Eleven minutes. Fifty-seven minutes. These are the numbers Huberman keeps coming back to, and they deserve more attention than they typically get. Not because the numbers themselves are magic — they're not — but because they represent something rare in wellness culture: a specific, testable dose. Most health advice tells you to "do more" or "be consistent." This tells you exactly how much, and the science behind it is solid.
The cold exposure number comes from Susanna Soberg's work, published in Cell Reports Medicine. Eleven minutes a week — split into sessions of two to three minutes — is enough to measurably increase brown fat density in adults. We have a separate article on her research in our knowledge base, and what strikes me every time I read it is how modest the dose is. You don't need heroic ice baths. You need eleven uncomfortable minutes, distributed across the week. That's it.
Across the 700-plus articles and 2,300-plus academic papers in this knowledge base, one pattern emerges again and again: cold and heat work through completely different mechanisms, but they reinforce each other. Cold activates brown fat, spikes catecholamines, floods your system with dopamine — 2.5 times baseline, according to Huberman. Heat activates heat shock proteins, clears misfolded cellular debris, and drives cardiovascular adaptation that mirrors aerobic exercise without the joint impact.
When you combine them, you're not just adding the benefits together. You're oscillating your physiology between two opposite states, and that oscillation itself appears to be the signal. A 2025 paper in our database on Finnish sauna and cold water immersion found that the contrast protocol — heat followed by cold — produced cardiovascular adaptations that neither stimulus produced independently to the same degree. The stress is the medicine. The swing is the point.
The timing of cold relative to strength training. Huberman is clear: do not cold immerse within four hours of a resistance session if muscle growth is the goal. Inflammation is the signal your muscles use to adapt and grow. Cold immersion suppresses that signal. You're essentially hitting the mute button on the message your body is trying to send itself.
This is where I see people make costly mistakes. They finish a hard gym session, jump in the cold plunge because they feel it's "recovery," and then wonder why their strength gains stall. Use cold for performance and metabolic goals. Use it before training, or on rest days. Save the post-workout window for your body to do what it needs to do uninterrupted.
We have a paper in the database on peroxisome-derived lipids and adipose thermogenesis — dense reading, but the finding is striking. Cold exposure doesn't just activate existing brown fat. It induces mitochondrial fission in adipose tissue, literally increasing the number of mitochondria in your fat cells. You're not just burning more energy. You're building a more capable furnace, at the cellular level, through the simple act of getting cold.
My recommendation: start with the eleven minutes. Three sessions across the week, three to four minutes each, cold enough that you want to get out but safe enough that you don't have to. Track how you feel over three weeks. Then layer in the sauna. The contrast will do what the individual protocols can't do alone.