Effects of cold-water immersion on health and wellbeing: A systematic review
88 comments
·February 4, 2025gxs
bbstats
Actually socioeconomic status was controlled for. What was not controlled for was pre-existing conditions that might make people have 0 drinks like previous alcoholism, medical conditions where you can't drink, etc.
arisAlexis
Here is a meta study debunking the myth that wine good for you was a myth.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10507274/#:~:text=T...
throw0101d
> Turned out to be people affluent enough to drink wine regularly also had regular access to healthcare and were thus likelier to be healthy (for some definition of healthy)
I'm curious to know about if/how much the positive effects of coffee are about people drinking it in social situations (at a café or after dinner with friends/family).
tofof
I have no idea why you're being downvoted; https://journals.plos.org/plosmedicine/article?id=10.1371%2F... is one of many good studies that show that the 'French Paradox' is little more than socioeconomic effect. The association with lower rates of cardiovascular disease among moderate drinkers shows an effect modification of 1.32 when comparing low vs mid socioeconomic position (SEP), 1.36 for mid vs high, and then unsurprisingly 1.63 for low vs high. This strongly suggests that socioeconomic position has a direct and confounding effect on the outcome measure (cardiovascular disease mortality). The alternative is that socioeconomic position modifies the effect of the treatment (moderate alcohol consumption) itself. This would be a sensible interpretation of an effect modification of a drug administered in the presence/absence of, say, grapefruit juice or DMSO, but severe mental gymnastics would be required to argue for the existence of a mechanism through which socioeconomic class could directly mediate the biochemical effects of alcohol on the body's cardiovascular system.
KennyBlanken
They're being downvoted likely because one study which missed a factor does not make personal anecdotes more valuable, or say anything about the reliability of the scientific method.
The irony of using one study...yeesh.
Also: science is iterative, people. Nobody in the scientific community looks at one study in a vacuum. Follow-up studies seek to confirm, efine, build off of, or come up with a different theory.
Only internet commenters who pride themselves in being "skeptics" do this - because they think skeptics are the smartest people, failing to understand that uneducated skepticism has little value.
When they hear the study had some flaw, they shout "AHA! RESEARCH IS BUNK!" and assume everything that came out of it was useless. Or, more commonly, they don't see some obvious potential flaw not specifically spelled out as being addressed just like a math paper wouldn't explain basic calculus - and assume they've found some flaw that somehow multiple people who have studied in their field for years - missed.
It's like looking at a bowl of cake batter and crying out "that's soup, you're incompetent!" to a chef who has a Michelin star, because it doesn't look or taste like a cake.
gxs
Wow you read way way too much into my comment
Sorry it got you bent out of shape
kazinator
The first time I took an ice bath after a 20 mile run, I was amazed. Not during the bath, but the next day. My legs could walk, hop and skip like it didn't happen.
BugsJustFindMe
I assume you meant like the run didn't happen, but it's funnier to interpret this as like the ice bath didn't happen.
kazinator
Funny or not, that interpretation holds too.
sleno
There's a general principal that stressing the body and mind often begets strength.
Lifting heavy weights stresses your muscles and you get stronger.
Running long distances or short distances intensely stresses your heart and makes your heart stronger.
Doing something you're scared of (public speaking for example) stresses your psyche and makes you stronger.
So sauna and cold plunge both fall into this category of controlled stress that would unsurprisingly have some benefits.
Some of the best athletes of all time use it consistently in their regimen, including LeBron James (40+ and still one of the best players in the NBA).
Even if the cold water was nothing but a sort of pain-endurance test, that's good for your psyche in a similar way doing scary things like public speaking is good for it.
All these things together, I would bet cold plunge is probably good for you. Definitely that it is more likely good for you than bad for you. What do you have to lose? If there's a cold bath around, I'll jump in.
Kirby64
Cold water plunges or cold water immersion have conclusively shown to reduce anabolic signaling [1].
If you’re training to become fit and build muscles, there is definitely a downside. It has benefits in terms of recovery, but that comes at the cost of anabolic response. It makes sense for athletes who have consistent training and need to perform for games, but not for the average person who just wants to look more fit.
sleno
Interesting! Thanks for sharing this, made me revisit the huberman podcast on this topic:
https://www.youtube.com/watch?v=pq6WHJzOkno
He echoes what you said, summarizing: "If your goal is hypertrophy and strength don't do cold immersion until 4 hours or more after your workout".
If we can trust the studies Huberman cites, you can get many benefits from cold plunge and also avoid that post-workout caveat if it's relevant.
Kirby64
I personally would not trust Huberman. Just look at his blatant shilling of questionable products for sponsorship (AG1, being the best example). Look at the studies he cites, I suppose, but there’s plenty of low quality studies that can be cited to try to prove a bad opinion.
aradox66
This is specifically about cold plunge immediately after strength training, there's no evidence this applies as a tradeoff in a more generic way.
Kirby64
Cold water immersion or whatnot immediately after training or exercise is generally when it’s used. Similarly, if you did it right before exercise it would hamper exercise and increase injury risk purely due to lower blood flow through muscles. Could be mitigated by extra warming up, but certainly a pain.
From a practicality standpoint, cold plunging and such are generally done at the same place (and coincident) where you exercise.
It’s similar to aerobic exercise immediately after strength training. Sure, you can do these things far away from each other (cold plunge in morning, train in evening)… but how much time are you going to dedicate to going to the gym?
joemazerino
This systematic review suggests that CWI delivers time-dependent effects on inflammation, stress, immunity, sleep quality, and quality of life, offering potential practical applications for health practitioners considering CWI for stress management and wellbeing support.
Time-dependant is the key here.
corysama
> temperatures ranging from 7°C to 15°C and durations ranging from 30 seconds to 2 hours
Can we get some sort of chart or quick summary of results? Where's the line where temp+time translates to anything significant?
shermantanktop
2 hours? There's an LD50 line in there somewhere.
Cyclone_
Seems like some LLM could do this. If not a chart, at least some summary of the results.
fallinditch
I used to live in a beautiful valley in Wales. When I went jogging in the woods I finished off by jumping from a rock into a waterfall (it was in a wild place, nobody else about).
By first working up a sweat the CWI wasn't too shocking. But what a great feeling afterwards! It's like being high off the best possible drug. Good for your skin too.
Definitely a healthful thing to do if your heart is ok.
smcleod
It should be noted here they're talking about cold water (above freezing) - not ice baths which is what a lot of people seem to think of and is quite a fad in the "sports medicine" industry.
snailmailstare
It's a meta study that potentially includes these as well as other cold water exposure:
> undergoing acute or long-term CWI exposure via cold shower, ice bath, or plunge with water temperature ≤15°C for at least 30 seconds.
liamwire
Yes, but also above 7°C
snailmailstare
Yes, they could work on their grammatical ambiguity when using 'or'. From the studies list, it appears they found no ice baths to study perhaps due to safety concerns.
ninetyninenine
Anecdotal stuff is also useful when there is a lack of science. I hate it when HN people completely dismiss anecdotes and want research papers for everything. Even research papers are dubious.
Please share your personal experiences with cold water plunges! Was it good? Or was it bad? Where did you do it? How did you do it? Do you have a setup at home?
Retric
Tried it for 3 months, noticed zero difference, and stopped.
Now, do you know anything new? No, because anecdotes don’t actually provide meaningful information, we don’t know why we did or didn’t improve. Or in my case if there was some minor benefit or minor harm because I didn’t pay close enough attention etc etc.
meowkit
Anecdotal results are highly dependent on the provider.
The scientific method is supposed to allow someone with no credibility to provide signal through >process< and then gain credibility.
Anecdotes from >a credible< person are very meaningful as they are often a high indicator of signal. A social heuristic outside of rigorous research.
Your results as an anon? Basically useless. On HN? Slightly better than on reddit or facebook. Provide your methodology? Better still, and now youre approaching a research proposal.
The meta discussion around anecdata being useful or not is silly.
Retric
If you want the protocol? Sure water temp 50-55f for 15 minutes 4-6 days a week (generally 5) for 3 months. Water chest height, arms generally above water.
How exactly does credibility matter here? Science is heavily reputation based because there’s so much at stake and so few experiments take place, but with anecdotal evidence I don’t see the credibility of individual datapoints mattering much.
I can’t tell if I minimally influenced my upper respiratory tract infection risk etc, all I can tell is the hassle wasn’t worth a benefit too small for me to notice. And that’s the issue, more than credibility if effect size was large enough to be noticeable to individuals you’d get extremely strong results from scientific studies. Conversely if it isn’t showing up as extremely effective in the literature that’s strong evidence individuals are misattributing their experiences.
yowayb
There are many things (I frankly don't think there's a more specific word for this) like diets and psychedelics where many of us (rigorously minded) are constantly seeking proofs within systems containing sufficient complexity to render conclusions nearly impossible.
hollerith
All five merchants who went to Opal City were never seen again, but don't let that stop you from going to Opal City because anecdotes don’t actually provide meaningful information.
ambicapter
if cold plunges either killed people or revived them from the dead, this would be a great analogy.
mewpmewp2
Should you also not ask for restaurant recommendations from people? These are also anecdotes.
Retric
When someone records the height of a specific mountain we call that a measurement not an anecdote.
If I ask someone if this bar is good, and they say they went to a different unrelated bar and it sucked then I’m going to ignore that as a random anecdote.
m3kw9
I tried it for 20 seconds that was it
Funes-
I don't have a way to do "cold plunges" consistently, but cold showers have been great for me. I have ADHD and am quite anxious and highly sensitive. Whenever I make cold showers part of my daily morning routine, I feel much calmer. Very hard workouts also do wonders, especially if they involve combat sports, which I practice. There's something about overcoming fear of conflict. I guess exposing yourself to extreme cold is akin to that.
meowkit
+1 for cold showers.
Excellent for several things. Personally I recommend them at the end of a normal shower, before bed, to drop your core temperature.
Takes a couple weeks to acclimate, but much easier afterwards, same benefits.
yard2010
Anecdotal - according to the Huberman podcast, cold exposure is better practiced in the morning not before sleep due to its stimulating effect.
dwaltrip
Similar here. Although I’ve taken to just doing an occasional 30-60 seconds of cold water at the end of a regular shower.
Exercise wise, for me, it’s a solid pickleball session. Good intensity cardio, super fun, the competitive striving to win, as well as low stakes, meaningful social interaction, all combined together. Doing pickleball open play (pickup games) a few times a week has been huge for me.
__MatrixMan__
Same here, re: ADHD. The clearest my head ever is is after climbing at my very limit and then taking a cold shower.
nojs
> I hate it when HN people completely dismiss anecdotes and want research papers for everything.
You can point them to this: https://pmc.ncbi.nlm.nih.gov/articles/PMC300808/
mewpmewp2
That is absolutely fantastic and thank you for that.
ninetyninenine
Point them? Them is basically everyone on HN.
askvictor
I do open water swimming through the winter in Melbourne with no wetsuit. Mid-winter it gets to about 8-9C, and I stay in about 20-30 minutes. There's definitely a mental health benefit, probably largely from doing the thing that seems difficult to do, but once you're started it fine. I also notice that at night, after such a swim, I run _really_ hot. Like, don't need a doona, even in the middle of winter in an un-heated and un-insulated house. Overall, I like it, but it's taken years of slow acclimation to get there.
bcoates
Given how absolutely trivial it is to do a randomized intervention study here (you can't do double-blind, but dose-response is easy enough) there's not a lot of reason to care about n=1 results except plausible reports of rare seriously negative outcomes.
If it works, it would be within the resources of an ambitious high school class to prove it. If it doesn’t, "more research will be needed"
refurb
The problem with anecdotes is that the brain is a hell of a drug.
I work in clinical trials and it’s amazing at the list of side effects participants get when they are in the placebo arm.
And it’s not even small numbers. It’s not unusual for 20-40% to have side effects like drowsiness, tingling sensation, muscle pain, jitteriness, euphoria/dysphoria, feeling of being too hot/cold, headache, stuffy nose, tinnitus, frequent urination, diarrhea/constipation, etc.
Now layer that on top of cold plunges where people who do it already have an expectation based on others experiences and boom - you suddenly get tens od thousands of anecdotes about the effects that make it seem like it must be true.
(Note: I’m not making a judgement call on cold plunges, it’s just an example)
KennyBlanken
The person you replied to has such a fundamental lack of understanding of scientific method and logic, you're trying to make a horse drink.
ninetyninenine
Not true. I understand it quite well better then most people and most likely you as well.
You used the scientific method and logic in the same sentence. You're aware that they are completely different right? Science can never prove anything.
m463
Tried (completely) cold showers for a while.
anecdotally:
- the first 15 seconds are the worst, especially cold water on your back.
- it is invigorating. There is a feeling of "being present" that doesn't seem to happen with a hot shower.
- when you get out, the room and toweling off does not feel cold.
- the bathroom mirrors did not fog
I have no idea of the health benefits.
At some point I stopped doing it and then couldn't ever go back.
However, sometimes I do the "james bond shower", which is a hot shower that tapers to cold. mirrors fog, but still somewhat invigorating and easier to do.
I also once stayed in a hotel which had a dual shower stall. I put one to hot, one to cold and would go back and forth. That was very fun and invigorating.
computerdork
Used to do them, and really want to start again. For me, felt more awake than I ever have been. And, your body feels like it's running at its best for a short while - think it's partially because, at least for me, I tense like every muscle in my body before that super cold water hits me. It's like a mini work-out.
econ
In my experience it causes excessive bragging. I had a strong urge to tell people as to assure them of my manly hood. I've seen these tendencies in others too!
My best version is to get in a hot bath, gradually make it even warmer, push it to the limit! Then stick your head over the railing and put a cold shower on it. Convection is a magical thing. It's like washing your brain.
lr4444lr
I really couldn't care. I get cold easily in winter, and it chills me to the bone making me miserable all day, much less via a cold plunge. Not worth the (much needed) mental health benefits.
Sauna? Any day, any time!
nojs
I used to do it every morning in a cold city (water was around 10°C) and it made me feel less cold throughout the day, not more. That was one of the more obvious effects.
ziofill
Have you tried a cold plunge after a sauna? It’s a lot more bearable, borderline enjoyable I would say
KennyBlanken
Exercise hard enough to start sweating and feeling hot. It won't necessarily be immediate, but your base metabolism will rise.
abetancort
Nonsense.
> including a 29% reduction in sickness absence among participants who took cold showers.
Reminds me of back when they claimed wine was good for your health
Turned out to be people affluent enough to drink wine regularly also had regular access to healthcare and were thus likelier to be healthy (for some definition of healthy)
Similarly here, I’m tempted to believe that anyone who does CWI regularly probably lives a healthier lifestyle in general and that CWI is just one element of a robust health routine.
It’d be pretty hard to tease out all this in a study like this. I think in situations like this the approach I’d take is:
See what the science says in terms of theoretical benefits, get some anecdotes from trusted sources, and when the stakes are low like this, give it a shot myself.
That said, noted that some of the other positives seemed to be a bit more directly measurable/observable, eg stress reduced after 12 hrs and things like that.