Here's what most people get wrong about cold exposure. They step out of the plunge, feel that electric surge of energy, and think: this is the whole point. That rush of catecholamines — dopamine, epinephrine, norepinephrine — flooding through the system. They feel invincible. Sharp. Alive.
And then, a few hours later, they wonder why they feel flat.
Huberman's core message here is deceptively simple: the trough is not a failure. It's physics. Every significant catecholamine spike is followed by a dip. Not sometimes. Always. And the people who understand this — who accept the trough, relax through it, and let the body return to baseline — are the ones who actually benefit from cold exposure over time. The people who fight the trough, or keep chasing the spike with more stimulation, are the ones who burn out.
This maps perfectly onto what we see across dozens of studies in the knowledge base. The dopamine-reward research is unambiguous: cold exposure produces one of the largest acute dopamine increases measurable in the body — comparable to cocaine, without the addiction or the crash. But the word "comparable" deserves scrutiny. Cocaine's dopamine spike is so steep and so artificial that the crash is brutal, destabilizing. Cold exposure's spike is more gradual, more natural, and the trough is proportionally gentler.
But it is still a trough. And if you're stacking cold plunges with caffeine, with high-intensity training, with other catecholamine-spiking behaviors — you're not amplifying the benefit. You're deepening the crash.
What I find most valuable in Huberman's framing is the acknowledgment that protocols are not one-size-fits-all. He says it plainly: people who are naturally hyperactivated — high energy, spontaneous movement, leaner builds — may actually benefit more from sauna than cold plunge. More stillness, more heat, more parasympathetic activation. Not less discipline. Different medicine.
This aligns with what Wim Hof himself has said repeatedly: cold is a teacher, not a prescription. It reveals who you are. If you're already running hot neurologically, cold might amplify that in ways that aren't serving you. Heat teaches surrender. Cold teaches activation. You need to know which lesson you actually need.
Daily self-assessment before reaching for any stimulation tool — cold, caffeine, exercise — is genuinely underrated as a practice. Ask yourself: where am I on the spectrum today? Am I depleted, or am I already wired? That single question, answered honestly, will do more for your energy management than any protocol stack.
If you're depleted: skip the plunge. Take a warm bath. Rest. Let the body recover.
If you're already running high: consider finishing your shower warm, or swapping the plunge for a long sauna session. Let the heat slow you down. The parasympathetic nervous system needs training too.
Here's what caught my attention in the broader research: the 2021 Afadin brown fat study. When mice were cold-exposed, Afadin protein expression in brown adipose tissue spiked significantly — driving thermogenesis, increasing UCP1 activity, burning fat to generate heat. This is your body adapting to the cold stimulus at the cellular level. But the adaptation only works if the cold stress is intermittent. Continuous cold suppresses the adaptive response. The trough isn't just psychological recovery — it may be the window during which the body consolidates the biological gains from the exposure.
Rest after cold isn't laziness. It might be where the real work happens.