from Hacker News

The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial

by drops on 11/16/17, 7:45 PM with 158 comments

• by cyberferret on 11/17/17, 5:19 AM

  We did this in our entire house for about 6 months once when our water heater broke and we couldn't afford to get it fixed quickly.

  UPSIDES: We nearly halved our water bill as all of us (kids and parents) took far shorter showers because it was so cold. This also meant we had to clean the shower much less often. I would also be more awake and alert in the morning after a cold rinse.

  DOWNSIDES: I noticed I was getting more headaches and stiff necks, then I realised that the hot showers were helping me to de-tension and relax my shoulder and neck muscles which have become tight due to my long work hours writing code at a keyboard.

  Didn't notice any up or down occurrences of sickness in the rest of the family. Overall, I am glad we have hot water back now. At least I have a choice which way to go.

• by sytelus on 11/17/17, 3:41 AM

  TLDR; 3000 participants study that asked them to do cold showers for 30-90 seconds each day for 1 month. Main difference shown was ~30% reduction in sick days they took.

  On a side note, has anyone here tried wim hof method?

• by itchyouch on 11/17/17, 2:19 AM

  Dr. Rhonda Patrick goes over cold therapy (along with hot therapy) numerous times in her nutrition/health/biology/epidemiological research.

  cryo usually is -180 degrees F for 2 minutes. But a similar effect can be achieved with ~40 F (IIRC) exposure for ~4-6 hours. I think she has mentioned similar effects for immersion in cold water for several minutes as well.

  The benefits of cold shock are basically:

  * increase norepinephrine up to 5 fold which provides a ton of focus/attention. * induces biogenesis of mitochondria, thus increases endurance. * that biogensis turns white fat brown as fat cells grow mitochondria to generate heat to stay warm

  Looks like she has a report on it here: https://www.foundmyfitness.com/?sendme=cold-stress

  You can also listen to it in bits and pieces in various videos she has posted: https://www.youtube.com/watch?v=if-J8w2ay94

• by zzxxkk123 on 11/17/17, 1:54 AM

  I used to do this every morning... just take a normal hot shower, then at the end crank it full cold and endure until normalized.

  It's a free high, great way to start a day. I presumed endorphins are being released.

  Now I prefer to run a bunch of miles and immediately jump into the (cold) ocean while still all hot and amped up from the run. The water doesn't even seem cold, it's great. Normally people wear wet-suits in the ocean here.

• by conception on 11/17/17, 12:52 AM

  But not a reduction in how many days people felt ill. I wonder if this speaks more to self-help style "leaders take a cold shower in the morning to get their day started" jump-start to your day than to any health consequences.

• by twobyfour on 11/17/17, 10:55 AM

  This is not for everyone. I can do this and enjoy it in summer but not winter. I have poor circulation and am always cold as it is. In winter, the water comes out of our pipes at whatever ground temperature is - typically just a couple degrees above freezing.

  Tried it once for a week, and was stepping out of the shower nearly hypothermic and shivering violently. Immediately came down with a massive head and chest cold that required my first course of antibiotics in nearly a decade, followed by a tension related muscle injury that's still plaguing me three years later.

  Never again.

• by portlander12345 on 11/17/17, 4:04 AM

  Can someone tell me if their study design compensates for bias introduced by not everyone completing the study? It looks like only about 70% completed it.

• by JumpCrisscross on 11/17/17, 2:55 AM

  “The total amount of days a participant felt ill (including symptoms of cold and flu)” responded but “the total number of days of absence from their work due to sickness“ which the study’s designers view as “the most objective indirect parameter indicative of illness severity” did not.

• by chewz on 11/17/17, 5:02 AM

  I loved cold showers since beeing teenager. Always liked cold. Not used hot water sometimes for weeks in winter. In December me and friends regularly swim in Baltic Sea when it’s 0C outside (hot sauna and generous servings of vodka surely help).

  But I have read that hot shower in morning significantly lowers cortisol levels so I start the day with hot shower now, when available.

  Also since a few years I am living in SE Asia and hot showers taken few times a day open pores in skin and allow it breath better in this climate.

• by all_blue_chucks on 11/17/17, 4:15 AM

  People who take cold showers are just as sick, but call off work less? Maybe it's because the misery from the cold water masks the misery from the illness?

• by arkaic on 11/17/17, 4:07 AM

  I can offer my anecdotal experience. Been shutting off the hot water at the end of my morning showers and enduring the cold for a few minutes for the past 3 years. I have noticed that I get fewer colds. And with the colds I do get, their symptoms are lighter, and they go away much quicker, often gone in a day or two. And I haven't caught anything real bad, like a flu, since.

• by Fifer82 on 11/17/17, 12:36 PM

  Does anyone know why I prefer being cold more than others?

  I sleep with all the windows open and my other half has pyjamas, a double duvet and a hot water bottle. Like in December in Scotland.

  I also dislike wearing Jackets or Coats under any circumstances. I dislike hot drinks maybe apart from Soup.

  When people go on Holiday and basque in the sun saying it is perfect weather. My actual perfect weather (I believe I feel like they do when it happens) is for a low crisp negative temperature with no wind.

  For a long time I have wondered why I prefer this side of the fence and wonder if I have some weird lineage from the North.

• by flor1s on 11/17/17, 3:10 AM

  I feel like the benefits you obtain through cold showers disappear after a while as you get used to them. That's similar to the benefits I felt of meditation.

• by bksenior on 11/17/17, 2:35 AM

  I skimmed the cover page. If you shower at night are the advantages tracked to be local to only that moment or does it have a prolonged general benefit?

• by spodek on 11/17/17, 4:17 AM

  Joel Runyon's Cold Shower Therapy is an awesome introduction, at least for certain types, which includes me.

  https://impossiblehq.com/cold-shower-therapy

  I've taken cold showers regularly for years. One of the best things I've done for myself -- creating discipline, self awareness, etc. at zero cost in money or time.

• by simplyluke on 11/17/17, 3:35 AM

  Cold/heat exposure are great, cold water immersion in particular. I've observed positive effects on my physical recovery.

  But I have not seen a comment here warning that cold water immersion is absolutely not something you should try for the first several times alone, even in very shallow water (IE a bathtub). The risk of entering shock/going unconscious and drowning is non-trivial.

• by kromem on 11/17/17, 9:37 AM

  Because of the study design, there's no control group that would account for placebo.

  The placebo effect in several meta-analyses (Beecher, Haas) showed an effect in studies of around 30%.

  Coincidentally, people participating in this study felt less sick when talking a hot-cold shower by ~30%.

  Without being able to discount placebo, I am highly suspect of the results of this study.

• by codezero on 11/17/17, 6:56 AM

  In general I am very concerned about what is considered cold. Is this just unheated?

  Depending on the time of year the relative temperature of unheated has a broad range where I live. I’d be a lot more comfortable if this set a tight bound on the water temp. If it did and I missed it sorry.

• by DoubleGlazing on 11/17/17, 11:08 AM

  I had to cold shower for a January fortnight when we had issues with our gas boiler.

  One thing I noticed was that it got me alert much sooner in the morning. Typically I would get up at 7:00am, shower, eat and then head off to work to start at 9:00am, but my brain wouldn't really be in gear till about 9:30am.

  With cold showering the brain was in gear far sooner. I felt more willing to get out and get stuff done. Maybe that earlier alertness helps cancel out a desire to pull a sickie?

  That being said, the extra alertness wasn't worth the sheer torture of a cold shower.

• by markinthesea on 11/17/17, 12:26 PM

  It's interesting they only focus on the cold shower. I would have thought it would be short and barely give you enough time to get over the initial shock(cold shock response) - around a minute or so when the gag reflex hits and what would potentially drown you in open water. After that shock, things change.

  My personal experience is with swimming in the sea year round for 3 to 4 years. 2 to 3 times a week every week. I started in August to help acclimatise to the change in the temperature as it cooled. Temperature ranges from 18C in August to 4C in early March, give or take.

  The effects were great over all and I thought I was healthier for it. I understand the tightening of the muscle which some of the others mentioned as an experience. I got used to this and it seemed to relax me. I never really got the tight muscles thing except afterwards when I kind of wanted to tighten up.

  I would walk in at a reasonable pace. As others have said, with a meditative feeling. Once fully emerged and the shock had passed I could swim for a maximum of around 5 to 10 minutes at the coldest part of the year. Sometimes it was more a splash around for as long as I could stand it. I generally stopped and got out when my wrists started to cramp. I'm guessing the cold water would send the blood circulation internally away from the skin.

  It always felt the warmest in late September early October for some reason. The coldest place I ever swam was between two San Juan islands in August!

  Once out of the water I would feel warm and have a feeling of glowing. Drying off would be a pleasure despite the outside temperature. My overall demeanour would be very positive and up lifting. I've heard talk of endorphins or something along those lines being released in to the body.

  I never jumped in to a hot shower right after preferring to warm naturally and slowly. I felt warm for a good twenty minutes after getting out and being dressed fully whoever cold it was.

  The whole experience became slightly addictive which is why I did it so long. Work has now gotten in the way of that.

  There is a serious safety aspect to all this and it should be done with caution and understanding. This guy, Mario Vittone, was very informative on what's going on when trying to stay alive in cold water: http://mariovittone.com/2010/10/1-10-1/

• by hellofunk on 11/17/17, 7:00 AM

  > Twenty serious adverse events were reported, that were all considered unrelated to the intervention.

  Including one death.

• by starchild_3001 on 11/18/17, 6:32 AM

  I took cold showers for a month. Really liked the effects! I ended up wearing shorts and tshirt year round (in northern california), whereas the old me would be wearing several layers of clothing > 6 months of the year. I was taking cold showers daily for 5 months.

• by gadders on 11/17/17, 2:59 PM

  I tell you what has an even bigger effect on the number of sick days you take - going self-employed.

  I've taken one day off sick in the 8 years I've been an IT contractor, and that was because I set fire to my legs (in too much pain after a dressing change to WFH).

• by vleroybrown on 11/17/17, 12:35 PM

  For the past 2 months my family and I have been forced to take cold showers in Puerto Rico. I personally stoped showering for almost a month. I got so sticky it was unbearable so I finally showered again. The cold water was difficult to relax in.

• by shadykiller on 11/17/17, 4:25 AM

  I take cold shower just for the wakefulness. Always beats the morning coffee for me.

• by mythrwy on 11/17/17, 9:32 AM

  Showering in cold water also might keep the skin pores closed causing less absorption of whatever may be in the municipal water (fluoride, traces of pesticides, hormones from birth control etc).

• by NHQ on 11/17/17, 5:11 AM

  Cold showering isn't a health regimen; it's a beauty secret.

• by dangjc on 11/17/17, 3:43 AM

  I did this for a while. It’s good for increasing your brown fat.

• by BLanen on 11/17/17, 9:37 AM

  The problem with researching this is that the patient can't be blind to what treatment they're getting.

• by neilwilson on 11/17/17, 12:28 PM

  So essentially a cold shower wakes you up.

  Who knew.