Updated: May 9, 2022
The principal benefit of the icebath is psychological.
The science of cold exposure can be organized into three categories:
1. exercise recovery,
2. immune system and endocrine benefits, and
3. improved psychological response to stress.
Most of the research and popular media is about exercise recovery. Also, there's some new research in immune system benefits and other hormonal responses to cold exposure that suggests the recruitment of brown fat, white blood cells, and release of neurotransmitters like norepinephrine can have therapeutic effects. For example, this recent study finds that cold exposure relieves symptoms of fatigue in patients with multiple sclerosis, although the mechanisms are not yet understood.
Still, Wim Hof instructors like Beat Brun often say that the psychological benefits are the most important, and that's where the least research has been done. What little exists is focused on something called the Socially Evaluated Cold Pressor Test (SECPT).
The SECPT is a standardized protocol for inducing stress in subjects for the purpose of evaluating their response. It requires submerging the subjects' right hand in freezing cold water for 3 minutes, while under observation. (It turns out the observation has been shown to increase stress levels). Researchers then measure heart rate, cortisol levels, and other markers of physiological response to cold exposure stress, and ten years of collecting data has shown that the SECPT is effective for creating "autonomic arousal" -- i.e., the fight or flight response.
For those of you that are practiced cold plungers, you're probably amused (as we are) by the relative insignificance of submerging just one hand, for just three minutes, when we've been practicing daily whole body cold exposure. But the SECPT wasn't developed for practiced plungers like us, and that's the point.
When subjects practice with the SECPT, researchers often find that they gain control of the autonomic anxiety response, exactly as Wim Hof claims.
The question that hasn't been answered yet is whether regular practice of whole body cold exposure in an ice bath strengthens the parasympathetic nervous system to the extent that it can make us more calm, relaxed, and creative in other stressful conditions.
Beat Brun believes it can.
To test his claims, a Swiss reporter decided to try Beat's workshop for herself. She and Beat created a video of her experience, and we've taken the trouble to translate it from German to English.
My Stress Reactions
[Anna, speaking]: "Let's face it, I'm stressed. You're stressed. We all are stressed. Today I am learning how to deal with stress, in ice cold water."
[Anna, narrating]: (I am) going to a workshop in my jogging pants. This is the dresscode here.
[Anna, speaking]: I think we are good. This is Beat, our instructor.
[Beat]: "We breath deep into our belly, 30 times."
[Anna, narrating]: And this is us. We pump ourselves with air. With these techniques, we activate our bodies. I will have nasty muscle soreness tomorrow.
We visualize how we will go into the water. This does not make me less skeptical.
[Anna, speaking]: "I am very much sensitive to cold, so I do not think now that ultimately I can hack it in the cold water. We will see!"
[Anna, narrating]: Beat explained to me that we all have stress reactions: shortness of breath, loss of concentration, panic. These do not matter.
[Beat]: "By consciously breathing deep and slow, we condition ourselves to have a new stress reaction. And you can apply this adaptation in your everyday life.
"When you are with your Boss, or in another stressful situation, you can do what you have practiced in the icewater, so that you don't breathe improperly or make mental mistakes. You stay present, and you can focus on your breath to control your stress."
[Anna, narrating]: That's what we are trying to do in Lake Obersee today -- a relaxing place when the water is not 46F degrees.
[Anna, narrating]: My stress reaction says "You could just lay on the couch!" but my motivation has a love-hate relationship with stress.
[Beat]: Relax yourself. Exactly! With your exhale, you reassure us.
[Anna, narrating]: After two minutes, the pain subsided, and the good hormones kicked in.\
[Anna, speaking]: "OK, now I
must laugh!"
[Anna, narrating]: Beat says bio-optimization is a technology for consciously breaking our stress reaction.
[Anna, speaking]: I found the challenge of the water the most difficult. Because we talked so much about how we would feel pain, I felt more pressure when we jumped in the Lake. But I also never thought that I could have endured it so lang, and I feel like it was pretty cool.