The two faces of aging: Chronological vs. biological age

What are the factors that influence your health?

There might be a difference between your chronological age and your biological age. Chronological age refers to how long you’ve been alive, whereas biological age refers to how old your cells and tissues are.

It is possible that your biological age is lower than your chronological age if you are in good health and fit for your age. Sedentary lifestyles, chronic illnesses and poor physical health can increase biological age.

Biological age is more reliable than chronological age for predicting disease onset and death. The difference between chronological and biological aging determines your biological age and how it may be possible to lower it.

Chronological vs biological age

It is impossible to change your chronological age. You’ve spent a certain amount of time on this planet since you were born. Despite the wishes of some, you cannot change that.

You have probably met a few people whose chronological age surprised you because they appeared or “seemed” much older or younger than they were. It is possible that their biological age differs significantly from their chronological age.

Genetics plays a major role in how you age. However, research shows that aging can be affected by external factors, such as [1]:

  • What you eat
  • Physical activity
  • Feelings of stress
  • Tobacco use
  • Getting enough sleep
  • Environment (your home, workplace, etc)

Physiological age, also called biological age, is affected by these factors, and the state of your DNA (genetic material) reflects all of them. Biological age may become more important on your medical charts in the future because it can predict things like diabetes or dementia.

You may also be able to slow your biological aging and even become “younger” by making positive changes [2]. Knowing your biological age may motivate you to lead a healthier lifestyle.

How is biological age determined?

How is biological age determined?

Changes in your genetic material determine your biological age. There are two things that researchers consider:

  • Chromosomes’ telomeres
  • DNA Methylation (aging of DNA)


Chromosomes carry your genetic information along each strand of DNA. Their shapes resemble Xs (except for the one that determines male sex characteristics, which appears as a Y). 

On each point of the X (or Y), there is a small telomere structure. With chronological age, telomeres get shorter.

Biological aging and telomeres

Shorter telomeres were associated with:

  • Symptoms of chronic disease
  • Neurodegenerative disease
  • Early death

Therefore, you are biologically older if your telomeres are shorter than someone born simultaneously. In another study, telomere lengthening is thought to reverse aging by maintaining (or adopting) a healthy lifestyle [3].

DNA methylation

It’s common to think of DNA as fixed and unchanging, but that needs to be more accurate. You have many more genes than show up at any given time. Some are turned “on,” and others are turned “off.”

Having a gene turned on means that it is being expressed. For instance, you have a gene that influences your immune system. You may be exposed to environmental pollution or an illness that switches off that gene at some point.

You may become prone to chronic illnesses after that. Genetic changes have affected your immune system. Methylation is the process of turning genes on or off.

Methylation and biological aging research

To determine if DNA methylation is an accurate age predictor, one study examined DNA methylation. A total of 8,000 samples of 51 different tissues and cells were collected by the researchers [4].

Most tissue and cell samples studied had the same chronological and biological ages based on methylation rates. Some, however, did not.

Particular parts of the body age faster than others, according to researchers. For example, healthy breast tissue can be three years older than the rest of your body. An average of 12 years are added to its age if it is close to cancerous tissue.

Using the methylation-based method of determining biological age, researchers can evaluate the risk of breast cancer.

If you have female breast tissue, every five years older you are biologically than chronologically, your breast cancer risk is 15% higher.

What determines your biological age?

Your biological age can be reduced in a variety of ways. They’re generally the healthy alternatives you’ve heard about.

1. Diet

A 2018 nutrition and biological age study suggests that eating a high-nutrient diet can lower biological age [5]. When deciding what foods to buy, researchers analyzed how much nutrition information people regarded. 

As attention is paid, the biological age decreases. Significant differences were found in people who:

  • Are chronically ill
  • Have a family history of chronic disease
  • Have obesity
  • Are older
  • Have a lower education level

In addition, there was a sex-based difference in nutrition data considerations at the grocery store: just under 13% of males thought about nutrition data while 27.5% of females did. According to other studies on diet and biological age, the ideal diet is:

  • Low in calories
  • Plant-based
  • High in fish
  • A Mediterranean diet

2. Physical activity

According to research, high activity levels are associated with lower biological aging [6]. Not all studies agree that increased exercise impacts biological age [7]. Research supports the idea that it does, however.

  • A 2021 study on post-menopausal women showed a slowdown in some biomarkers of age and disease, including cancer [8].
  • A 2022 study showed that altering the diet and adding exercise lowers your biological age more than dietary changes or increased activity alone [9].
  • A 2020 study found that people trained in aerobic exercise were almost 5.5 years younger than sedentary people [10].

Start slowly if you’ve been sedentary and want to increase your activity level.

3. Stress

The biological age is increased by both physical and psychological stress, but both can be reversed. Researchers in 2022 examined the effects of stressors like [11]:

  • Pregnancy
  • COVID-19 infection
  • Trauma
  • Surgery

Stress led to a rapid increase in biological age (measured by DNA methylation). However, it returned to baseline within a few days of removing the stressor.

Speak to your healthcare provider about reducing or eliminating significant stressors in your life. A mental health therapist may be able to help you.

4. Smoking

Smoking causes serious health problems and shortens lifespan [12]. Biological aging is also linked to smoking [13].

As with stress, though, smoking-related age advancement appears to be reversible. When researchers compared current smokers, former smokers, and people who’ve never smoked, they found that the biological age of former smokers was the same as that of non-smokers.

Discuss medication or emotional support with your healthcare provider if you need help quitting smoking.


5. Sleeping habits

Poor sleep quality negatively impacts health and longevity, and your biological age is also increased [14]. Sleeping seven hours a night is recommended for adults. Many people, however, fail to do so.

A lifestyle factor or a sleep disorder may be at fault. Your health also relies on the quality of your sleep. According to researchers, getting more and better sleep can reverse the biological aging it causes.

It may be possible to improve your sleep duration or quality by making minor changes, like going to bed earlier, turning off screens half an hour before bed or decreasing distractions in the bedroom.

If you are having difficulty sleeping, talk to your healthcare provider. It is possible that you have a sleep disorder that requires diagnosis and treatment.

6. Physical environments

Your physical environment includes where you live, work and spend most of your time. You are exposed to air pollution and other contaminants in your environment.

Toxins can accelerate biological aging, however, certain exposures can be avoided or reduced. This may help reverse the effects, according to research.

Despite this, eliminating some of these hazards may be difficult. The good news is that other healthy changes, such as getting more or better sleep, can reverse the aging caused by pollution. Ensure you and your employer follow all safety procedures if you work with hazardous materials.

How to calculate your biological age?

There needs to be a more complex way to calculate your biological age. It takes medical tests and a healthcare provider to determine it accurately. So, to learn your true biological age, ask your healthcare provider about it.

Some websites claim to have biological age calculators, and they may consider some factors that influence your biological age. However, with access to your test results, they’re scientifically valid.

At least one commercial test is available that claims to determine your biological age. In its current price listing, Elysium uses a saliva sample you collect for $499. No scientific evidence has been provided to support the validity of this test [15].

Many websites offer calculators where you can enter the details of a blood test to determine your biological age, such as Ageless Rx and Longevity Advantage.

For this, you may be able to use recent routine test results. There is, however, a possibility that the results of these calculators are inaccurate and may not be valid.

The best action is to consult your healthcare provider, who will help you interpret the results and suggest ways to improve your biological age and overall health.

The chronological age of a person indicates how long they have lived. A person’s biological age indicates how long they are likely to live and whether they will become chronically ill.

To determine your biological age, you must take medical tests for telomere length and DNA methylation markers, biomarkers of DNA changes.

A person’s biological age can be changed, unlike their chronological age. Various factors can affect your biological age, including diet, exercise, stress levels, sleep quality and smoking.

Online calculators and commercial tests claiming to measure biological age may be inaccurate. Ask your healthcare provider for tests to determine your biological age.


The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.