Think of Buddhist monks who can calmly withstand being draped in freezing towels or the so-called “Iceman” Wim Hof, who can remain submerged in ice water for long periods of time without trouble. What if they’re not freaks, though, but have trained their brains and bodies with self-modification techniques that give them cold resistance? Could anyone do the same?
As two neuroscientists who have studied how the human brain responds to exposure to cold, we are intrigued by what happens in the brain during such resistance. These modifications may be relevant for behavioral and mental health, and can potentially be harnessed by anyone.
The body’s drive for balance
Behavioral modification techniques like yoga and mindfulness seek to modulate physiological equilibrium – what scientists call homeostasis. Homeostasis is a basic survival need and crucial for an organism’s physical integrity.
Homeostasis is maintained when peripheral organs (“the body”) collect sensory data and forward it to the processing center (“the brain”), which organizes and prioritizes this data, generating action plans.
It’s the balance between bottom-up physiological mechanisms and top-down psychological mechanisms that mediates homeostasis and guides actions. Our idea is that this balance between physiology and psychology can be “hacked” by training the brain to deal with exposure to cold.
Brain systems for responding to cold
Brain systems for maintaining homeostasis form a complex hierarchy. Anatomical regions in the primitive brainstem (midbrain, pons) and the hypothalamus form a homeostatic network. This network creates a representation of the body’s current physiologic state.
In human beings, an area in the back of the midbrain called the periaqueductal gray is the control center that sends messages about pain and cold to the body. This area releases opioids and cannabinoids, brain chemicals also associated with mood and anxiety. The periaqueductal gray sends these chemical signals both to the body, via the descending pathway that suppresses the experience of pain and cold, and via other neurotransmitters to the brain.
Being severely cold will interfere with rational thinking, a condition that in hypothermia is catastrophic. But one cannot simply imagine a sunny beach to wash away the unpleasantness associated with feeling very cold. In this instance, the “physiological” system outweighs the “psychological” system.
Hof’s self-modification techniques include controlled breathing (hyperventilation and breath retention) and meditation. Breath retention and cold form two physiologic stressors, whereas meditation is a form of psychological control. His self-taught technique appears to change his brain’s ability to deal with cold by modulating pain pathways.
Extending the benefits
Cold exposure appears to trigger a stress-induced pain-relieving response in the homeostatic brain network, already primed by breath retention. The effects are enhanced by focused meditation which generates the expectation of positive outcomes.
Here’s the crucial part: This expectation is likely to extend the effects of stress-induced pain relief beyond immediate cold exposure. It will lead to the release of additional opioids or cannabinoids from the periaqueductal gray. This release can affect the levels of neurotransmitters such as serotonin and dopamine, further enhancing a feeling of overall well-being. This positive feedback loop is implicated in the well-known “placebo effect.”
More generally, techniques such as those Hof uses appear to exert positive effects on the body’s innate immune response as well. We expect them to also have positive effects on mood and anxiety because of the release of opioids and cannabinoids.
At present, millions of people use drugs to help with feelings of depression and anxiety. Many of these drugs carry unwelcome side effects. Behavioral modification techniques that train users in ways to influence their brain’s homeostatic system could someday provide some patients with drug-free alternatives.
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