Cold showers have very real effects on the human body.
> Deliberate cold exposure causes a significant release of epinephrine (aka adrenaline) and norepinephrine (aka noradrenaline) in the brain and body. These neurochemicals make us feel alert and can make us feel agitated and as if we need to move or vocalize during the cold exposure. Cold causes their levels to stay elevated for some time and their ongoing effect after the exposure is to increase your level of energy and focus, which can be applied to other mental and/or physical activities.
I tried taking cold showers and I can guarantee that "some time" is actually just 5 minutes or so. Not worth considering the risk of strokes and heart attacks.
Mr Bowie was talking more about his professional craft - be it writing code, public speaking, or playing rock guitar; going to the edge of your comfort zone in that craft is the way to learn it. I don't think that cold showers are anyone's professional craft, even if they might be beneficial to health and alertness.
> Deliberate cold exposure causes a significant release of epinephrine (aka adrenaline) and norepinephrine (aka noradrenaline) in the brain and body. These neurochemicals make us feel alert and can make us feel agitated and as if we need to move or vocalize during the cold exposure. Cold causes their levels to stay elevated for some time and their ongoing effect after the exposure is to increase your level of energy and focus, which can be applied to other mental and/or physical activities.
https://hubermanlab.com/the-science-and-use-of-cold-exposure...