[kotyk]

Huberman has a few great episodes breaking down the biology of our circadian rhythms — and that really changed how I think about showers.

My rough takeaway:

- *Cold morning showers* are great for kickstarting dopamine and norepinephrine, putting mild stress on the body to wake it up and drive early-day focus. - *Warm evening showers*, on the other hand, help relax the body, dilate peripheral blood vessels, and prepare for sleep.

Bonus trick: if you combine a warm evening shower with soft, low amber light instead of overhead LEDs, you can preserve melatonin flow and not accidentally “wake up” your brain with harsh lighting.

In short — I think both are useful. Just for opposite reasons.