3. No Evidence For Reduced Muscle Soreness
A cold shower might not be beneficial for recovery from the stress of working out. But what if you could recover faster by reducing muscle soreness?
Several websites I came across referenced a 2010 study analyzing 17 different trials2. To their credit, that study did show a statistically significant reduction in muscle soreness.
The problem is that all those trials used some form of cold water immersion (CWI). As mentioned, total body immersion has not been shown to be the same as a short rinse under a cold shower. So those claims are not justified.
Takeaway: Evidence that cold water immersion reduces muscle soreness does not prove that cold showers have the same effect.
4. It Might Actually Decrease Testosterone
Most claims about increasing testosterone sound too good to be true. Like the idea that you could hop in a cold shower and boost this all-important hormone.
So what does science say about testosterone boosting? The truth is, not much.
Interestingly, there is more information about fertility than testosterone itself. For example, some studies demonstrated experimentally that heat damages the male reproductive system3.
Which some bloggers and bro-scientists recklessly apply to testosterone production. They surmise that if heat is bad, then cold is good. But that’s poor logic without any data to back it up.
One study shows there’s no correlation between cold water and testosterone4. And another study resulted in a 10% decrease in testosterone from cold water exposure5!
Takeaway: There is no real evidence that a cold shower increases testosterone. It may even decrease it!
5. Not An Effective Way To Lose More Weight
Another buzzworthy claim about cold showers is that they help burn more fat. The reason is that studies have shown a correlation between cold exposure and brown fat activation. A special kind of fat that produces heat to keep you warm.
Some studies found that brown fat activation results in a slight increase in metabolic rate6,7. In theory, this could help you lose more weight.
However, there are shortcomings in these studies. For one, they exposed participants to cold temperatures in several ways. Including prolonged cold showers or baths, full-body cold suits, and sitting outside during winter in Sweden! Worse, they were instructed to do this for 1 to 2 hours per day.
Furthermore, the average increase in metabolic rate was just 75 calories per day. To put that in perspective, you burn about ten calories per minute with medium-intensity exercise.
So would you rather freeze your butt off for 2 hours or exercise for 7.5 minutes?
Takeaway: Cold exposure is not a practical way to lose weight.