If you're 104 and takes long walks everyday that's the more extreme element rather than cold showers. But sure a great morning routine with the adrenaline boost from cold water might give you the edge to actually take that morning walk.
there is no secret to longevity, at least not one "the secret" key to everything.
the real secret to longevity is recreating the conditions are bodies function best at and upholding those conditions. because our environment is so radically different from the past, this requires a lot of discipline, pondering, and paying attention most of all.
our bodies evolved for a certain environment, and recreating that environment would do us good. (i believe that careful people lived long lives pre-industry.)
some of these conditions are regular exercise, occasional starvation, following environmental queues, supporting a healthy biome, and avoiding stress.
our approaches to health today are comical in their attempt to simplify and reduce a billion-year-old continuously-evolving system down to one or two simple concepts while ignoring all the harm we do to it at the same time.
to use a car analogy, it's sort of like throwing away your automobile's maintenance manual and saying, "i heard the key to car longevity is changing the oil often", and filling up the engine with olive oil.
There's a premise here that deserves scrutiny -- that longevity (beyond reproductive age) has evolutionary benefits. Nature may well prefer that older individuals die off.
longevity has many evolutionary benefits, the biggest one being that older generation can pass on survival-essential knowledge and skill to the younger generations.
this process exists not only in humans, but in most animals, and the improvement is continuous, it never stops.
furthermore, the longest-surviving individuals (with the tightest bonds) are able to pass on the most survival knowledge to their descendants, creating an exponential effect.
Fair point. But it has evolutionary disadvantages, too. If food scarcity has been a challenge across evolutionary scales (which seems reasonable), then the utility function might prioritize scarce resources for the reproductively fit.
My point is that it's challenging to make a watertight argument that "we should do X, because evolution suggests that we should."
> Fair point. But it has evolutionary disadvantages, too. If food scarcity has been a challenge across evolutionary scales (which seems reasonable), then the utility function might prioritize scarce resources for the reproductively fit.
That's typically how it has been prioritized, if food scarcity was an issue.
> My point is that it's challenging to make a watertight argument that "we should do X, because evolution suggests that we should."
Sure, but most of the time I would bet dollars to donuts that environmental variables we evolved in will be better for us than new ones, just like in well-aged software time-tested inputs are more likely to work than new stuff you've never tried before.
A great example that's relevant today is that people in the West over 60 yo remember society pre-Social Marxism.
There's a lot of their Youtube videos on how successful families are constructed for the benefit of individuals and society, which is a "lost art" today.