"Healthy old people are much more likely to have a lower resting metabolic rate, Ferrucci says, which means that their bodies are still working efficiently. 'They have energy left for other activities,' he says. 'It allows them to do many, many things during daily life.'
The lucky ones also tend to have fasting glucose numbers more typical of people in their 20s. Obesity and lack of exercise increase the risk of insulin resistance, so keeping weight under control and staying active from early adulthood can help there, Ferrucci says. Medications like metformin for people with insulin resistance help, too. 'There's a lot you can do to manage your insulin resistance as soon as you realize it's there.'
Other studies, including the landmark Baltimore Longitudinal Study on Aging, have found that participants' attitude about the inevitable losses of aging matters, too.
'Some of them thought that aging sucks — your friends die, you get disease, you can't do whatever you want, you can't eat and drink what you like,' Ferrucci says. 'But others thought aging was not so bad.' And people who had a positive view of aging at age 40 had significantly less cardiovascular disease later on."
-Nancy Shute via NPR