How old are you?
Well, that depends on what’s being measured.
Aging is the process of getting older. Old age is less defined. People do not become "older" or "elderly" at any specific age.
Traditionally, age 65 has been designated as the beginning of older age, but as we experience longer life spans, this marker will likely be increased. For example, full retirement age for Social Security benefits has grown from age 65 to age 67 for those born in 1960 or later.
Some say, "age is just a number" referring to the fact that person's age doesn't define who they or what they can still achieve. There are many ways to measure age, some more scientific than others.
The simplest and least scientific is chronological age, or the amount of time a person has been alive. For example, today I am 66 and next year at this time I will be 67. However, if you lined up every 66-year-old on this planet there would be significant differences in health and life expectancy, so chronological age is not always the best indicator of aging.
Biological age is a measure of how old a person's cells are, and how well they are functioning. Biological age can vary from person to person, and is influenced by factors like genetics, lifestyle, and stress.
New studies have shown that added sugar in our diet can cause our cells to prematurely age, even if a person’s diet is otherwise healthy.
Researchers found that eating a vegan diet for eight weeks is associated with reductions in biological age.
Individuals who experience grief over losing a close loved one were more likely to experience accelerated biological aging compared with people who have not experienced loss.
And stress can increase biological age.
I think back to pictures of my great grandparents who emigrated here from Europe. If I had to guess their age in those pictures, I would say they were at least twenty years older than they were. I can only imagine the lifestyle challenges and stressors they faced moving across the world and forging a new life in a foreign land.
Another marker is cognitive age, which is the process of changes in thinking, learning, and remembering. Cognitive age is an indication of overall brain health. Medications, poor vision and hearing, sleep deprivation, and depression also can interfere with brain function, and thus there can be wide variations in cognitive age even when individuals are the same chronological age.
Fitness age is an estimate of how fit someone is compared to their actual age. Think of Arnold Schwarzenegger (age 77) or Helen Mirren (age 79) as examples of those whose fitness age is likely lower than their chronological age.
Perceived age is how old someone looks to others, or how young or old they feel, both physically and mentally. Many people have perceived ages that are younger than their chronological age. Let’s be sure to thank the anti-aging industry, Spanx® and the myriads of other accoutrements available to make us look younger.
The work ability index assesses the physical and mental demands of work and how well a worker can perform them. It was originally used to conduct research on gradual retirement age in different occupational groups. For example, the work ability index helped to determine a mandatory retirement age of 65 for commercial pilots.
And lastly, there is the frailty index which is used to measure the health status of older individuals, serving as an indicator of vulnerability to poor outcomes. This index, for example, would suggest that for a 90-year-old man with multiple chronic conditions an aggressive intervention like CPR would generally not result in a good outcome.
Worried about how old you are in any models? The good news is research also shows that positive beliefs about aging can promote longevity. So, do what you can to age well and let positive thoughts stay top of mind.