I'll say it again - shift work sucks. It is physically demanding working in the WOCL against human physiology, and shift work has proven to reduce longevity IN NON-AVIATION WORKERS. I'd argue professional pilots are healthier than the population at large, and we have more opportunities to exercise than many other types of workers IF we prioritize that as part of our routine. To that point, there has been no study of professional pilot lifespan in the last 3 or so decades and none that centers on cargo pilots.
I'll also reiterate a refrain I've said dozens of times here - "This job ain't for everybody."
What I do think there is, however, is a niche here for just about everybody. It might take a little bit of seniority to find it though, but seniority here has moved at a historic rate in the last 6 years due to significant fleet/pilot group growth. 2014 hires are now above 50% seniority and a mandatory retirement wave looms over the upcoming decade.
All that said...
With the movement going on in the industry right now and <2yr narrowbody upgrades at the Big Three, "golden handcuffs" aren't really at play like they were 5-10-15 years ago and life is too short to be miserable in your career.
"Sleep, exercise, eat decently healthy."