So I saw a thread a while back asking about the benefits of cold showers so I decided to research myself. I saw a lot of websites over the web tout this so called benefit in articles such as (7 benefits of cold showers) and all of them make references to studies that for some reason I can't find. So I decided to crawl through various publications so I can see which benefits are true and which are not. Took me quite a while but I found actual studies to back up or tear down these claims.
The Claim That It Boosts Your Immune System
Immune system of cold-exposed and cold-adapted humans.
http://www.ncbi.nlm.nih.gov/pubmed/8925815
To summarize your immune system gets a small but significant (significant meaning the cold water immersion definitely induced it) boost. This claim checks out.
The Claim That It Helps With Depression
Adapted cold shower as a potential treatment for depression.
http://www.ncbi.nlm.nih.gov/pubmed/17993252
To summarize they found a reduction in some depressive symptoms. The kicker? Practical testing by a statistically insignificant number of people, who did not have sufficient symptoms to be diagnosed with depression, showed that the cold hydrotherapy can relieve depressive symptoms rather effectively. Read that carefully. They themselves claim it is statistically insignificant, and they used subjects who didn't have depression. At the end of their paper they acknowledge there is a potential, but nothing in the science confirms it and more studies need to be done. It might lift your mood if you already aren't depressed. Claim debunked.
The Claim That It Helps You Recover From Workouts Faster, Reduces Soreness, Reduces Fatigue
Effect of Hydrotherapy on Recovery from Fatigue
https://www.thieme-connect.com/ejournals/abstract/10.1055/s-2007-989267
This study used 4 groups: one group passive recovery, one group cold stimulation recovery, one group alternating, and one group hot. The ones in cold stimulation, and alternating hot and cold recovered the quickest from high intensity cycling.
Effect of hydrotherapy on the signs and symptoms of delayed onset muscle soreness
http://link.springer.com/article/10.1007/s00421-007-0605-6
Similar study as above with the 4 groups. This time weighted squat jumps and isometric squats were used. Results where that Cold water, and alternating cold and hot greatly reduced DOMS (delayed onset muscle soreness) and brought back force more quickly than either passive or hot water. These two studies show it works for high intensity cardio as well as weighted resistance workouts. Claim verified.
The Claim That It Increases Testosterone and Sperm Count/ Quality
This is the motherload and what we all want right? The vast majority of articles/blogs and selfhelp websites I found claimed that cold showers give a 491% increase in sperm count as well as increased testosterone. I found that 491% increase quoted quite a lot and increased testosterone mentioned so much, but I managed to track it down to an author named Vijay Kakkar from the Thrombosis Research Institute. The only problem? It was published in a now defunct newspaper, instead of a peer reviewed science journal! Poor ArcBound tried scouring the databases but could not find such a scientific article that so many websites seem to cite.
However ArcBound found a related article
Effects of physical exercise and cold stimulation on serum testosterone level in men.
https://www.jstage.jst.go.jp/article/jjh1946/46/2/46_2_635/_pdf
This article looked at the effects of cold water stimulation before and after exercise. In both groups, after exercise, they found a correlation in increased testosterone due to increase LH (lutenizing hormone) and NA (noradrenaline). This makes sense already. But after the cold water stimulation LH JUMPED UP tremendously yet testosterone fell a small amount of stayed static.
This has two implications. 1) LH works in conjunction with FSH to make sperm, so the sperm quality/quantity claim might be substantiated.
2) LH is supposed to increase sex hormones (both testosterone and estrogen). Yet with this giant spike in LH led to a DECREASE or same level of testosterone. Why? The researchers did not investigate further, but my guess would be negative feedback mechanisms. Increased LH --> increased test and estro --> inhibition of testosterone production. (Estrogen has a negative feedback effect on the hypothalamus in that it causes less testosterone to be made. LH also leads to estrogen because a good portion of the testosterone created from the LH, is converted to estrogen). However this study also had one very huge flaw in terms of looking at cold showers. The cold water stimulation used in this article was merely dipping the wrist into cold water for a total of about 3 minutes! It says nothing about full body immersion or longer lengths of time.
I couldn't find any other scientific studies that looked at testosterone and sperm count, but if this study is anything to go back, sperm quantity is most probably increased from the huge spike in LH, yet the spike in testosterone is either very short and large, or non-existent. Claim neither debunked or verified. There is just no real research on this at all and any website telling you cold showers definitely increase testosterone are straight up lying from a scientific standpoint.
I will research more effects of this when I have time, and post subsequent studies if I find any. But for now, what cold showers can do: might give a slight mood lift (if you are not depressed), boost immune system a bit, recover strength faster from workouts and less DOMS. What they are not proven to do yet: alleviate symptoms of depression in actual depressed people, increase testosterone.
I think future research, if done at all, will lead to some sort of increase in testosterone, after all look at all the batsh!t crazy Russians swimming during Winter. But that is all anecdotal evidence and hypothesis for now.
The Claim That It Boosts Your Immune System
Immune system of cold-exposed and cold-adapted humans.
http://www.ncbi.nlm.nih.gov/pubmed/8925815
To summarize your immune system gets a small but significant (significant meaning the cold water immersion definitely induced it) boost. This claim checks out.
The Claim That It Helps With Depression
Adapted cold shower as a potential treatment for depression.
http://www.ncbi.nlm.nih.gov/pubmed/17993252
To summarize they found a reduction in some depressive symptoms. The kicker? Practical testing by a statistically insignificant number of people, who did not have sufficient symptoms to be diagnosed with depression, showed that the cold hydrotherapy can relieve depressive symptoms rather effectively. Read that carefully. They themselves claim it is statistically insignificant, and they used subjects who didn't have depression. At the end of their paper they acknowledge there is a potential, but nothing in the science confirms it and more studies need to be done. It might lift your mood if you already aren't depressed. Claim debunked.
The Claim That It Helps You Recover From Workouts Faster, Reduces Soreness, Reduces Fatigue
Effect of Hydrotherapy on Recovery from Fatigue
https://www.thieme-connect.com/ejournals/abstract/10.1055/s-2007-989267
This study used 4 groups: one group passive recovery, one group cold stimulation recovery, one group alternating, and one group hot. The ones in cold stimulation, and alternating hot and cold recovered the quickest from high intensity cycling.
Effect of hydrotherapy on the signs and symptoms of delayed onset muscle soreness
http://link.springer.com/article/10.1007/s00421-007-0605-6
Similar study as above with the 4 groups. This time weighted squat jumps and isometric squats were used. Results where that Cold water, and alternating cold and hot greatly reduced DOMS (delayed onset muscle soreness) and brought back force more quickly than either passive or hot water. These two studies show it works for high intensity cardio as well as weighted resistance workouts. Claim verified.
The Claim That It Increases Testosterone and Sperm Count/ Quality
This is the motherload and what we all want right? The vast majority of articles/blogs and selfhelp websites I found claimed that cold showers give a 491% increase in sperm count as well as increased testosterone. I found that 491% increase quoted quite a lot and increased testosterone mentioned so much, but I managed to track it down to an author named Vijay Kakkar from the Thrombosis Research Institute. The only problem? It was published in a now defunct newspaper, instead of a peer reviewed science journal! Poor ArcBound tried scouring the databases but could not find such a scientific article that so many websites seem to cite.
However ArcBound found a related article
Effects of physical exercise and cold stimulation on serum testosterone level in men.
https://www.jstage.jst.go.jp/article/jjh1946/46/2/46_2_635/_pdf
This article looked at the effects of cold water stimulation before and after exercise. In both groups, after exercise, they found a correlation in increased testosterone due to increase LH (lutenizing hormone) and NA (noradrenaline). This makes sense already. But after the cold water stimulation LH JUMPED UP tremendously yet testosterone fell a small amount of stayed static.
This has two implications. 1) LH works in conjunction with FSH to make sperm, so the sperm quality/quantity claim might be substantiated.
2) LH is supposed to increase sex hormones (both testosterone and estrogen). Yet with this giant spike in LH led to a DECREASE or same level of testosterone. Why? The researchers did not investigate further, but my guess would be negative feedback mechanisms. Increased LH --> increased test and estro --> inhibition of testosterone production. (Estrogen has a negative feedback effect on the hypothalamus in that it causes less testosterone to be made. LH also leads to estrogen because a good portion of the testosterone created from the LH, is converted to estrogen). However this study also had one very huge flaw in terms of looking at cold showers. The cold water stimulation used in this article was merely dipping the wrist into cold water for a total of about 3 minutes! It says nothing about full body immersion or longer lengths of time.
I couldn't find any other scientific studies that looked at testosterone and sperm count, but if this study is anything to go back, sperm quantity is most probably increased from the huge spike in LH, yet the spike in testosterone is either very short and large, or non-existent. Claim neither debunked or verified. There is just no real research on this at all and any website telling you cold showers definitely increase testosterone are straight up lying from a scientific standpoint.
I will research more effects of this when I have time, and post subsequent studies if I find any. But for now, what cold showers can do: might give a slight mood lift (if you are not depressed), boost immune system a bit, recover strength faster from workouts and less DOMS. What they are not proven to do yet: alleviate symptoms of depression in actual depressed people, increase testosterone.
I think future research, if done at all, will lead to some sort of increase in testosterone, after all look at all the batsh!t crazy Russians swimming during Winter. But that is all anecdotal evidence and hypothesis for now.
