Our long time member Tirademan (R.I.P. Scott McClean) compiled this extensive archive of Sasquatch related newspaper articles and donated it to the BFF before his passing. The earliest articles in this collection are from 1818 in Florida, 1877 (Australia), 1884 (Canada) and 1764 (Europe).
There is little likelihood that BF populations in the Appalachians and PWN have intersected since the European settlers surged Westward. They probably did not before that either because of the distances involved and isolation by the great American plains. In other words there are now pockets of diverse populations of BF that have several and perhaps hundreds of generations of genetic isolation. One can expect increasing genetic diversity and differences in appearance between distantly isolated groups. Perhaps the ones in Florida were isolated first because of the flow of settlement in the East Coast? The last to be isolated would be the ones in the PNW since that is were European settlement happened last. Just that might explain why those in the PNW may be more genetically healthy because interchange of individuals could still be conducted between various BF tribes. Genetic health would promote less genetic deviation and differences in appearance.
I do believe we are looking at individual variation and maybe differing genus like trout populations in the east and west for instance based on possibly regional influences/barriers, but many of these guys may be trim like the most athletic NFL linebackers; I suspect you could call many of them massive.
The way sasquatch have been viewed hauling away white-tails, razorbacks and elk I would say they have muscle mass above and beyond for sure in many cases. I was more talking height here than anything. My night-time education involved a 4 1/2 to 5 1/2 footer and I did not get the impression it was a juvenile sent on a counting coup adventure to directly approach me. It was not alone that night though and two others may have been on a counting coup mission. Aging in sasquatch is a little too far out there for me and others to probably speak to however. Based on some TN sightings they do suffer from bone infections or strokes, probably dental problems just like humans.
I'm primarily in the southern appalachians now and have given thought as to how a wide body, tall sasquatch fits nicely in the North Cascades but maybe not so much in the Blue Ridge, having spent some time on both coasts now.