The other test of age is the sitting-rising test (SRT). Sit on the floor, barefooted, with legs crossed. Lean forward quickly and see if you can get … - David A. Sinclair

Small numbers of senescent cells can cause widespread havoc. Even though they stop dividing, they continue to release tiny proteins called cytokines that cause inflammation and attract immune cells called macrophages that then attack the tissue. Being chronically inflamed is unhealthy: just ask someone with multiple sclerosis, inflammatory bowel disease, or psoriasis. All these diseases are associated with excess cytokine proteins.

A study of more than 41,000 metformin users between the ages of 68 and 81 concluded that metformin reduced the likelihood of dementia, cardiovascular disease, cancer, frailty, and depression, and not by a small amount. In one group of already frail subjects, metformin use over the course of nine years reduced dementia by 4 percent, depression by 16 percent, cardiovascular disease by 19 percent, frailty by 24 percent, and cancer by 4 percent.22 In other studies, the protective power of metformin against cancer has been far greater than that.

This might be the least considered societal advantage of prolonged vitality, and it might just be the greatest advantage of all. Perhaps when we're not all so afraid of the ticking clock, we'll slow down, we'll take a breath, we'll be stoic Samaritans.
I would like to emphasize the word "perhaps," here. I will be the first to say that this thesis is supposition more than science. But the small-sample Princeton experiment both followed and portended a lot of other research demonstrating that humans are a lot more humane when they've got more time. All of the studies, though, take stock of how people behave when they have a few more minutes, or perhaps a few more hours, to spare.
What would happen if we had a few more years? A few more decades? A few more centuries?