If you feel apprehension toward a cold shower or cold bath in the morning, you will derive an increased benefit in terms of a sustained rise in adrenaline and dopamine, while avoiding cold exposure immediately after a workout.

noli's read

The idea that intense cold exposure stimulates the release of catecholamines (including dopamine and norepinephrine) is well documented, notably by a seminal study by Srámek et al. (2000) published in the European Journal of Applied Physiology, which observed significant and sustained increases in these neurotransmitters following cold water immersion. The fact that initial apprehension may reinforce the body's response is biologically plausible via activation of the sympathetic nervous system, although the direct link between 'level of fear' and 'magnitude of benefit' remains a behavioral interpretation rather than measured data. Regarding sports, work by Roberts et al. (2015) in the Journal of Physiology does indeed suggest that post-workout cold water immersion can inhibit the signaling pathways necessary for muscle hypertrophy, validating Huberman's caution on this point. This advice is therefore based on solid physiological mechanisms, even if the exact psychological leverage effect remains to be quantified more precisely. The approach is consistent with current literature on the modulation of the stress response.

the sources

1. 1Buijze GA et al. 2016
2. 2Sramek P, Simeckova M, Jansky L, et al. 2000
3. 3Kelly JS, Bird E. 2021
4. 4Roberts LA, Raastad T, Markworth JF, et al. 2015
5. 5Petersen AC, Fyfe JJ 2021