Updated: Jan 29
Do you know what healed me? The cold water. It brought me back into reality. Instead of being guided by my broken emotions toward stress and sorrow, the cold water led me to stillness. - Wim Hof in 'Why the Cold is a Noble Force.'
Diagnosed with depression and anxiety when she was 15, Brooke Lily discovered that cold water swimming helps her manage her negative emotions. In the video above, she describes the ecstatic rush she experiences in response to the cold water.
A study of hormone concentrations in the blood resulting from cold water immersion supports her description. For example, plasma concentrations of noradrenaline and dopamine were increased by 530% and 250% (respectively) in young men immersed in 14C water (Šrámek et al. 2000). Given the role that noradrenaline plays in calming the fight or flight response to stress (van Stegeren et al. 2005) and the correlation between dysregulation of the dopamine system and the inability to feel pleasure (Belujon & Grave 2017), any remedy that provides such a boost to these two "happiness hormones," is going to lift mood.
Can cold water be therapy for depression?
It did in the case of a 24 year old woman named Sarah with major depressive disorder that failed to respond to traditional pharmaceutical interventions. After three months of cold water swimming, depression was resolved and she was able to discontinue all her medications (van Tulleken et al. 2018). Her journey to mental health became the subject of a 2016 BBC documentary series called 'The Doctor Who Gave Up Drugs.'
After even a brief swim, I feel elated for hours and calm for days. - Sarah, in The Doctor Who Gave Up Drugs
Cold Shock Creates An Anxiety Response
These remarkable results are counter-intuitive, given the pain and anxiety associated with deliberate cold exposure. According to Professor Michael Tipton, who supervised Sarah's experiments in cold water swimming, the first thing that happens when entering the cold water is something called, "the cold shock response" (Barwood et al. 2017). Particularly when immersion is accidental, activation of cold thermal receptors on the skin initiates a classic fight or flight stress response that is characterized by:
increased breath rate (the gasp reflex),
a release of glycogen from the liver into the blood stream, and
shortly afterwards, massive increases in catecholamine neurotransmitters, such as dopamine, and norepinephrine.
Tipton has built a cold water laboratory in the United Kingdom to study the cold shock response in his research subjects.
Cold Therapy More Effective Than Anti-Depressants?
Like others before him (e.g., Huttunen et al. 2004, Mäkinen et al. 2008, Shevchuk 2008) Tipton discovered that practicing structured breathing and relaxation while immersed in cold water can strengthen the parasympathetic nervous system and create a feeling of euphoria when the plunger emerges from the cold water. For example, one study measured significant improvements in mood among an experimental group of 34 depressed participants after just three weeks of whole body cryotherapy (Rymaszewska et al. 2008). A decade later, the same researchers found similar results with 21 patients who experienced significant relief from their depression after just two weeks of whole body cryotherapy (Rymaszewska et al. 2018).
Physiology of Deliberate Cold Exposure
Although part of the benefit of swimming outdoors must be coming from the comradery, sunshine, and immersion in the natural world (e.g., Oliver 2021), the mood-lifting experience of cold water swimming is not just about being outdoors, or with friends. According to Professor Andrew D. Huberman, the practice of cold exposure for improving stress management can take place in a cold shower or an ice bath, too.
Huberman's description of practices that raise stress thresholds correspond well with the Wim Hof Method of breathwork, followed by deliberate cold exposure. However, maintaining full consciousness is critical for safe practice of whole body cold water immersion, whether in open water or in an ice bath, which is why Huberman cautions:
Never practice hyperventilation while immersed in water.
While the noradrenaline/dopamine rush a mood booster, among the most intriguing research advances is what we call the oxytocin hypothesis put forward by Talash et al. (2021). While the essential role of oxytocin in psychiatric, metabolic, and immune system disorders is already well described, these authors may have discovered a role for cold exposure in modulation of oxytocin levels.
Better known as "the love hormone," (Colaianni et al. 2015) oxytocin plays a critical role in control of blood sugars, maintaining bone density and a youthful body composition. Moreover, oxytocin deficiency is associated with low mood (Scantamburlo et al. 2007). Therefore, ensuring adequate oxytocin levels is critical to maintenance of good physiological and psychological health.
Talash et al. (2021) are the first to hypothesize that cold exposure upregulates production of oxytocin in the hypothalamus in ways that might be critical to signaling thermogenesis and adaptation to the cold by recruiting new brown fat cells. If this is the case, then cold plunging in groups or with a partner may help build powerful relationship bonds.
Knetchtle et al. (2020) describe the experiences of some of the early pioneers of cold water swimming, including world record holder Lewis Pugh. The success of celebrities like Pugh, Wim Hof, Joe Rogan, and Ben Greenfield has popularized the practice of cold water swimming such that now healthcare workers in the UK National Health Service are using cold water swimming to help them manage stress. One study surveyed over 700 winter swimmers in the United Kingdom and discovered "outdoor swimming was associated with perceived reductions in symptoms of poor mental health" (Massey et al. 2022).
For those contemplating a winter swimming program of their own, Manolis et al (2019) provide an extensive review of the benefits and risks, and tabulate some training tips that may help novices acclimate. These include:
proceed gradually from warmer to colder temperatures, and shorter to longer exposure times, over a period of weeks,
go feet first (not head first) into the cold water,
follow a regular schedule -- e.g., at least twice a week,
having rewarming resources available, such as a warm car or a hot drink,
exercise following cold exposure,
avoid swimming while under the influence of alcohol.
Nonetheless, you don't have to wait for winter, or a trip to the beach to get the benefits of cold water therapy. One of our customers reports that they were able to discontinue six years of prescription anti-depressants after starting a daily ice bath practice. Another reports that he calls his Morozko ice bath "the mood changer."
You don't even have to own an ice bath.
Actress AnnaLynne McCord, who recently revealed that she has been diagnosed (by brain specialist Dr. Daniel Amen) with dissociative identity disorder, has described on Instagram how her ice bath practice help her manage anxiety.
Her experiences corroborates the science on dopamine production, given that she self describes that 15 minutes at 42F makes her feel "HIGH AF 😂😂😂".
UPDATE 29 Jan 2023
A new study from the United Kingdom examined the mechanisms in the brain that contribute to the improvement in mood resulting from deliberate cold exposure. Rather than just measuring dopamine, which we already know is associated with pleasure, the research team sought to investigate ways in which the brain might function better because of cold water immersion.
They recruited 39 healthy participants that had not been practicing deliberate cold exposure for at least a year and administered two different types of diagnostics pre- and post-cold water immersion:
The Positive and Negative Affect Schedule (PANAS) is a questionnaire that measures emotional state, and
Functional MRI describes activity in the brain.
Participants then submerged up to the neck for 5 minutes in a cool (68F) water bath.
For regular ice bath practitioners I doubt that 68F (20C) would activate anything. In fact, temperatures that high feel warm to me now. But these participants had no experience with any type of cold water exposure, and that may have been sufficient to cause a gasp reflex or shivering in them. In any case, the researchers seemed to take the experience very seriously, reporting that they monitored their subjects closely and even stopped one bath before the five minutes had completed because they observed six irregular heartbeats. So we might surmise that these participants felt challenged by their cold plunge experience.
The study participants experienced several measurable effects. For example, their heart rates and breathing volumes increased. More importantly, particpants reported "feeling more feeling more active, alert, attentive, inspired, proud, and less nervous after cold-water
immersion" (Yankouskaya et al. 2023). The positive attributes on their PANAS scores went way up, and negative way down.
Just five minutes of whole-body cold water immersion improved mood in a recent United Kingdom study of 39 healthy participants.
The fMRI scan data may reveal some clues about how. After cold exposure, researchers observed measurable increases in the functional connectivity between regions of the brain associated with positive mood. In particular, cold water immersion seems to strengthen regions of the brain that are engaged in regulation of emotions. They conclude "our findings suggest that short-term head-out immersion in cold water is associated with a facilitated positive affect and reduced negative affect" (Massey et al 2023).
This new study strengthens my view that deliberate cold exposure is positive for brain health, and that in addition to the improvements in neurotransmitters and hormones, there are also positive physiological changes in the brain associated with the ice bath.
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For personal stories about journeying through the cold, listen to The Morozko Method podcast https://anchor.fm/adrienne68.