#132 – AMA #16: Exploring hot and cold therapy

"All of the work that went into this analysis earlier in the year, it really changed my tune. And I think I'm now at the point where I kind of want to have a sauna, frankly, in the tool kit for longevity." — Peter Attia

Read Time 18 minutes

In this “Ask Me Anything” (AMA) episode, Peter and Bob explore the quality of evidence for hot and cold therapy. In the discussion, they evaluate the safety, efficacy, and opportunity costs of various hot and cold therapy protocols, and Peter ultimately considers the addition of dry sauna to his longevity toolkit. Once again, Bob Kaplan, Peter’s head of research, will be asking the questions. If you’re not a subscriber and listening on a podcast player, you’ll only be able to hear a preview of the AMA.

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We discuss:

  • How stress can show up as physical pain, and tips for changing time zones [1:45];
  • Literature overview of heat and cold therapy [7:15];
  • Cold therapy for delayed onset muscle soreness (DOMS) [12:00];
  • Quality of evidence for cold therapy for depression or immune enhancement [19:30];
  • Cold therapy and brown adipose tissue (BAT) [21:15];
  • Weighing the safety, efficacy, and opportunity cost of cold therapy [28:45];
  • An overview of heat therapy benefits [40:00];
  • Longevity benefits of sauna—reviewing the studies [41:30];
  • Limitations in the sauna literature—Where might we be fooled? [54:30];
  • Possible mechanisms conferring the longevity benefits of sauna, and how it compares to exercise [1:02:15];
  • Parting thoughts on sauna, opportunity costs, and Bob’s personal regimen [1:06:30]; and
  • More.


How stress can show up as physical pain, and tips for changing time zones [1:45]

Peter’s recent move to Texas

  • Peter recently finished moving his family from California to Texas
  • All things considered, it went well, but he did experience some added stress
  • In fact, his therapist told him, “Just to set your expectations, a move of this nature is among the three most stressful events to your marriage. . .on par with divorce and death.”

How stress can show up as physical pain

  • In the weeks leading up to the move, Peter was experiencing some physical pain in his body
  • Amazingly, the pain dissipated once the move was complete
  • He calls it an “aha moment”
  • Mechanistically, it’s hard to explain “why higher levels of cortisol. . .would actually lead to physical pain in my body. But there’s no question about it.”

Tips for adjusting to a new time zone

  • Prior to making the move, Peter’s family slowly adjusted their bedtime and wake schedule over the course of 10 days
  • By the time they made the move, their internal clocks had already adjusted

Jet lag protocol


  • Say you are going to London where it’s 5 hours ahead
  • On the day of departure, the idea would be to wake up super early to match London time (e.g., 3am)
  • That will allow you to be sleepy at a normal time once in London

⇒ See AMA #4 for the complete jet lag protocol


Literature overview of heat and cold therapy [7:15]

Peter and team’s research project:

  • Peter’s research team has put extensive effort into understanding the current literature on heat and cold therapy
  • The idea was to see if there was any reliable evidence that showed either heat or cold therapy to impact lifespan or healthspan
  • Often, heat and cold therapy studies are lumped together when they are really separate topics

An example of “lumping” is clearly seen in a large editorial paper that claimed heat and cold could positively impact in several ways:

1-A wide range of physiological responses including:

  • resistance to cardiovascular disease and mortality
  • endothelial function and arterial stiffness
  • walking ability and lower limb perfusion; shear pattern, blood pressure and circulating endothelin‐1 concentrations 
  • glucose metabolism 
  • autonomic nervous activity
  • cerebral protection
  • stress resistance

*NOTE: all the references cited for these benefit listed above were related to HEAT therapy

2-Another claim was an improvement of mental health (the only place where they cited a paper looking at cold therapy)

  • The supporting evidence for those were lackluster to say the least
  • And the only cold paper referenced was an n=1 using cold water swimming which had confounding variables


Cold therapy for delayed onset muscle soreness (DOMS) [12:00]

Cold therapy for DOMS (delayed onset muscle soreness)

{end of show notes preview}

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  1. Do the results of the dry sauna literature transfer to infrared saunas? What is the best way to think about this?

    • Peter mentioned that infrared does not provide the same level of benefit. With that said, it’s better than not dry sauna-ing.

  2. I have been a sauna enthusiast since being informed by Rhonda Patricks excellent writings and her very detailed podcast with Laukkanen. I rejoined my old club to access their excellent sauna and steam rooms. The benefits, both mental and physical are undeniable, especially when immediate post exercise, which is believed to enhance the training effect and release of HGH.
    Temperature is important for both efficacy and safety. The Finnish studies emphasis that the (presumed) benefits occur when the average temp is 80-100c at the level of the head. It’s important to understand that there’s a temperature gradient in the typical sauna. Typically in my sauna, its 93c near the ceiling and 53c at floor level. So, where you sit (or stand ) matters. Novice sauna users should gradually increase their exposure by sitting low for a short period, and building a tolerance … like starting out on a treadmill for the first time. Although a cool plunge is somewhat traditional, its not necessary for benefits and may be dangerous. Precipitous hypertension and bradyarrhythmia may occur, and fatalities though rare are documented. Gradual emersion is safer. Although sauna use is safe with underlying cardiac issues such as hypertension, CAD, and cardiac failure, prolonged exposure combined with cardiac medications can precipitate orthostatic/postural hypotension, and result in dangerous syncope. The commonest type of injury reported in Finland is thermal, secondary to alcohol associated falls onto hot rocks. The interaction of alcohol with medications may also be problematic.
    The average body temp rise is about 1C per 30 minutes, and this triggers the sweating, cardiovascular changes, metabolic changes such as HSP’s and activates the immune system. Temps of 38-39C increase clearance of bacteria and virus’s from the body, and fever is a primitive body defence mechanism against infection. Elevation of body temperature is now being investigated to treat sepsis. Suppressing temp during viral infection may exacerbate the illness. But, sauna use is not recommended while acutely ill.
    All forms of viral illness are reduced by heat therapy (sauna and steam etc), and the chances of getting infected are low. including COVID-19. Yet, “health authorities” reflexly shut down sauna and steam rooms ??
    30% of Finnish homes have sauna’s, and are very common in health spa’s and gyms, hence the widespread use. Anyone who doesn’t have 30minutes a day to devote to exercise and heat therapy is deprived or needs to “de-TV”.
    Heat therapy from hot baths may have similar benefits if the body temp rise matches sauna and is maintained for 20-30minutes …. and it may help sleep.
    Heat therapy is now becoming vogue for sports injury and recovery rather than the ubiquitous “ice pack”. Much more can be said, but enough for now.
    Cheers, Gary Bennett Branch (retired 74y old anaesthesiologist).
    PS how about Peter interviewing Fred Bartlit, an 87yr old superman.

    • Absolutely. Fundamentally it’s all about eliciting a (safe) rise in body temperature. Although steam rooms typically operate at a lower temperature than dry sauna (around 60C), because steam has x25 more heat energy than dry air, the body heats up quicker in a steam room than dry air. A gust of hot dry air is not dangerous, a gust of steam can cause serious burns. Steam also has beneficial effects on upper airway mucosa that is thought to enhance local immunity, and enhance viral clearance. Some prefer stream, some sauna. The Finnish studies clearly show, the dose matters – more is better. I follow 30min of sauna with a brief cool down, and then 15 min of steam …. love it.

  3. A question: if antioxidants impair some of exercise, does that include coffee, which is the largest source of antioxidants in most peoples diet ?
    Many advocates of fasting, for instance, laud the benefits of coffee as part of their regime, and Prof Guido Kroemer, a renowned researcher (see 2017 interview with Rhonda Patrick) group has shown that coffee enhances “autophagy”, and hence wont reduce fasting benefits (yes, he loves coffee).
    I exercise at the end of my 16hr fast, but do imbibe black coffee during.
    I break fast post exercise with coffee …. am I limiting muscle gains ?

  4. While I understand the “lack of evidence” and opportunity cost of cold water plunges I look at it from the perspective of fun and socialising with like minded people. Yet, I would like to minimise the risks related to it.

    What is your view of the quality of evidence in the studies below in relation to cardiac events and cardiovascular disease progression related to cold weather or cold exposure?


  5. Going one step farther than a steam room – is there evidence that a hot tub could have similar benefits? No way to add steam at my present house, but a hot tub or barrel sauna would be possible.

  6. Would exercise in cold temperatures, similar to Peter’s open water swimming be a way to get both the benefits of exercise and cold therapy? So that way it isn’t a trade-off of time? For example, in the winter, if it is very cold out (say below 0 Celsius) , would running in just shorts and shoes for 45 minutes be better than just running but wearing cold weather gear? Or is the risk of afterdrop too great? I can’t find any research that has exercise at the same time as cold therapy.

  7. Peter,
    Great read, as always.

    I’m interested in the notion that “The greatest benefits to reducing DOMS occurred when treated 24 to 72 hours post exercise”. I have looked through the papers (except the last one, which I could not access) and have not been able to find any support for this. What I have found is that the greatest benefits seem to appear in the 24 to 72 hour post exercise follow-ups. The cold-water immersion therapy however seems to have happened in the direct aftermath of the exercise sessions. Is this just sloppy reading on my part or has the follow-up time been mixed-up with the cold water-immersion time in the article?

    As of now, the argument for not doing cold therapy directly after an exercise session seems solid enough for me to hold off an hour or two with the cold showers.

  8. I wish there was a discussion of Wim Hof and his method here. He advocates cold therapy and deep breathing. His book cites many studies of physiological benefit.
    I have been doing the breathing daily and start my shower in the cold. I could not get to the studies he cites to determine their value. I do feel refreshed after breathing and the cold of the shower. I don’t know if there is any scientific evaluation of their merit. Unfortunately, to hear Wim talk, he sounds like a nut.

  9. While it is a bit dated, this researcher (Charles raison) gives his evidence that supports Attia’s notion that heat saunas mimic exersize:

    see at ~ 46:00 where researcher breaks down that experiments show that saunas  (or any high heating) induce muscles to produce massive IL-6 inflammatory but not IL-1 or TNF, so it instead triggers the body to respond with massive anti-inflammatory chemicals/processes. They find this is the same as what muscles do in heavy exercise so sauna seems to mimic that.  To evidence that further when they suppressed IL-6 all benefits of muscle exercise went away.  So, this all leads them to believe that saunas mimic heavy exercise, including some of the anti-diabetes benefits.

    Also, I would suggest that before doing heat saunas (or any sweating) I think it is smart to eat lots of brocolli sprouts b/c of this finding:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4125483/ Rapid and Sustainable Detoxication of Airborne Pollutants by Broccoli Sprout Beverage: Results of a Randomized Clinical Trial in China

    Broccoli sprouts are a convenient and rich source of the glucosinolate, glucoraphanin, which can generate the chemopreventive agent, sulforaphane, an inducer of glutathione S-transferases (GSTs) and other cytoprotective enzymes. A broccoli sprout-derived beverage providing daily doses of 600 μmol glucoraphanin and 40 μmol sulforaphane was evaluated for magnitude and duration of pharmacodynamic action in a 12-week randomized clinical trial. Two hundred and ninety-one study participants were recruited from the rural He-He Township, Qidong, in the Yangtze River delta region of China, an area characterized by exposures to substantial levels of airborne pollutants. Exposure to air pollution has been associated with lung cancer and cardiopulmonary diseases. Urinary excretion of the mercapturic acids of the pollutants, benzene, acrolein, and crotonaldehyde, were measured before and during the intervention using liquid chromatography tandem mass spectrometry. Rapid and sustained, statistically significant (p ≤ 0.01) increases in the levels of excretion of the glutathione-derived conjugates of benzene (61%), acrolein (23%), but not crotonaldehyde were found in those receiving broccoli sprout beverage compared with placebo. Excretion of the benzene-derived mercapturic acid was higher in participants who were GSTT1-positive compared to the null genotype, irrespective of study arm assignment. Measures of sulforaphane metabolites in urine indicated that bioavailability did not decline over the 12-week daily dosing period. Thus, intervention with broccoli sprouts enhances the detoxication of some airborne pollutants and may provide a frugal means to attenuate their associated long-term health risks.

  10. While there’s a lot more epidemiology (almost all of it from Finland) on dry sauna, there are a number of clinical trials of Waon therapy (a form of infrared “sauna”), particularly for heart failure:

    Not much use in intermittent claudication, however:

    On the question of the overlapping effects of exercise and the question of opportunity costs:

    And this study finds following exercise up with sauna seems to impair functional gains, similar to cryotherapy:

  11. Im curious why no one has mentioned mitochondrial function? There are endless claims that cold plunge therapy increases the function and biogenesis of mitochondria. Is there any good science behind this? It seems to me that this is the most important claim for cold therapy. I expected this topic to be front and center in the discussion. Any thoughts?

  12. Pretty disappointed to not see any discussion of norepinephrine and vasoconstriction when talking about the benefits of cold exposure. As well as things like contrast hot/cold showers or what benefit if any from going from a sauna to a cold shower/tub as many people do.

    I’d also add that for me there is a psychological benefit of forcing myself to do something uncomfortable like turning the shower knob from piping hot to ice cold.

  13. Dr. Attia,
    I watched a movie, “My Octopus Teacher” on Netflix. The film maker had been stricken with depression. He lived on the South African Coast which appeared similar to the California’s central coast complete with kelp forests, otters, and octopus. The film maker snorkeled in the cold water without a wet suit as he documented his contact with an octopus for a year. As time went on, the film maker began to share his excursions with his son suggesting that his mood was improving. Given your experience in stress/resilience and ultra marathon ocean swimming, I thought this film might interest you and possibly your family.

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