I think sustained physical and mental stress have a large effect on health and longevity.
I have heard various theories about stress, some saying that it's actually good for one to be stressed.
But as anecdotal information, I know that whenever I'm stressed I feel awful. So I tend to agree with you.
On another note, there's a medical show on Fox tv shown every Sunday morning, featuring a doctor giving viewers current medical information and answering questions. One of the things the doctor always says is "every medicine contains a little bit of poison."
When I watch tv and see ads for certain medications, and the warnings and caveats take up more time to speak of than the help the medicine provides, I'm not surprised we're dying earlier.
Since the weakening of government protective agencies by Ronald Reagan and other Republicans, medicines are permitted the side effects of which would horrify a panel of Spanish inquisition torturers.
In one particular case, a medication to help shrink an enlarged prostate can cause gynomastia and other highly undesirable side effects. A cosmetic to increase the length of eyelashes(!) may cause blindness.
When you hear our Republican presidential candidates speak of the free market, this laissez-faire kind of "to hell with the consumer" attitude is what they are speaking of, although they disguise it as criticism of "government interference."