It is not a pleasant way to begin the day. Many people have fallen for the temptation to try cold showers, believing that they offer many health benefits.
In the early 19th century, cold showers were introduced for medical reasons. Doctors designed them to be used on prisoners and asylum inmates for "cooling inflamed brains and instilling fear to control impetuous wills".
The Victorians discovered that the shower could also be used to wash people. It was better to have warm water. The shower became a tool that could cause unpleasantness for about an hour and a quarter to become a pleasant, five-minute-long device.
Yet, the old practice of taking a cold bath for its health benefits has not disappeared. In fact, it seems to be gaining popularity. This is especially true for Silicon Valley residents.
What evidence is there?
A large Dutch study found that cold showers were less likely to be used to get sick time.
Over 3,000 people were divided into four groups. They were asked to take a warm shower each day. One group was to finish it with 30 seconds cold water, another with 60 second cold water and another with 90 seconds cold water.
The control group could only take a warm shower. Participants were asked to adhere to this protocol for one month. (64 percent of participants continued to follow the cold-water protocol because they loved it so much.
They found that cold water resulted in a 29 percent decrease in self-reported sick days from work after a three month follow-up. The sickness absence was not affected by the cold water's duration.
Although it is unclear why cold water can prevent people from becoming ill, some research suggests that it could be a way to 'boost' their immune systems. Czechia's study showed that cold water gave an immune system slight boost when it was administered to young athletes three times per week for six weeks. These findings are still being confirmed by larger studies.
The sympathetic nervous system is also activated by cold water, which appears to be an automatic physiological response to events that are perceived as dangerous, stressful, or frightening.
This hormone is released when the body experiences a decrease in heart rate and blood pressure. This is the most likely cause of the rise in heart rate and blood pressure when people are submerged in cold water. It is also linked to health improvements.
It has been proven that cold water immersion can improve circulation. The blood flow to the skin is reduced when cold water is used. The body must warm up to increase blood flow to the skin's surface after the cold water has stopped.
Scientists believe this may improve circulation. One study that examined cold-water immersion following exercise showed that blood flow to and fro muscles improved after four weeks.
Some evidence suggests that cold showers can aid in weight loss. One study showed that cold-water immersion at 14C could increase metabolism by 350%. Metabolism refers to the process whereby your body converts food and drinks into energy. A higher metabolism is roughly equivalent to more energy burned.
Cold showers may have other benefits than physical. One school of thought suggests that cold water immersion can increase mental alertness because it stimulates the fight-or flight response. Cold water applied to the neck and face of older adults has been shown to improve brain function.
Cold showers may be able to reduce depression symptoms. One theory is that a cold shower may help relieve depression symptoms due to its high density of cold receptors.
Even though the reasons are not clear, there is evidence to suggest that cold water immersion and cold showers are good for your health.
Before you turn the cold water tap on at the end of your cold shower, it is important to know the risks associated with cold showers. A sudden shock of cold water can cause severe damage to the body.
Lindsay Bottoms is a Reader in Exercise and Health Physiology at the University of Hertfordshire.
This article was republished by The Conversation under Creative Commons. You can read the original article.