Sure, age might be nothing but a number, but which number? You actually have two ages: your chronological age and your biological age—and odds are good that they’re not the same.
Your chronological age is the age you’re familiar with; in simple terms it’s how many birthdays you’ve checked off. Your biological age, on the other hand, is how well your body is holding up compared to others with a similar birth date. The former can be measured by ripping days off the calendar; the latter by measuring biomarkers that are linked with getting older, including changes to your DNA and cells.
If you’re looking to optimize your health and ward off age-related diseases, you want your biological age to be at least equal to—but ideally lower than—your chronological age. Fortunately, there are things you can do right now to make that happen and add health to your years.
What is Chronological Age?
Your chronological age is the one you share (or fudge a little) with others: It’s how many years you’ve been alive. We all celebrate a birthday once a year, meaning everyone’s chronological age increases at the same rate.
What is Biological Age?
Your biological age is a trickier to determine. Biological age is how old your cells are and how various diseases and conditions are present (or absent) in your body.
While you can see some external signs of aging (gray hair, wrinkles), biological aging largely happens invisibly inside your cells. And it doesn’t happen at the same rate for everybody.
Your biological age is the one you should really care about, just like you should be prioritizing improving your healthspan over maxing out your lifespan. The older your cells get, the more susceptible they are to becoming senescent, or zombie cells, “undead” cells that stop multiplying and instead of doing their job, hang out in your body and continue to release chemicals that can trigger inflammation.
Zombie cells may be linked to age-related diseases like Alzheimer’s, dementia, and Parkinson’s, as well as cardiovascular disease and cancer.
What Determines Your Biological Age?
A study published in 2021 identified five predictors of biological age: telomere length, composite biomarkers, DNA methylation, transcriptional predictors, and functional age predictors. That’s a mouthful of science speak, so let’s break them down one by one.
1. Telomere length
Every time a cell divides and replicates, caps at the ends of chromosomes, called telomeres, get a little shorter. Research has found an association between telomere shortening and age-related diseases including cardiovascular disease and Alzheimer’s (1).
2. Composite biomarkers
A slew of biomarkers come together to form what’s known as allostatic load (put simply: the cumulative effects of physical and mental stress on your body over time).
Chronic stress takes a toll on your body. Your sympathetic nervous system—the one that controls your “fight or flight” response—gets stuck in the “on” position. The result: allostatic overload, a long-term drain on your body that’s associated with poorer health outcomes and an increased risk of developing conditions such as inflammatory disorders, metabolic syndrome and cardiovascular diseases, depression, and anxiety (2, 3).
3. DNA methylation
We tend to think of DNA as unchanging, but genes can be expressed or turned “off” or “on” in response to environmental factors (like pollution) or illness. In a nutshell, DNA methylation refers to determining whether a gene is flipped to the “on” or “off” position (4).
What does this have to do with aging? When cells become damaged or die, the body creates new cells. And not all cells age at the same rate. Various epigenetic “clocks” analyze DNA methylation to calculate your mortality risk and your risk of developing certain diseases (4).
5. Transcriptional predictors
In other words: genetic expression in genes specifically associated with aging.
Research published in 2015 identified roughly 1,500 genes that have some impact on aging. The scientists made genetic profiles for nearly 15,000 people, looking at predictors of aging including blood pressure, blood sugar, cholesterol levels, and BMI (5)
Looking closely at genes related to aging (in concert with things like determining telomere length) can help you better “predict” (and therefore intervene, if necessary) your biological age.
6. Functional age predictors
Age-related muscle loss is a part of aging and few guys maintain their bench press PB into their later years. But if you lose too much strength (particularly grip strength) and functional fitness, you fall into the frailty zone.
One study found every one-point increase in the seven-point Clinical Frailty Scale corresponded to 21.2% increased risk of death within six years (6).
How Can I Calculate My Biological Age?
There are some at-home and laboratory tests on the market that look at DNA samples from blood or saliva, as well as low-tech online quizzes, which promise to reveal your biological age. Some also claim to predict how quickly you’re aging.
Jack Jeng, M.D., Chief Medical Officer of Hone Health, sees the most promise from tests that use DNA methylation patterns to calculate risk scores.
“More studies need to be done on humans before I would recommend them,” says Jeng. “But I’m hopeful that these tests could help people track how adopting healthy strategies impacts their biological age over time.”
How Can I Lower My Biological Age?
They won’t change the year on your driver’s license, but these smart lifestyle choices may be able to help you turn back the clock.
A recent small randomized controlled trial, published in the journal Aging in 2021, studied the biological ages of 43 healthy adult men between the ages of 50 and 72. The men who completed an eight-week program focused on lifestyle choices such as diet, sleep, exercise, and relaxation decreased their biological ages by 3.23 years compared to the control group, which received no interventions or guidance. But, as the study authors point out, it’s not yet been established whether slowing or decreasing biological aging automatically translates to a lower risk of age-related disease (7).
Here’s what research has found can give your biological age the Benjamin Button treatment.
1. Eat more plants
Participants in the Aging study ate a predominantly plant-based diet, with mild intermittent fasting and restrictions on animal proteins and carbohydrates. A study published in 2022 from Italian researchers found eating a Mediterranean diet or DASH diet was associated with decreased biological age, and theorized that this was possibly due to heavy consumption of polyphenols. Polyphenols are a category of compounds found in plant foods such as fruits and vegetables (8).
2. Work out most days
Men who turned back their biological clocks in the trial published in Aging exercised at least 30 minutes a day, five days a week. A study published in 2017 found adults who participated in high levels of physical activity had longer telomeres than less-active adults, accounting for significantly reduced cellular aging (9). Around 40 minutes of jogging five days a week can be considered a high level of physical activity.
3. Curb stress
While basic research has found exposure to short-term stress can make your cells more resilient, chronic stress does the opposite (10).
Prolonged exposure to environmental, physical, or emotional stressors can age your cells through the release of stress hormones, inflammation, and cellular oxidation. Participants in the Aging study who improved their biological ages performed breathing exercises twice a day to promote relaxation.
4. Prioritize sleep
Men in the eight-week program published in Aging aimed for a minimum of seven hours of sleep each night. Another study found adults who slept less than five hours a night had shorter telomeres than those who slept at least more than seven hours (11). And another small study published in 2015 found even one night of insufficient sleep activated gene expression patterns that promoted biological aging (12).