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Scientists are finding more and more health benefits to having a quick blast of cold water, including boosting your immune system and easing low mood.
Experts say the best results come not from a cold shower or bath but alternating between hot and cold water.
This technique, known as contrast water therapy, involves showering for about 20 minutes, using hotter water for three to four minutes before suddenly switching to cold for one minute and then back again.
Standing under, or sitting in, hot water for several minutes opens up blood vessels in the skin and muscles, improving the flow of oxygen-rich blood.
Switching to cold water for one minute makes the same blood vessels instantly constrict, reducing the flow of blood.
Over a 20-minute period this creates a ‘pumping’ mechanism, where more oxygen-rich blood flows into the muscles and tissues near the skin, while more deoxygenated blood (blood which has deposited its oxygen cargo into those muscles and tissues) is then pulled back through the veins to the lungs, to collect more oxygen.
This has been found to have numerous benefits, including, for example, helping to reduce muscle ache after exercise. During strenuous exercise oxygen-rich blood cannot reach the muscles to match the rate at which oxygen is used. In response, muscles release a substance called lactic acid which causes a painful burning sensation and can delay recovery after exercise.
However, contrast water therapy is thought to help rid the muscles of lactic acid and speed recovery.
The researchers studied 3,000 men and women aged 18 to 65 who were told to turn the shower to cold for up to 90 seconds at a time in the morning.
The British Association of Dermatologists insists there is no research to confirm that contrast water therapy prevents skin ageing.
Hot and cold showers improve circulation and skin ageing is mostly a problem of poor circulation.
Also, the high level of cold receptors in the skin means a blast of cold water can trigger electrical impulses to the brain, which may have an antidepressant effect.
A study of 14 men at the University of Loughborough found those who had an hour-long soak in a 40C bath burned 140 calories on average equivalent to a half-hour walk and had improved control of blood sugar levels.
Researchers said hot baths raise levels of proteins that help regulate blood sugar and said ‘passive heating’ was a potential therapy for metabolic disorders such as type 2 diabetes.
