The question: If you practice the Wim Hof Method’s breathing daily for just 15 days, does it produce measurable improvements in heart rate variability, blood pressure, or stress response?
The short answer: A controlled trial had healthy participants practice the Wim Hof Method daily for 15 days and measured resting HRV, blood pressure, arterial compliance, and response to a cold-pressor stress test before and after. The study found no significant improvements in any cardiovascular parameter, perceived stress, or affect. This was a short-term study in healthy people, so it speaks to a 15-day window specifically and doesn’t rule out effects from longer practice — but it does undercut claims of quick, dramatic cardiovascular change within two weeks.
What the study did
The study, published in Scientific Reports in 2023, compared two groups of healthy people who had never practiced the Wim Hof Method: a control group and a group that practiced it daily for 15 days. The practice group did the method's breathing protocol of cyclical over-breathing and breath holds, daily cold showers and a mindfulness practice. They learned it from the published protocol rather than from an instructor or Wim Hof himself, which the researchers did to reduce a guru effect. The 15-day length was chosen because, according to the paper, Hof says positive changes should appear within 10 days.
What it found
Before and after the 15 days, researchers measured heart rate variability by ECG, blood pressure by cuff, arterial compliance by pulse wave analysis, the cardiovascular response to a cold pressor test (hand in ice-cold water), and perceived stress and well-being. Compared with the control group, the Wim Hof group showed no significant change in heart rate variability, blood pressure or arterial compliance. Despite daily cold showers, their response to the cold pressor test did not change either. Jesse notes that participants reported modest subjective improvements in well-being and stress resilience, but the study found no significant improvement in perceived stress or affect.
What it doesn’t show
This was a short study in healthy people, so it speaks only to a 15-day window and does not rule out effects from months or years of practice. It does, however, test the claim that the method's benefits appear within about 10 days, and on that timeline the measured cardiovascular and stress outcomes did not move. It says nothing about breathwork in general.
Key points
- Fifteen days of daily Wim Hof Method practice produced no significant change in HRV, blood pressure or arterial compliance.
- Daily cold showers did not change participants' physiological response to a cold pressor test.
- The results undercut claims of quick cardiovascular change but do not address longer practice.
Common questions
Why did the study last only 15 days?
The researchers quote Wim Hof as saying positive changes should appear within 10 days. They set the study at 15 days, giving five extra days beyond that claim.
Did participants learn the method from an instructor?
No. They learned it from the published protocol, without an instructor or Wim Hof himself, which the researchers did to avoid a guru effect influencing the results.
Does this mean the Wim Hof Method has no effect?
Jesse says the study does not show that. It shows the method did not produce measurable cardiovascular or stress-response changes in 15 days, which suggests it does not act as quickly as is sometimes claimed.
What is a cold pressor test?
Participants place a hand in ice-cold water while researchers measure the cardiovascular response. It is a standard way to gauge how the body reacts to a physical stressor.
Study cited: The effectiveness of the Wim Hof Method on cardiac autonomic function, blood pressure, arterial compliance, and different psychological parameters. Scientific Reports, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC10579249/
Practice this: Best Breathwork for Beginners: 4/6 Ratio
Read the full transcript
Auto-generated from the video captions, so expect small errors.
Welcome back to the Breath channel. My name is Jesse. This is the Breath Lab. This is our weekly program where we cover the most up-to-date science in the field of breath work so you can make better decisions, you can have a more grounded practice. Today's episode is covering a study that was published in 2023 and scientific reports over the effects of the Wimhof method on cardiovascular health. Now, this is a study that took two groups of people who had never practiced the Wimhof method before. One was for the control, the other they taught the Wimhof method. Now this is a protocol that is probably the
most famous protocol in all of breath work today. It involves cyclical oval breathing a long apnea or sometimes we call it a retention and we repeat this for multiple times. The protocol is so well known you can take a look at the books you can take a look all over the place you can find this protocol. Now having said that in addition to the breathing protocol there is a practice of cold training. In this particular study these people had never done cold training before. So they were starting with cold showers. So each day they were required to do cold showers and then they were also
required to do the mindfulness practice. So so the three pillars of the Wimhof method were included in this and they were taught this based off of the published protocol of the Wimhof method. This wasn't taught to them by an instructor or by Wimhof himself. And in the paper they talked about the the guru effect. They they wanted to uh uh to say well you know we don't want that to be a factor. So, this was primarily, hey, here is how to do this protocol. We want you to do this every single day. We're going to test you in multiple ways. And let me tell you,
they tested a lot of things in this study. The first thing they examined in the study was HRV, heart rate variability. Now, simply put, heart rate variability is a measurement of the flexibility of the autonomic nervous system. So, sometimes we would say it's a way of measuring veagal tone. What this ultimately would mean is that if the Wimhof method has a positive effect on stress resilience and on autonomic flexibility, we should see an increase in heart rate variability. The way that this was measured was by hooking everyone up to ECGs so that they can get a good measurement of heart rate variability before and after
the 15-day protocol. The second thing they covered was blood pressure. So if we see a positive impact on cardiovascular health, it's likely that that we will see a improvement in overall blood pressure. And to do this, they just use the standard cuff and they did this before and it is after the 15-day protocol. The next thing they covered was arterial compliance using a pulse wave analysis. This ultimately measures how flexible the arteries are. And the more flexible we tend to see those arteries, the healthier the cardiovascular system. So if the Wimhof method shows an increase in arterial compliance, what that means is it's having a
positive effect on the cardiovascular system. Number four was, and we're not even done yet, but number four was the cold press test. And this is quite literally where they put your hand into freezing cold water and they test your cardiovascular response to that stressor. So this is something that you can't really fake. It's something that whenever you put your hand in there, you're going to have an autonomic response. Is that a sympathetic response or are you able to stay calm in the face of that cold stressor? So, they tested that before and they tested that after. Last on the list, they tested perceived stress and
well-being. So, while the other measurements were objective measurements, these would be more of a subjective nature. So, how do I feel about myself? How do I feel about my ability to handle stress? So that is a long list of things that they are testing and all of them are related to our cardiovascular health and the flexibility in our autonomic nervous system. Are we becoming more resilient as a result of this protocol and can that be measured objectively? Now here come the results and they may be a little surprising. One, they check the HRV. All right, so we talked about this. This was done by ECG
and they tested before and after. There was no noticeable change between start and the end between the group that was practicing the Wimhof method protocol and the group that was in the control. The next thing they tested was blood pressure. They saw no major changes between the Wimhoth group and the group that was in their control. When it comes to arterial compliance, again, we didn't see any measurable changes, anything that was robust enough to say, "Yes, we're seeing a change based off of the protocol." This was again comparing people that were in the control versus people who are doing this protocol. on the cold presser
test. Now, this is the one that I really was surprised by, especially because part of the Wimhof method is cold training. And you would expect that if you're cold training every day, you're going to have a higher resilience at least somewhat against a cold stressor test. So they put their hand in the ice cold water in the beginning, they put their hand in the ice cold water at the end, and they saw no measurable changes between the physiological reactions that occurred as a result of the cold presser test. So we didn't see any major changes in that in that study. When it came to the
subjective measurements, participants did report a modest improvement in their overall well-being and stress resilience. And this just shows that you can feel better without having a physiological change that is underneath it. However, when we look at the breadth of this study and there are few studies that study so many different aspects of a specific protocol, it is clear that we don't see those physiological changes. Now, the first thing that you may ask and this was the first thing that came to mind for me. This was a 15-day study. This was not months. This was not years of practice. This was 15 days. And you may
be like myself and and I think it's it's just fair to ask the question, why did they just do 15 days? What what ex what kind of changes did they expect to see in those 15 days? Well, when asked about this, and I am going to just read a quote from the actual study. It says, "According to Hoth, positive changes of the Wimhof method should already manifest themselves within 10 days. Thus the participants were instructed to perform Wimhof method daily over the course of 15 days. So the 15 days wasn't arbitrary and the 15 days was according to the researchers in the notes they actually
were giving a 5day sort of bonus time compared to what according to them Hoff said should be the time that you should see the change. Now, this study, it tested a lot of things and it showed no noticeable results other than some mild changes, subjective changes in stress resilience and well-being in a matter of 15 days. Does that say that the Wimhof method has no effect uh or that it doesn't work? No, it does not. What it does say is that it doesn't act maybe as rapidly as sometimes is claimed. One of the benefits of looking at the science is that we can sort of
have a sober and honest look at things without the hype, without the excitement, without the background music that we often get, without the marketing that is often part of the media that we're often fed. And when we look at the science, we can say, okay, maybe this doesn't have such a fast result. Maybe it's something that takes longer. Okay, a lot of mitigations take longer. But when we look at the science of the claims that are made, and this was a claim that was it was supposed to be 10 days, we can often say sometimes there's a little too much hype. Sometimes there's a little
bit too much marketing involved. Science doesn't attack methods. It's not for or against a style or a technique. What it does is it calibrates methods. It calibrates the way we see things. It calibrates the way we interpret things. and it helps us have a sober and honest look at what's really happening at the mechanisms beyond the mythology. So, I hope you enjoyed this. This is one of those weird ones that just sort of dropped in our laps. We did not have this on the radar, but again, thanks so much for sending this to us uh to one of our viewers. Um we are open to
looking at other studies if you'd like to send those studies to us. Honestly, we have every single episode planned for the whole year and so we we didn't really expect to receive studies, but it's always nice to receive studies. And thank you for your questions and your comments. So, the study is below if you want to take a look at that. In our next episode, we're going to be examining a technique that is much more quiet, but possibly much more powerful. And we're going to be comparing two variations of that technique. One using balanced breathing, one using an extended exhale. And only one had the
most profound effects on the physiology. So it may be up here when you watch this, maybe it's not. If not, I'll see you next week for the breath