Ice Bath for Mental Health
- Thomas P Seager, PhD
- Mar 13
- 10 min read
Cold plunge therapy can correct mood disorders
Summary
The testimony of people who have used ice baths and winter swimming to resolve mental health disorders & major depression suggest that cold plunge therapy is a powerful tool for boosting mental health.
Three mechanisms are engaged during cold plunge therapy:
boosting brain metabolism,
releasing neurotransmitters and hormones that lift mood,
and strengthening the autonomic nervous system.
Sharing the experience of cold plunging with others can deepen connections, resulting in lifted spirits.
When traditional mental health therapies fail
As I wrote in Depression Cured by Cold Plunge, some people who fail to respond to traditional talk therapy and anti-depressant medications have nevertheless resolved their major depression with the benefit of whole-body cold-water immersion. To understand these experiences better, in the Summer of 2024, I convened a panel of subjects who have each experienced significant relief from mood disorders in as little as one session of cold plunge therapy:
One man confided that he had tried supplements, therapy, and everything he could think of... yet nothing was helping until he tried a Morozko ice bath. Cold plunge therapy became his stabilizer--like a rock that he can depend on, when nothing else was working.
In another instance, a man was diagnosed with anxiety, OCD, and Tourette's syndrome when he was nine years old. His entire life since has been a struggle with mental health disorders. He discovered that swimming in a 38-degree cold river brought him relief from his anxieties and that all of the difficult thoughts and emotions he had been carrying went away.
A third man described how his attempt at suicide by drowning was interrupted by the cold Baltic Sea. Once he plunged into the water, he found new sense of perspective, and he realized that he wanted to live.
How can these three men experience such a rapid reversal from their mental
health challenges after just one or two sessions in the cold water? I will explain these mechanisms that are initiated by whole body cold water immersion below.
The brain demands metabolic energy
Mitochondria are critical for mental health
It is important to know that the brain takes about 25% of all the energy used by the human body. That is, about a quarter of your caloric intake goes into just fueling your thoughts. When mitochondria in the brain are damaged or defective, or if there are disorders in the gut or metabolism, then it's likely that the brain isn't getting the energy that it needs. This means that it can't perform the difficult cognitive work that is often associated with other therapies, such as cognitive behavioral therapy (CBT) or dialectic behavioral therapy (DBT). In particular, these strategies require intensive cognitive reassessment or reframing of difficult emotions.
Cognitive therapies typically call upon a subject to question their feelings, or question their automatic responses, with prompts like:
Is this true?
Is there another way to think about it?
Can I find the dialectic, or the two truths that might seem in opposition to each other, but can be true at the same time?
While these techniques can be very powerful tools for managing catastrophizing, obsessive thoughts, or all-or-nothing thinking, they will not be effective without energy from the mitochondria required to fuel those thoughts.
Cold therapy stimulates mitobiogenesis
Explained in Ice Baths for Mitochondrial Therapy, cold therapy stimulates mitobiogenesis--i.e., creation of new mitochondria--that resolves metabolic disorders. Mitochondria convert blood glucose, lipids or ketones into ATP to power & provide energy for almost all processes in the body. This energy can be used to move muscles, repair tissues, or fuel growth.
In other words, every function in the body depends on mitochondria for life.
When mitochondria are rejuvenated through cold exposure, insulin sensitivity improves, energy improves, and overall health benefits. However, when mitochondria are defective, and insulin resistance is high, brain function suffers.
Brown fat is associated with brain health
Alzheimer's is a good example of what's sometimes called type three diabetes. It originates in metabolic dysfunction, and metabolic therapies can slow or reverse its progression, but brown fat is not just for metabolism. In Brown Fat & Brain Health, I review the mechanisms in which brown fat may help reduce risk of cognitive decline further in detail.
Other lifestyle factors, such as receiving sufficient levels of magnesium supplementation, also contribute to proper mitochondrial function. For example, Magnesium is Critical for Cold Thermogenesis explains how every metabolic function in the human body relies on magnesium, such as:
energy production,
protein synthesis,
testosterone production,
and Vitamin D.
That is, magnesium drives metabolism, making it essential for functions in the brain, liver, kidneys, and repair of DNA. Because of this, magnesium plays a critical role in the mitochondria — so much so that concentrations of magnesium are about ten times higher inside the mitochondria than elsewhere in the human cell. And nowhere in the body are mitochondria more densely packed than in brown fat.
Although it remains in constant communication with the thyroid and is essential to regulating your metabolism, brown fat is also a secretory organ. It will produce neuroprotective factors like FGF21 and brain-derived neuroprotective factor (BDNF), both of which are associated with higher levels of brown fat.
Back in about 2007 or 2008, a Swedish team of researchers discovered brown fat
in PET scans in less than 5% of the human population. That 5% is the portion of the population that is still getting cold. If you do about two weeks of regular cold plunge therapy at temperatures cold enough to trigger the gasp reflex, your body will begin to make new brown fat for non-shivering thermogenesis to defend your core body temperature in the cold.
In How to Increase Brown Fat?, I explain how when you're first starting off with cold plunge therapy, you should go cold enough to gasp and long enough to shiver, especially if you are wanting to experience the full range of psychological and metabolic benefits. Shivering is your body's secondary defense against heat extraction. The first is vasoconstriction, which shuts off the circulation to your extremities so that you lose less heat through the blood. When your muscles begin to tremble, they generate heat to defend your core body temperature. But after you've done this for about two weeks, your muscles will not shiver in the same way. This is because mitobiogenesis is taking place in select fat cells that get packed with mitochondria to fuel something called non-shivering thermogenesis. This is brown fat.
People used to think that there is no such thing as brown fat in an adult human being, but both infants and children have it. We used to believe that adults just grew out of it, and we realize now that that's not true.
That is to say, getting in the cold and recruiting brown fat is a way of protecting your brain, either from injury or damage due to addiction or chemical dependency. It is a way of strengthening your brain that goes beyond the metabolic benefits that might come in handy if you're with anxiety, depression or any of the other mood disorders that are characteristic of the people who find themselves struggling in the winter, for example with seasonal affective disorder, or find themselves feeling low.
Neurotransmitters respond to cold
In Love in The Ice Bath, I described the hormones and neurotransmitters that are released into the bloodstream in response to cold stimulus. These include the feel-good neurochemicals like dopamine and norepinephrine, and also bonding and attachment hormones like vasopressin and oxytocin.
It is impossible to be in a bad mood when there is three times the levels of normal dopamine coursing through your bloodstream.
The release of these hormones and neurotransmitters is initiated by the sympathetic division of the autonomic nervous system, which coincides with the gasp reflex. That activation is better known as the fight-or-flight response, which can also happen when someone with post-traumatic-stress-disorder (PTSD) is triggered by an event that causes a fearful emotional reaction (like panic or anxiety) that they've experienced in their past. When there is an event that triggers your sympathetic nervous system, the body responds like it's in danger, even without the memory of the event. This activation of the sympathetic nervous system is an involuntary reflex. In response, your hypothalamus, adrenals, liver, and body reacts to prepare you for action.
An ice bath will snap you out of your anxieties about the future, erase your regrets and shame about the past, and bring you to your present moment better than anything else.
However, after about 30 or 45 seconds of structured breathing while immersed up to your neck in ice water, the gasp reflex subsides. As the new neurotransmitters and hormones begin to reach the brain, something else takes over.
The dive reflex improves vagal tone
All mammals are wired for what's called the dive reflex, which coincides with activation of the parasympathetic division of the autonomic nervous system, which controls rest and digest functions. The interplay of these two divisions of the autonomic nervous system, the sympathetic and the parasympathetic, helps explains the third mechanism by which cold plunge therapy can help resolve mood disorders. The dive reflex slows down heart rate and causes the brain waves to slow into a meditative state. This in involuntary, and likely prepares your body for an extended trip into the cold water, which likely helped our ancient ancestors fish and forage for food underwater. Even though you might be experiencing cold thermogenesis via shivering or activation of brown fat, your breathing, brain waves, and heart all typically slow down in response to the dive reflex.
The dive reflex is actuated via the vagus nerve(s), and that activity can improve or strengthen the action of the parasympathetic division. That capacity for calming is sometimes called vagal tone (or vagal drive). In Precooling Speeds Recovery, I talked about the way that using an ice bath prior to a workout will strengthen vagal tone and speed recovery from the exercise. That's because vagal tone is essential for recovering from stress. For example, Vagus Nerve Stimulation explains how you can actually release anxiety through electrostimulation of the vagus nerve(s) & speed relaxation. Moreover, this activation of the sympathetic, followed by activation of the parasympathetic, allows your body to exercise the autonomic nervous system in a way that we can measure.
Heart rate variability for psychological resilience
The single best physiological measure of psychological resilience is heart rate variability (HRV), which is different from pulse. You probably know that resting heart rate is good indication of cardiovascular health. That is, the faster your heart beats, the harder it is working. When your resting heart rate is low, it means you're in good cardiovascular condition. But that's not what heart rate variability is measuring.
Heart rate variability is measuring the difference between the beats.
It's measured statistically, in microseconds. Every slight change in the body or the environment can cause a minuscule variation in the space between beats of the heart. Even something as simple as a breath, or a thought, requires tiny variations in the demands placed upon the heart.
The higher your heart rate variability, the more adaptive your heart is to changing stress conditions. In Ice Bath vs Cold Plunge for HRV I described the case of a former Australian Special Forces military veteran who increased his HRV from 16 to 75ms after adopting a regular practice of ice baths. There is something about the exercising of both the sympathetic and parasympathetic divisions that seems to create a hormetic stress response that improves psychological resilience to all types of stressors.
There is now more data on HRV available than ever before, as people adopt wearables that report back to them in real time. Each device uses a different method, and they're not comparable to one another. For example, the Oura ring and Biostrap could give you different results for HRV, but that's OK. When you undertake a program to improve your HRV, as long as you stick with the same device and same method of measurements, your results will be directionally accurate.
Cold plunge with friends
Another factor for improved mental health that is probably worth mentioning is the social aspect of the cold plunge. I typically get in my ice bath every day by myself, and I'm fine that way, but if you're doing a cold plunge club, a winter swimming club, or if you're going down to the beach and doing this with other people, you're likely to feel a sense of connection and camaraderie with those people. Perhaps this can be attributed to the vasopressin, or maybe it's the oxytocin, which are sometimes referred to as the bonding hormones. Oxytocin is especially one of the most well known hormones with influences on bonding & attachment in humans, with many researchers characterizing it as the "love" or "trust" hormone (Gangestad & Grebe, 2017).
When these are elevated in your bloodstream and you're in the company of people that you consider friends, you may feel closer connections to your acquaintances with whom you are cold plunging.
If you have the opportunity to ice bath with your partner, or to create a club and do this together with others, you're probably gonna feel that your friendships become stronger and your sense of support and connectivity to those people is deeper. In fact, in Cold Plunge Romance, I wrote about how for me, a partner cold plunge is even better than relationship therapy.
Shiver for trauma release
According to a study done by Shalev et al. (2017), "post-traumatic stress disorder (PTSD) is characterized by the persistence of intense reactions to reminders of a traumatic event, altered mood, a sense of imminent threat, disturbed sleep, and hypervigilance." PTSD can stem from a single isolated event or from prolonged exposure to trauma, such as childhood abuse.
Determining who among trauma survivors will develop PTSD presents a significant challenge (Bisson et al. 2015). According to Peter Levine, PhD post-traumatic stress disorder (PTSD) is more likely when the body is immobilized during stress.
That is, movement during stress protects against PTSD.
When the body is immobilized during stress, there is no somatic resolution and the stress is then held as trauma. "Trembling", another form of shivering, can actually help to release that trauma.
If I'm in the ice bath and find myself anxious or upset, that is when I shiver the most- and it's not because I don't have the brown fat to keep myself warm in the cold water. It's because the stress my body is holding onto has yet to be resolved. The shivering helps my nerves reset, so I can face whatever my concerns are with confidence. Q: Should I Shiver in the Ice Bath? provides more details into this mechanism. If you are looking to improve your mental health, try a routine practice of cold plunge & observe how your mood changes over time. You may not only find your spirits lifted & receive a boost in endorphins along with it, but your mental resilience will also strengthen as you adapt to the challenges that ice baths bring.
References
Bisson JI, Cosgrove S, Lewis C, Roberts NP. Post-traumatic stress disorder. Bmj. 2015 Nov 26;351.
Gangestad SW, Grebe NM. Hormonal systems, human social bonding, and affiliation. Hormones and behavior. 2017 May 1;91:122-35.
Shalev A, Liberzon I, Marmar C. Post-traumatic stress disorder. New England journal of medicine. 2017 Jun 22;376(25):2459-69.
About the Author
Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.
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