Even with the finest medical care in the world, as in the case of a king. Actually, the reason average life spans are so much longer now than they were back then is because infant mortality is included in the equation. A 45 year old man at the time of the American revolution in 1776 had the same average number of years to look forward to as does a 45 year old man in 2011 USA. If you want to see a sport where the participants die young look at wrasslin. It is shocking. But that's because they abuse their bodies with drugs, especially massive amounts of steroids.
Joe Grim, the staggeringly inept welter/middle fought , and was hammered by; Johnson Fitz McCartty Holly Stift Dixie Kid McVey Kaufman Maher Walcott etc Yet died two months short of 58,a respectable age in 1939.
There may be some doubt that Joe was hammered by McCarty, I think he may have won, or at least drawn this, strange to say. Haven't researched this myself but I'm sure I read some reliable info on it.
How would any onyone be able to estimate the life span of people who were born in the 1960s - 1990s as 70 years plus.with the lack of exercise and crappy fast food diets of many people.
I wonder if heavyweight champions in general are born to become much stronger than average adults, with greater than average resistance to disease, which enables them to live to the average age they do, even if they take too much punishment from fighting, unhealthy lifestyles, overeating and/or drug and alcohol abuse. There are exceptions. Some of the champion heavies became diabetic and prone to high blood pressure and heart disease at an early age.