What Josh Keron is describing in this video isn't complicated, but it is profound. The core claim is straightforward: cold water immersion triggers a cascade of neurochemical and metabolic responses thatâwhen practiced consistentlyâimprove mood, metabolism, and resilience. The 2.5-fold increase in noradrenaline is the headline figure, and it's real. But I want to talk about what that number actually means for the people sitting on the fence about this practice.
Noradrenaline isn't just a stress hormone. It's a signal. Your body is saying: pay attention, mobilize resources, be here now. In the knowledge base, we have Bryan Chauvin's interview where he talks about cold plunging as a daily anchorânot because it's pleasant, but because the signal it sends wakes up systems that modern life has quietly put to sleep. The article on cold plunge versus sauna for aging adds another layer: noradrenaline from cold exposure doesn't just sharpen focus, it also plays a role in fat oxidation and vascular health. The same molecule doing multiple jobs simultaneously.
The 11-minute weekly threshold is one of those rare numbers in this field that's actionable without being arbitrary. Split across two or three sessions, that's roughly four minutes per plunge. That's achievable. That's sustainable. And across the research we have indexed, the dose-response curve here is consistentâyou don't need extreme duration to get meaningful metabolic effects. Faf du Plessis talks about this in his recovery protocol: shorter, more frequent exposures outperform sporadic heroic sessions.
Where experts diverge is on the neurochemical piece. The dopamine and serotonin claims are real but context-dependent. Cold exposure doesn't generate these neurotransmitters from nothingâit sensitizes the receptors and changes how your body responds to them afterward. This is the same mechanism behind the endorphin-dynorphin system Rhonda Patrick describes. The discomfort primes you for greater reward.
The 36% heat loss figure from head dunking is something most people overlook. The scalp and face have dense vasculature close to the surfaceâthey're enormously efficient at dissipating heat. This means that people with physical limitations, injury, or genuine cold sensitivity have a legitimate entry point into this practice that isn't full-body immersion. Dunking your head, face submersion, or even a cold face splash after a warm shower engages the same thermoregulatory response at a lower barrier to entry.
Start at the temperature your body finds genuinely challengingânot torturous. Stay for two to three minutes. Get out. Warm up deliberately and slowly. Do that two or three times a week and don't skip it when you feel like skipping it, because that's precisely when the protocol is most valuable. The adaptation doesn't happen in the cold. It happens in the hours afterward, when your nervous system recalibrates.
The surprising connection: cold exposure and breathwork are training the same underlying system. Your ability to stay calm under the cold shockâslowing your breath, refusing to hyperventilateâis the same skill that determines how you respond to stress in every other domain of your life. The plunge is a rehearsal for equanimity. That's not woo-woo. That's neurology.