A cold bath after a hard workout is the preferred method of recovery among athletes. Despite the less than pleasant thought of being submerged in cold water, many athletes swear by the method. On the other end of the spectrum, you’ll find people who swear that a hot bath is far more effective. It could boil down to personal preference but what does the science say?
According to the current theory, a cold bath helps the recovery after a workout by constricting blood vessels to avoid lactic acid building up on the healing muscles. It also slows down the heart rate and may provide better circulation, which lowers the amount of inflammation and as a consequence, leads to less pain and a faster rate of recovery. The main pain relieving effect of cold water is instant because it numbs sore muscles fairly quickly. A cold water bath is reported to lessen the severity of DOMS, specifically, when the temperature of the water is at roughly 55°F.
On the other end of the debate, those against the cold water bath method bring up some valid points. The first one is regarding lactic acid. Opponents to the method claim the theory that constricting blood vessels to prevent the build up of lactic acid doesn’t make much sense from a physiological stand-point. Muscles produce lactic acid in response to strain and the blood flow carries lactic acid away so constricting blood vessels would hinder the process of lactic acid leaving the muscles. Furthermore, lactic acid is not responsible for sore muscles. It creates the burning sensation we feel during the workout as we’re straining our muscles but the post-workout soreness is caused by micro tears in the muscle and the inflammatory response. So, regardless of whether lactic acid stays on the muscle or not, it’s still likely to be sore the next day.
The second point involves inflammation. While reducing the inflammation with cold water can help numb the pain, it may extend the recovery time. Inflammation, although painful, is needed for healing. It occurs when white blood cells travel to the site of the micro tears and start the healing, promoting muscle growth in the process. The saying ‘No pain, no gain’ seems to be entirely accurate in this case. However, too much inflammation is not good either so despite hot water being relaxing and having benefits, so there could be an argument made against that method too.
So, which method is the best: hot or cold?
Research says that both are. Cold water and hot water baths each come with benefits and drawbacks. The studies show that the results change depending on what type of exercise was performed and how intense it was. Hot water baths can be effective for pain relief after light workouts when there isn’t much muscle tearing. It can relax tense muscles and prevent mild stiffness. Cold water baths may have more benefits for slightly harder workouts and help lessen the pain of DOMS.
For the more intense workouts, contrast therapy seems to be the most effective. This method consists of spending up to three minutes immersed in cold water then switching to hot or warm water, followed by up to fifteen minutes of resting. Contrast therapy is often used to promote recovery from injury and since intense workouts can cause quite a bit of muscle tearing, the same effect is achieved. Unless you have two bathtubs, this method can appear to be difficult but going from a cold bath to a hot shower will be just as effective.
There are also some studies which indicate that water immersion, regardless of the temperature, has no effect on soreness or recovery time at all. Since there is no method that will cause you to instantly recovery with no soreness, the changes in the effects between doing nothing after a workout and using water immersion may be relatively small. It comes down to what works the best for you and your particular exercise routine. If you’re unsure, try each method after your normal workout and pay attention to pain levels and how long it takes you to bounce back from the workout.
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