Understanding the difference between biological age and chronological age - Mayo Clinic Press (2024)

Despite the fact that aging is universal, there is no universal experience of aging. Some people remain active and sharp both mentally and physically well into their 80s or even 90s, while other people begin to experience a decline in their health or quality of life decades earlier.

Researchers used to believe that life span was chiefly determined by genetics — meaning if your parents and grandparents lived long lives, you and your children would be much more likely to as well. However, more-recent research indicates that genetic factors account for only 15% to 25% of aging. As it turns out, graceful aging has a lot more to do with lifestyle than it does with hitting the genetic lottery.

There is also an important difference between how old someone is, known as chronological age, and the overall state of someone’s body, known as biological age. This distinction may help demystify the aging process and allow you to take a more empowered, holistic approach to your health.

“The key word is holistic,” says Francisco Lopez-Jimenez, M.D., M.S., chair of the Division of Preventive Cardiology at Mayo Clinic. “It’s important to focus on a holistic, multifactorial approach to aging and quality of life, rather than focusing on just a number.”

The difference between biological age and chronological age

Both chronological age and biological age are ways of measuring aging and how the passage of time impacts the body.

“Chronological age measures the number of years someone has been alive,” says Dr. Lopez-Jimenez. We use chronological age all the time to celebrate a birthday, fill out a form for a medical appointment or to get a drink at a bar. Everyone born in the same year has the same chronological age, regardless of how old or young they look or feel.

Biological age, on the other hand, isn’t necessarily the same for everyone and can better reflect the diversity of the aging process across individuals. “Biological age captures how a person is aging, according to many different factors and biomarkers,” says Dr. Lopez-Jimenez. Biomarkers are measurements that offer a snapshot of what is happening in a cell or the body. A routine blood pressure assessment, for example, can give a biomarker, as can imaging technology and laboratory tests. Other biomarkers use genes and proteins to assess the body at the molecular and cellular levels.

There is no one biomarker or test that can determine your age. Typically, a number of laboratory-based biomarkers, such as a blood assessment, and clinically based biomarkers, such as heart rate and blood pressure, are taken into account.Technological advances also are being made every day. Mayo clinic researchers found that an artificial intelligence-enabled EKG was able to find the difference between chronological age and biological age — and gaps between these two ages were associated with cardiovascular mortality. There is also research suggesting that studying certain damaged cells — called senescent cells — can help determine biological age.

Even aside from these advanced measures, Dr. Lopez-Jimenez says it’s possible to guess how someone is aging with a physical assessment and conversation. There are appearance-based markers of age, such as balding, hair color and wrinkles, as well as physical factors like mobility, speed of gait and frailty.

“When we talk about the difference between biological and chronological aging, we are talking about how some people age more or less than others,” says Dr. Lopez-Jimenez. “Understanding why this happens will help us unlock how people can live longer and better.”

What can impact someone’s bio age?

In its most basic sense, aging is the result of changes to the body’s cells, typically cell breakdown or deterioration that, in turn, make cells work less efficiently. Over time, these small changes to the cells compound and lead to the physical markers of age, such as wrinkles, as well as chronic conditions or illnesses like heart disease or dementia.

There are a number of factors that impact the speed of cell deterioration, some of which you can control and some you can’t. Though there are many theories on why exactly aging happens, researchers believe genetics, DNA damage, oxidative stress, and telomere erosion on chromosome tips, senescent cells and chronic inflammation all play a part in how the body ages on the cellular level.

Additionally, there are a number of factors outside the body that also can impact aging. Perhaps unsurprisingly, people who experience high levels of stress, use tobacco and drink alcohol, and lead a sedentary lifestyle and consume a low-quality diet are more likely to develop early-onset illnesses and premature death. Likewise, social connectedness can play a big role in biological aging. People who don’t have strong social connections are more likely to be biologically older than their chronological ages, while people with strong relationships are more likely to age well and stay sharp.

It may seem simple, then, to age gracefully or even slow your biological age. But it’s important to remember that not everyone has access to the same resources, such as reliable medical care and well-stocked and affordable grocery stores, or even fresh air and clean water. In fact, research has shown that poverty, pollution and unhealthy living conditions are associated with accelerated biological age and reduced longevity.

The bottom line of healthy aging

Dr. Lopez-Jimenez says small, consistent habits can have a powerful impact both on how you age and the quality of your life in later years. So far, research has shown that maintaining a balanced diet, refraining from tobacco use, getting regular physical activity, managing stress and keeping up a meaningful, well connected social life — or what is more or less common sense for healthy living — allow most people to maintain both quality and length of life.

But keep in mind that healthy aging isn’t about looking younger than you are or even avoiding all illnesses or health conditions — for most people, that simply isn’t realistic. Instead, emphasize the habits and lifestyle that can support your health span, reduce your risk of cumulative conditions, and keep you feeling satisfied, active and able to adapt to a changing (and aging) body.