By Dr. Mercola
When you're stressed or just finished up a hard workout, jumping into a warm shower probably seems only natural. The warm water promotes blood flow to your skin, helping to soothe tired, achy muscles and helping you to relax. However, there may be good reason to turn the faucet to cold when you shower,both after a workout and on an intermittent basis.
Exposure to cold temperatures via cold water and ice baths, otherwise known as cold water immersion or "cryotherapy," is a popular technique among amateur and professional athletes, but it may offer health-boosting benefits for virtually everyone.
Why Take a Cold Shower After Exercise?
Cold works by lowering the damaged tissue's temperature and locally constricting blood vessels. Using targeted cold therapy, such as an ice pack, immediately after an injury helps prevent bruising and swelling from the waste and fluid build-up. Cold also helps numb nerve endings, providing you with instant, localized pain relief.
On a whole-body scale, immersing yourself in a cold tub of water brings down your heart rate and increases your circulation, minimizing inflammation and helping you recover faster. In fact, cold-water baths appear to be significantly more effective than rest in relieving delayed-onset muscle soreness, which typically occurs one to four days after exercise or other physical activity.
In one study, after analyzing 17 trials involving over 360 people who either rested or immersed themselves in cold water after resistance training, cycling or running, researchers found the cold-water baths were much more effective in relieving sore muscles one to four days after exercise.1 Just how cold does the water need to be?
In this case, most of the studies involved a water temperature of 10-15 degrees C (50-59 degrees F), in which participants stayed for about 24 minutes. Some of the trials involved colder temperatures or "contrast immersion," which means alternating between cold and warm water.
This study did not show a significant benefit compared to rest for contrast immersion, but some experts do believe that alternating hot and cold water helps drive oxygen and nutrients to your internal organs, while encouraging detoxification. Research also shows it may help reduce pain and speed recovery by decreasing blood lactate concentration.2
Cold Water Might Increase Your Body's Tolerance to Stress and Disease
Ever since reading Tim Ferriss' Four Hour Body last year, which first introduced me to the concept, I have been experimenting with this concept. I now go into the shower without allowing it to warm up. I also jump in the ocean without a wet suit on when no one else is in the water. I have found that if I hold my breath it really helps adjust to the shock and I rapidly acclimate to the cold. I have come to enjoy it and now view it as a healthy stress very similar to exercise.
Exposing your whole body to cold water for short periods of time is used to promote "hardening." Hardening is the exposure to a natural stimulus, such as cold water, that results in increased tolerance to stress and/or disease. This was demonstrated by a study involving 10 healthy people who swim regularly in ice-cold water during the winter.3 Following exposure to the cold water, researchers noted a:
- "Drastic" decrease in uric acid levels: High levels of uric acid are normally associated with gout, but it has been long known that people with high blood pressure, kidney disease and people who are overweight, often have elevated uric acid levels. When your uric acid level exceeds about 5.5 mg per deciliter, you have an increased risk for a host of diseases including heart disease, fatty liver, obesity, diabetes, hypertension, kidney disease and more.
- Increase in glutathione: Glutathione is your body's most powerful antioxidant, which keeps all other antioxidants performing at peak levels.
Can Cold Water Help You Burn Fat?
Drinking cold water is known to speed up your metabolic rate, as your body must work to raise the temperature of the water. But cold showers and other types of cold-water or ice therapy may also help boost your fat-burning abilities.
Tim Ferriss also reviews the concept of activating your brown fat to boost fat burning by exposing yourself to frigid temperatures. He claims you can increase your fat burning potential by as much as 300 percent simply through adding ice therapy to your dieting strategy. This is based on the premise that by cooling your body, you're essentially forcing it to burn much more calories by activating your brown fat.
Brown fat is a heat-generating type of fat that burns energy instead of storing it, acting more like muscle than fat. Research has shown that brown fat can be activated to burn more fat by cooling your body.4 Ferriss' suggestions, from easy to 'hard core,' include the following. If you want to give his technique a try, make sure you advance slowly. It may be inadvisable to go straight to the ice bath if you're not used to frigid temperatures:
- Placing an ice pack on your upper back and upper chest for 30 minutes per day (you can do this while relaxing in front of the TV for example)
- Drinking about 500 ml of ice water each morning
- Cold showers
- Immersing yourself in ice water up to your waist for 10 minutes, three times per week. (Simply fill your tub with cold water and ice cubes)
Most studies on cold water immersion report benefits with minimal or no side effects, so if you're willing to spend 20 minutes or so in a cold tub of water, this may be another simple and inexpensive tool to support optimal health and longevity. Of course, common sense is advised. When you immerse yourself in cold water, it will shock your body to some degree so you need to make sure the water is not too cold, and that you do not stay in it for too long. As always, listen to your body and work up to the more advanced ice-therapy techniques gradually.