DEAR DOCTORS: What does the term "biological age" refer to? How do you go about figuring out what your biological age is? I will turn 80 at the end of the year, am physically active and I eat a vegetarian diet. Is there anything else I should be doing to get "younger"?
DEAR READER: When you say you will be turning 80 later this year, you are referring to your chronological age. That's a straightforward measure of how many years someone has been alive.
Biological age, by contrast, is a concept that looks at a diverse range of physiological factors to determine someone's potential lifespan and the likelihood of their developing an age-related illness. Based on these findings, someone may turn out to be older or younger than their chronological age says they are.
There is no universal formula for determining biological age. However, a core group of metrics are typically used. These begin with someone's health history, their family medical history and any existing diseases or conditions. Lifestyle also plays an important role. This includes exercise, mental health, sleep habits, smoking and drinking, muscle mass, grip strength, balance, endurance, social networks and the individual's physical environment.
Also taken into consideration are metabolic health, certain blood test results and specific aspects of cardiac function. These include resting heart rate and how quickly the heart recovers from exertion.
Biological age is also measured at a cellular level. One factor is something known as DNA methylation. This is a biological process in which certain structural changes take place in someone's DNA. These changes affect gene expression and have been shown to have an adverse impact on ageing. Also important are telomeres, which are structures found at the ends of chromosomes. Shortened telomeres are associated with older age.
The concept of biological age is certainly intriguing. Surging interest has led to the marketing of at-home tests that, based on test results from blood or urine samples or a cheek swab, claim to reveal someone's biological age. Theoretically, you take a test, make lifestyle changes guided by the results, then retest to see if they helped. The catch is that no one knows if the tests are sensitive enough to be effective monitors.
There's also the fact that, depending on what's going on at the cellular level, different parts of the body are likely ageing at different rates. Your cartilage may be "older" than your heart, which may be ageing faster than your brain. Outside of the rigours of anti-ageing research, biological age is more of a novelty than a useful metric.
Rather than focusing on the biomarkers linked to ageing, it's more beneficial to look at the big picture. That brings us back to the basics that studies continue to show are important to good health and longevity -- namely, a healthful diet, regular exercise, managing stress, preventive healthcare, getting adequate and good-quality sleep and robust social engagement. The good news is that, from the description of your own habits, it sounds as though you're already hitting those goals. Universal Features Syndicate
Dr Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health.