Research Blog

March 15, 2024

Biological Age: Part 1 - What is Biological Age?

Welcome to the ODX series on "Biological Age: A True Measure of Health." This series will review the difference between chronological age, which is predictable, and biological age, which varies depending on lifestyle and physiological function at a given point in time. Fortunately, the biological age of our organs and systems can be evaluated and improved upon, if needed, independent of one’s chronological age. The goal is to reduce the risk of chronic disease and dysfunction and optimize one’s healthful years by adopting beneficial habits associated with wellness and longevity.

The ODX Biological Age Series

Dicken Weatherby, N.D. and Beth Ellen DiLuglio, MS, RDN, LDN

  1. Biological Age - Part 1: What is Biological Age?
  2. Biological Age - Part 2: How to Measure Biological Age: Overview
  3. Biological Age - Part 3: How to Measure Biological Age: Key Biomarkers
  4. Biological Age - Part 4: How to Measure Biological Age: DNA Methylation (DNAm)
  5. Biological Age - Part 5: How to Measure Biological Age: Telomere Length
  6. Biological Age - Part 6: How to Improve Biological Age
  7. Biological Age - Part 7: Optimal Takeaways

Age is just a number, but it means so much to so many...

Chronological age is based on how many years someone has been alive. However, biological age reflects how many of those years were healthy and how many years may lie ahead. The National Institute on Aging states, “Biological age means the true age that our cells, tissues, and organ systems appear to be, based on biochemistry (NIH NIA 2021). Therefore, chronological and biological age can differ depending on an individual’s health status. Chronological age reflects lifespan, while biological age reflects health span.

Biological age may also be called “Phenotypic Age” or PhenoAge.

While chronological age is measured in annual birthdays, biological age can be calculated using blood biomarkers and specific genetic markers, such as those associated with DNA methylation and telomere length.

A higher biological age is associated with inflammation, disrupted DNA repair, and impaired mitochondrial function, leading to altered energy metabolism and accelerated aging. Biological age reflects organ function and physical capacity. Biological age can help predict susceptibility to chronic disease and even all-cause mortality independent of chronological age (Levine 2018).

Biological age is considered a valuable marker for identifying high-risk populations who will be increasingly susceptible to chronic disease and mortality as they age chronologically. Research suggests that age and cardiovascular disease, a primary cause of death, are closely interconnected and may share mutual pathways. However, accelerated biological aging can be linked to cardiovascular dysfunction, disease susceptibility, and a more significant number of chronic disorders in subjects with coronary artery disease despite their chronological age. Biological age calculations may be beneficial in predicting cardiovascular risk in young subjects with a lower chronological age than traditional cardiovascular patients (Ma 2022).

The main factors that can be used to evaluate biological age include:

  • Blood Biomarkers
    • Nine primary biomarkers: Albumin, alkaline phosphatase, creatinine, C-reactive protein, fasting glucose, lymphocyte %, MCV, RDW, and white blood cell count
  • DNA methylation
  • Telomere length

Higher biological age is associated with less-than-desirable lifestyle habits, including poor sleep hygiene, unhealthy eating habits, higher body mass index, nicotine exposure, limited physical activity, unhealthy blood glucose levels, blood lipids, and blood pressure. Fortunately, biological age can be reduced by optimizing these factors (Zhang 2023).

Photo by Jane Doan from

It is important to note that even small steps toward a healthy lifestyle can improve biological age and reduce chronic disease risk.

Optimal Takeaways

  • Chronological age reflects lifespan, but biological age reflects health span.
  • Biological age can be calculated using commonly available blood biomarkers and specialized testing such as DNA methylation and telomere length.
  • A higher biological age is associated with dysfunction, chronic disease susceptibility, and increased all-cause mortality.
  • Beneficial lifestyle habits, such as a healthy diet, regular physical activity, adequate sleep, and effective stress management, can optimize biological age.
  • Even small steps toward a healthy lifestyle can make a difference in biological age.

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Levine, Morgan E et al. “An epigenetic biomarker of aging for lifespan and healthspan.” Aging vol. 10,4 (2018): 573-591. doi:10.18632/aging.101414 This is an open-access article distributed under the terms of the Creative Commons Attribution (CC BY) 3.0 License.

Ma, Qiong et al. “Association between Phenotypic Age and Mortality in Patients with Multivessel Coronary Artery Disease.” Disease markers vol. 2022 4524032. 13 Jan. 2022, doi:10.1155/2022/4524032

National Institutes of Health. National Institute on Aging. The epigenetics of aging: What the body’s hands of time tell us. March 26, 2021.

Zhang, Ronghuai et al. “Association between life's essential 8 and biological ageing among US adults.” Journal of translational medicine vol. 21,1 622. 14 Sep. 2023, doi:10.1186/s12967-023-04495-8

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