evidence that this form of therapy is beneficial to patients with COVID-19. At best, it may reduce the chances of getting infected when combined with other solid prevention measures such as optimal intake of immune boosting vitamins, regular hand washing, and social distancing. In pregnant women, extreme forms of hot/cold therapy are extremely unsafe. Even so, simple day to day measures when done regularly, have been shown to have the same effect.
