How different is your chronological age vs. biological age?

October 28, 2026
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Nicole Pajer
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Nicole Pajer
MEDICAL REVIEWED BY
Summary

Two people can celebrate the same birthday while their bodies age very differently. Biological age aims to capture that difference, but the number can vary depending on how it’s measured and can only tell you so much. Proactive care, including imaging and blood biomarker testing, can help you establish a baseline and track specific areas of your health over time, while balanced nutrition, regular movement, and consistent sleep can support healthy aging.

How different is your chronological age vs. biological age?

If you share a birthday with someone, that doesn’t automatically make you the same age. Stick with us: Yes, your chronological age is the same, but your biological ages can be very different. 

So, what is biological age? Here’s a quick rundown: Your chronological age is roughly the number of candles on your birthday cake—it’s the time period since your birth. Biological age, on the other hand, is an estimate intended to reflect aspects of your body’s physiological state or age-related molecular changes influenced by genetic, metabolic, and environmental factors. Biological age is now being used to better understand one’s health span, a term that describes the number of years you live in good health free of major disease. 

It’s common for chronological and biological ages to differ, so understanding how biological age is estimated and which modifiable factors may influence it can be helpful when planning for the years ahead.

How is biological age measured?

There’s no single universally accepted way to measure your biological age, but there are several ways researchers and scientists go about doing it.  When it comes to how to calculate biological age, blood biomarkers, physiological measures, body composition, and other indicators are all used, but with no consensus as to the best approach.

Related: Why you should be tracking your body composition

Many biological-age tests begin by comparing how your body functions with data from other people around your chronological age. The result estimates whether your physiology appears older or younger than that peer group. These estimates have been associated with future health outcomes. In one study published in Aging Cell, the fastest agers had up to a 17% higher risk of developing at least one health disorder and a 54% higher risk of mortality compared with the slowest agers.

On the other hand, some models use familiar health indicators such as blood pressure, waist circumference, pulse, body weight, handgrip strength, hearing, and vision. Others incorporate blood markers such as glucose, cholesterol, triglycerides, inflammatory proteins, and red and white blood cell counts. More specialized approaches may also evaluate telomere length, epigenetic changes, genetics, or mitochondrial function, where an algorithm combines the selected data points to produce an estimated biological age.

That wide range of methods helps explain why two tests may give you different answers. Online calculators, at-home kits, laboratory tests, and smart scales do not all measure the same things. A smart scale may account for body composition, for example, while leaving out blood biomarkers, physical function, and information about your internal organs. Before putting too much weight on the number, it’s worth looking at what the test measures and what it leaves out.

Biological age can offer useful insights into how your body is aging, but its reliability depends on how it's measured.

Can you reverse your biological age?

We all age, but there is room to improve habits that may influence many aspects of your health, including your organs and tissues. While there is no treatment or promise to completely prevent disease, some health factors associated with biological age are modifiable. 

Here are a few habits to consider: 

Prioritize a balanced, nutrient-dense diet: A four-week study of adults ages 65 to 75 found that semi-vegetarian and higher-carbohydrate eating patterns were linked to a lower biological-age estimate over the short term. Researchers do not yet know whether those changes last, and the findings do not suggest that everyone should give up animal foods. According to the World Health Organization, a practical place to start is with variety: fruits, vegetables, beans and lentils, whole grains, and enough protein from the plant and/or animal sources that work for you.

Stay active: Exercise itself is associated with slower biological aging. But cutting sedentary time matters, too. Research shows that walking 1,500 additional steps per day or spending three fewer hours sedentary was associated with a lower biological age. Each additional five minutes of moderate-to-vigorous physical activity per day was also associated with lower biological age across the study.

Sleep: The sweet spot for sleep and biological aging is 6.4 to 7.8 hours of sleep per night, according to one study. Too-short of sleep is a stressor to the body and pro-inflammatory, while long sleep may indicate underlying health problems.

Avoid tobacco and limit alcohol: Smoking, vaping, and chronic, excessive alcohol consumption have been linked to decreased telomere length, a biomarker of cell aging. These habits produce oxidative stress, inflammation, and damage to DNA.

Related: This is what alcohol does to your body

These healthy lifestyle factors have been associated with a lower risk of mortality and conditions including cardiovascular disease, metabolic syndrome, cancer, and some cognitive and psychiatric disorders. This might be due to how they slow down biological aging, but there’s still a lot we don’t know. What’s clearer is that the more healthy behaviors you stick to, the better off you are. 

There’s no universally accepted way to calculate biological age, but researchers use measures like blood biomarkers, body composition, and physiological indicators to estimate it.

Why one biological-age score isn’t enough

Your health is complex. You have about 80 organs in your body. Your body composition can change over time with age, life events, and hormonal shifts. Your brain and heart undergo structural and functional changes too. Blood biomarkers may change from one year to the next, reflecting shifts in metabolic health, inflammation, organ function, and other areas of health.

Related: What happens to your brain as you age

A biological-age score condenses many inputs into one number. Tracking specific health measures over time can provide more useful context by showing which areas have remained stable, which have changed, and where follow-up may be appropriate. These measures may include muscle volume, visceral fat, blood biomarkers, heart function, brain structure and volume, and organ health.

These measures can also be related. Prenuvo’s internal research analyzing more than 7,500 MRI scans from adults without symptoms found an association between higher visceral abdominal fat and lower brain volume. This was a correlation and does not establish that visceral fat causes brain atrophy or predict an individual’s future brain health. It does, however, illustrate why health measures are often more useful when considered together.

Prenuvo does not calculate or provide an overall biological-age score. Instead, several Prenuvo assessments can help provide information about specific areas of health:

  • Whole Body Scan: Provides MRI screening across major organs and body systems to help identify potential abnormalities.
  • Advanced Brain Health Scan: Uses MRI and NeuroQuant® analysis to assess brain structure, volume, and blood flow to the brain.
  • Advanced Heart Health Scan: Uses MyoStrain® analysis to measure heart muscle motion, providing information that may complement standard cardiac tests where available.
  • Body Composition Analysis: Measures visceral fat, subcutaneous fat, liver fat, certain organ volumes, along with muscle volume and symmetry. Muscle, in particular, has been linked to longevity, making it a valuable part of understanding how your body changes with age.
  • Blood biomarker testing: Provides information about areas including metabolic health, inflammation, blood health, and organ function.

When used together, these measures can provide key insights about different aspects of your health. Of course, this is a lot more data than one biological age number, and you’ll want to know what to do with your results. For one, these results can serve as a personal baseline. As you repeat testing during the following years, you and your healthcare provider can monitor changes in your results, which may help identify areas that warrant follow-up. Since Prenuvo assessments are designed to complement your regular medical care and recommended screenings, you can also talk through your results with your healthcare providers, deciding what you need to act on and when. 

To learn more about a Prenuvo Membership or standalone services, book a call with our Patient Services Team.

FAQ

Can you be biologically younger than your chronological age?

Yes, people can be biologically younger or older than their chronological age depending on the measures and methodology used.

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Is biological age more important than chronological age?

No. Your chronological age is important because it serves as a guide for when you may be at risk for certain diseases. With that information, health agencies set screening recommendations based on your chronological age. Biological age is one number that’s either younger, the same age, or older than your real age, and it does not provide much data or information about areas of your health to change.

What factors are associated with longevity?

There are many areas of health that can affect longevity, but one of the most important may be physical activity. In a study that looked at adults 50 to 80 years old, researchers found that the top predictors of mortality were based on physical activity, including how much movement you get in your waking hours and total minutes of activity per day. 

How can I find out my biological age?

There are a number of consumer technologies that can be used to find your biological age, including at-home blood biomarker kits, online calculators, and smart scales, but these are all limited in the data they gather. Looking at specific measures from lab work, imaging, body composition, and heart and brain assessments can help provide additional information about different areas of your health.

What slows aging the most?

Research shows that a healthy diet, exercise, avoiding smoking, and reducing alcohol consumption are all modifiable lifestyle factors that may help slow aging, decrease the risk of disease, and may improve longevity. Following a greater number of healthy habits has been linked to slower biological aging.

Citations

Ammous, F., Peterson, M. D., Mitchell, C., & Faul, J. D. (2025). Physical Activity Is Associated With Decreased Epigenetic Aging: Findings From the Health and Retirement Study. Journal of Cachexia, Sarcopenia and Muscle, 16(3). https://doi.org/10.1002/jcsm.13873 

Andrews, C. J., Ribeiro, R. V., Gosby, A., Le Couteur, D. G., Raubenheimer, D., Tan, J., Simpson, S. J., & Senior, A. M. (2026). Short‐Term Dietary Intervention Alters Physiological Profiles Relevant to Ageing. Aging Cell, 25(5). https://doi.org/10.1111/acel.70507 

Fahim, M. A., Yao, Y., Tipparaju, S. M., & Xuan, W. (2025). The heart-brain crosstalk in age related cardiovascular and neurodegenerative diseases. Fluids and Barriers of the CNS, 22(1). https://doi.org/10.1186/s12987-025-00700-6 

LEROUX, A., CUI, E., SMIRNOVA, E., MUSCHELLI, J., SCHRACK, J. A., & CRAINICEANU, C. M. (2024). NHANES 2011–2014: Objective Physical Activity Is the Strongest Predictor of All-Cause Mortality. Medicine & Science in Sports & Exercise, 56(10), 1926–1934. https://doi.org/10.1249/mss.0000000000003497 

Lu, W.-H. (2024). Effect of Modifiable Lifestyle Factors on Biological Aging. The Journal of Aging Research & Lifestyle. https://doi.org/10.14283/jarlife.2024.13 

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Organs in the Body: Definition & Anatomy. (2024, December 9). Cleveland Clinic. https://my.clevelandclinic.org/health/articles/organs-in-the-body 

Prenuvo’s AI-assisted research reveals link between visceral abdominal fat and midlife brain atrophy | Prenuvo blog. (2023). Prenuvo.Com. https://prenuvo.com/blog/prenuvos-research-reveals-link-between-visceral-abdominal-fat-and-midlife-brain-atrophy 

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