Effects of cold-water immersion on health and wellbeing: A systematic review
33 comments
·February 4, 2025ninetyninenine
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.
mewpmewp2
Should you also not ask for restaurant recommendations from people? These are also anecdotes.
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.
m3kw9
I tried it for 20 seconds that was it
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"
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.
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.
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.
deepGem
I don't do plunges but do cold showers. They are not the same but cold showers do have one anecdotal benefit for me, I don't feel cold post the cold shower.
My immunity had been pretty good but am not sure if I can attribute that to cold showers. I moved to the bay area in August after nearly a 14 year stint in India. This winter the flu virus got me. I was able to fight it off without a lot of meds, I got sick after nearly 4 years.
So am not sure if my body has good immunity anymore. Overall, I have come to liking cold showers simply because of the post shower feeling.
A hot shower is great while in the shower, not so great afterwards. A cold shower is miserable the first 30 seconds, a pretty good feeling afterwards.
null
refulgentis
I love a good yarn too! Hearing someone describe it can also help motivate you to try it in the first place
> Anecdotal stuff is also useful when there is a lack of science.
Yeah sure, but there is science, the link, and no one is arguing the opposite. The poster doth protest too much
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
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.
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.
gxs
> 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.
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.
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?