Cold Showers and Contrast Showers for Immune Health, Brain Health, and Longevity

  • by Nils Osmar. Feb. 22, 2024
  • This post is not intended as, and should not be taken as, medical advice. 
  • See full Medical Disclaimer
  • Image by 3403909 from Pixabay

Two recent studies suggest a correlation between cold exposure, immune health, and longevity.

Study 1: The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial

From the study:


The aim of this study was to determine the cumulative effect of a routine (hot-to-) cold shower on sickness, quality of life and work productivity.


Between January and March 2015, 3018 participants between 18 and 65 years without severe comorbidity and no routine experience of cold showering were randomized (1:1:1:1) to a (hot-to-) cold shower for 30, 60, 90 seconds or a control group during 30 consecutive days followed by 60 days of showering cold at their own discretion for the intervention groups. The primary outcome was illness days and related sickness absence from work. Secondary outcomes were quality of life, work productivity, anxiety, thermal sensation and adverse reactions.


79% of participants in the interventions groups completed the 30 consecutive days protocol. A negative binomial regression model showed a 29% reduction in sickness absence for (hot-to-) cold shower regimen compared to the control group (incident rate ratio: 0.71, P = 0.003). For illness days there was no significant group effect. No related serious advents events were reported.


A routine (hot-to-) cold shower resulted in a statistical reduction of self-reported sickness absence but not illness days in adults without severe comorbidity.

Study 2: Cold temperature plays a central role in longevity

From an article interviewing the authors of the study:

Aging is a major risk factor for several neurodegenerative diseases associated with protein aggregation, including Alzheimer’s, Parkinson’s, Huntington’s and ALS. Vilchez added: “We believe that these results may be applied to other age-related neurodegenerative diseases as well as to other animal species.”

A key finding was that the proteasome activity can also be increased by genetic overexpression of the activator. That way, disease-causing proteins can be eliminated even at the normal body temperature of 37 degrees Celsius. These results may provide therapeutic targets for aging and aging-associated diseases.

My thoughts

  • The first study shows possible immune benefits from taking hot-to-cold contrast showers.
  • The second suggests possible longevity benefits and protection against neurodegenerative diseases.
  • Previous studies have suggested a connection between cold exposure and mitochondrial biogenesis, expressed as the browning of white fat.
  • While the existing studies are interesting, more are needed before concluding that taking cold showers or ice baths could increase the human lifespan.

What I’m doing

  • I’ve been taking cold showers and hot-to-cold showers off and on for the past four years. I recently resumed taking them, usually first thing in the morning.
  • While I can’t prove that the showers were the effective factor, speaking anecdotally, I can say that each time I’ve been found myself catching a cold or other bug, taking a hot-to-cold contrast shower has quickly knocked it out. I seem to “have a cold starting” before the shower and it’s gone after the shower. (I also follow some other protocols, so it may not only be the shower that’s helping)
  • I also like keeping my house cool, around 65 degrees F during the day and 60 degrees F at night. I have to remind myself to turn up the heat when friends visit.

My morning ritual

  • One easy routine (for me) consists of getting up in the morning and putting on some coffee, then taking a quick contrast shower while it brews.
  • During the shower, I turn the hot water as hot as it will go without being scalding for three minutes; then turn it to icy cold for two; then hot again for two; then end on two minutes of cold. (It’s important in my experience to end the shower on cold.)
  • After the shower I spend ten minutes in my red light booth (it’s red light from a cool lamp, not a heat lamp.)
  • I find the ritual brisk, bracing and energizing, and a nice way to start the day.

Not medical advice

This article is not intended as, and should not be taken as, medical advice. I’m not advising that people eat any particular diet or take any particular supplement(s), just reporting on what I’m doing. Supplements, like medications and other interventions, can have side effects; I would encourage people to research both possible benefits and side effects before starting on any supplementation regimen, and consult with a medical professional about any issues which might have a medical component.  See full Medical Disclaimer

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