I've known and flown with a lot of older pilots, many of whom retired doing freight, and some of whom kept going well after 65 as they moved to the FE seat. One of the most sprightly that I knew was 75 years old, and could beat me up the stairs to the main deck hauling a suitcase that was nearly as big as him.
He'd been doing freight as long as he could remember, which was longer than I could remember, as it was well before I was born.
I knew others that dropped dead long before, some from liver problems from excess drink, some from heart problems from excess food, and others simply because perhaps it was their time.
We all have a time.
Whether it falls before or after 65 doesn't have a lot to do with cargo, but a lot to do with the individual, be it a their genes or their disposition. A poor carpenter blames the tool.