When I was young, I hated PE. I still hate PE. But at 22, United Parcel Service hired me to unload trailers and air containers. Halfway into my first week they moved me into what they called 'Irregulars' and what everybody else called 'bulk'.
People/companies use UPS (and other shippers) to send things like car parts, styrofoam containers, oversized packages, wood, metal, stuff packed in wood and metal, bars, poles, furniture, etc, etc. None of that stuff can go down a regular package belt in the system. It has to be handled manually - by bulk/irreg drivers inside the hub. It has to be unloaded, loaded on to a bulk train and then unloaded at the outgoing trailers or air containers so the loaders there can load it.
So at 22, 110lb me is handling this stuff. Then a few years later UPS starts an over-70lb service. By 1999, at 29 years of age, I am throwing 150lb packages from waist height on to belts that are at shoulder height. I am equal parts proud and regretful that I was capable of doing this. Proud because I could, regretful because of the toll that all that took on my body. Even then, I speculated what would happen later on.
But with a dead end there at UPS, I got in to graphic design. That put me in an air conditioned/heated office and sitting in a chair every day. But it had to do with computers and not manual labor in a non-temperature controlled warehouse.
I used to be quite agile. Now years of sitting has resulted in high-blood pressure and the meds to treat it. I doubt I could lift much over 50lbs for long. But the biggest thing is that it's hard to sit comfortably and lie down comfortably. A result of the constant twisting and turning while moving 70lb plus packages in my 20s. That is the end result of the physicality of that job at UPS.
I don't whine about it much except to myself though. I met my wife at that job and we've been married for 28 years now, with two kids (22 and 17) and a home (and the mortgage for it).
The doctor has long told me I need to be walking a minimum of 30 minutes a day. I have bursts of activity for a while where I do that, but it's never consistent. Right now I have to walk or call an Uber. Our car died a month ago and its not getting fixed and I do not see a new car anytime soon to replace it. Fortunately, I am still capable of getting moving.
I just got to do more.