My anecdata with my parents generation suggests the same. Quite often retirees I know grow 'old' quite overnight after retiring. One or two even died soon after

My anecdata with my parents generation suggests the same. Quite often retirees I know grow 'old' quite overnight after retiring. One or two even died soon after retirement with no prior illnesses. The total absence of responsibilities is what I contribute it too. You don't want too much stress in your life, and winding down a bit at 60+ seems legit, but a sound daily rhythm and outside expectation just seem to fit with being a social animal. They all want to see the grandkids more but end up mostly being entertained while doing groceries. Obviously a massive simplification of other peoples real lives, but the fittest 60+ yr olds I meet are usually (partially) employed. I totally acknowledge that it is more feasible for consultant-type white collar jobs and that on it's own is a subset with different health characteristics, so I'd happily learn of more research in this area.