Biological age tests: Should you get one?

Johnson’s "Project Blueprint" is an extreme example of the burgeoning anti-aging movement. His regimen includes a dizzying array of interventions: dozens of daily supplements, weekly acid peels, collagen-boosting injections, hyperbaric oxygen therapy, and even plasma infusions sourced from his 17-year-old son. To validate these efforts, Johnson relies heavily on various bio age tests, which he asserts have shown his biological age to be 5.1 years younger than when he began, suggesting he is, in essence, aging in reverse. However, this narrative is not without its detractors. A New York Times exposé, for instance, challenged Johnson’s claims, suggesting his biological age may have, in fact, increased by a decade. This stark divergence highlights the ongoing debate and skepticism surrounding the efficacy and interpretation of bio age testing.

Despite the controversies, the "don’t die" crusade, as some call it, is gaining undeniable traction. Bio age tests are now frequent topics on popular podcasts hosted by figures like Peter Attia, Joe Rogan, and Andrew Huberman. A simple online search for "bio age testing" yields dozens of advertisements for mail-order blood or urine testing kits, promising to reveal one’s biological age, aging pace, and other health metrics. With the cost of these tests steadily decreasing, a critical question arises for individuals and health professionals alike: Should one engage in bio age testing, and if so, which tests offer the most reliable insights, and how should the results inform health strategies?

Understanding Biological Age: Beyond the Birthday Candles

At its core, biological age, or "bio age," refers to the functional state of an individual’s cells and tissues, independent of their chronological age—the number of years lived since birth. While chronological age is a fixed metric, biological age is fluid, influenced by genetics, lifestyle choices, environmental exposures, and medical interventions. Consider two 50-year-old men: Chang, who works a sedentary desk job, spends evenings in front of the television, resides in a heavily polluted urban environment, consumes processed foods, and smokes. In stark contrast, Jabari, also 50, exercises several times a week, lives in a pristine mountainous region, avoids smoking, meticulously consumes five servings of vegetables daily, practices meditation, and dedicates his evenings to gardening. Barring extraordinary genetic predispositions, it is reasonable to infer that Jabari’s biological age is likely considerably younger than Chang’s.

The concept of biological age is crucial because it offers a more nuanced understanding of health and longevity risk. A younger biological age is generally associated with a lower risk of age-related diseases and increased lifespan, while an older biological age can signal accelerated decline and heightened vulnerability to chronic conditions such as cardiovascular disease, type 2 diabetes, and neurodegenerative disorders.

The Science Behind Bio Age Measurement: Biomarkers and Epigenetic Clocks

Bio age testing kits aim to quantify this physiological state by measuring one or more biological markers of aging, known as biomarkers. These biomarkers are measurable indicators of a biological state or condition. The scientific community has been developing and refining methods to assess biological age for decades, moving from simpler physiological measurements to complex molecular analyses.

Telomere Analysis: One common approach focuses on the length of telomeres, the protective caps found at the ends of chromosomes. Telomeres shorten with each cell division, acting as a "mitotic clock" that limits the number of times a cell can divide before it senesces or dies. Abnormally short telomeres are associated with accelerated cellular aging and an increased risk of various age-related diseases, including certain cancers and cardiovascular conditions. While specialized tests like flow-FISH are used in clinical settings to diagnose genetic diseases linked to telomere dysfunction, the qPCR telomere tests marketed directly to consumers are generally viewed with skepticism by researchers due to their variable reliability and lack of robust correlation with healthy aging outcomes.

DNA Methylation (Epigenetic Clocks): A more sophisticated and increasingly prominent method involves measuring DNA methylation, a physiological process where methyl groups are added to DNA molecules, chemically altering gene expression without changing the underlying DNA sequence. The rate and pattern of DNA methylation change predictably with age, making it a powerful biomarker for biological age. Scientists have developed "epigenetic clocks," such as the Horvath Clock and DunedinPACE, which analyze specific methylation sites across the genome to estimate biological age and even the pace of aging. These clocks were initially developed as research tools to study the effects of lifestyle, environment, and interventions on aging. While they offer promising insights into an individual’s aging trajectory, their commercial application for direct consumer use still faces questions regarding standardization, interpretation, and clinical utility. A key limitation is that most current DNA methylation tests from blood samples only reflect the methylation status of blood cells, not necessarily every organ or tissue, as different organs can age at different rates. These tests typically cost around $300.

Beyond these molecular markers, many conventional medical tests also track biomarkers of aging. Regular doctor visits often include assessments of blood pressure, cholesterol levels, and blood glucose, all of which are critical predictors of future cardiovascular disease risk and overall health. Monitoring these established clinical biomarkers is a proactive approach to wellness, enabling early intervention rather than waiting for overt disease symptoms to manifest.

The Purpose of Biomarker Testing: Motivation and Objective Data

The allure of biomarker testing lies in its potential to offer a tangible, data-driven assessment of one’s health status. For many, it serves as a powerful motivator. Discovering that one’s biological age is significantly older than their chronological age can provide the impetus needed to adopt healthier habits, such as consistent strength training, improved nutrition, or stress management. Conversely, a younger biological age can reinforce positive lifestyle choices.

Furthermore, biomarkers provide objective data, allowing individuals and their healthcare providers to quantitatively track and evaluate the impact of various health-related interventions. By continuously monitoring metrics like blood pressure, one might observe that regular exercise consistently lowers readings, while a late-afternoon energy drink has the opposite effect. This feedback loop can be instrumental in personalizing health strategies and fostering a sense of control over one’s well-being.

Accessible Insights: Five Free Biomarker Tests

While advanced bio age tests can be costly, a wealth of scientifically validated, underappreciated tests can provide significant insights into one’s biological age and overall fitness—for free. These practical assessments were frequently used by researchers to evaluate aging rates before the advent of high-tech molecular diagnostics.

1. The Sitting-Rising Test (SRT): This test assesses both strength and balance, critical indicators of longevity. Studies, including a 12-year study of 4,200 adults, have linked low SRT scores to a higher risk of cardiovascular disease mortality. To perform, lower yourself to the floor into a crisscross leg position, then stand back up, keeping legs in the same position. Start with 10 points; deduct one point for each body part used for leverage (hand, shin, knee) and half a point for unsteadiness. A low score indicates potential areas for improvement in balance, coordination, muscle strength, and mobility.

2. Grip Strength Test: Grip strength serves as a robust proxy for overall muscular fitness. Weak hand muscles often correlate with generalized body weakness. Research has shown that poor grip strength can predict future muscle weakness and is associated with reduced mobility, increased risk of falls, cardiovascular disease, and premature mortality. In one study, grip strength proved a better indicator of longevity than blood pressure. To test, squeeze a standard tennis ball as hard and long as possible. 15-30 seconds is average, 90 seconds or more is excellent. While a simple ball squeeze provides a rough estimate, a hand-held dynamometer offers a more precise measurement and is available at many physical therapy clinics or gyms.

3. One-Foot Stand Test: The ability to balance on one foot for an extended period is a crucial indicator of neurological function, inner ear health, skeletal muscle coordination, and vision. It significantly reduces the risk of falls, a leading cause of injury-related death in older adults. Conditions like diabetes, heart disease, and cancer can impair balance, making this test a valuable early warning sign for eroding health. To perform, stand near a wall for safety, hands on hips, eyes open. Lift one leg and time how long you can hold the position. Repeat for the other leg. Compare your times to age-matched averages; for example, a 50-year-old male averages 42 seconds, while a female averages 48 seconds.

4. Fatigability (How You Feel): Persistent, unexplained exhaustion, distinct from transient tiredness, can be an early indicator of underlying health issues. This "fatigue" involves mental dullness and emotional exhaustion, signaling that "something’s off." Beyond common culprits like sleep deprivation or chronic stress, persistent fatigue can point to developing health problems such as anemia, obesity, depression, cancer, or diabetes. For individuals aged 60 or older, fatiguability—the perceived effort or weariness after an activity—is a predictor of longevity. Higher fatiguability scores correlate with an increased risk of future death and declines in physical fitness. The Pittsburgh Fatigability Scale, rating perceived fatigue (0-5) after various activities (e.g., 30 minutes of leisurely walking, 1 hour of brisk walking), can be used. A total score below 15 is considered good, 15-24 a warning sign, and 25 or above severe, warranting professional medical consultation.

5. Body Composition: The ratio of lean mass (muscle, bone, water) to fat mass is a critical determinant of health and longevity. Both excessive and insufficient body fat can negatively impact health. Too much fat increases the risk of heart disease, high blood pressure, cancer, type 2 diabetes, and inflammation. Conversely, insufficient muscle mass (sarcopenia) raises risks for heart disease, high blood pressure, cancer, stroke, insulin resistance, faster cellular aging, depression, and falls. While gold-standard methods like DEXA scans are costly, a simple tape measure can provide a comparably accurate estimate. Measurements of waist, hip, and neck circumference, along with age, sex, height, and weight, can be plugged into free online calculators to estimate body fat percentage.

Doctor-Approved Biomarker Tests: Essential for Preventative Care

Beyond the free self-assessments, several doctor-approved tests, often covered by insurance as part of routine preventative care, offer deeper insights into biological aging and disease risk.

1. Comprehensive Blood Panel: Annual blood work is a cornerstone of preventative medicine. Monitoring key blood markers can detect trends toward type 2 diabetes or heart disease, both leading causes of premature mortality. Many of these markers are highly responsive to lifestyle changes (within 6-12 weeks), making them excellent tools for tracking the effectiveness of diet, exercise, or medication. Essential markers include:

   • Total Cholesterol, LDL, HDL, Triglycerides: Indicators of cardiovascular health and risk of atherosclerosis. Optimal ranges are well-defined (e.g., total cholesterol < 200 mg/dL, LDL < 100 mg/dL).
   • Apolipoprotein B (Apo B) and Lipoprotein (a): More precise markers for cardiovascular risk, as they reflect the number of atherogenic particles.
   • C-reactive Protein (CRP): A marker of systemic inflammation, often associated with increased risk of heart disease and other chronic conditions. Optimal range < 2.0 mg/L.
   • Fasting Glucose and Hemoglobin A1C: Crucial for assessing blood sugar regulation and diabetes risk. Fasting glucose < 100 mg/dL and A1C < 5.7% are considered optimal.
     Consulting a healthcare professional to interpret these numbers and calculate a cardiovascular disease risk score is paramount.

2. Bone Density (DEXA Scan): Strong bones are a hallmark of healthy aging and a common feature among "super-agers" living past 90. Bones are metabolically active organs that secrete hormones like osteocalcin, which may play roles in muscle function, brain health, and metabolism. Declining osteocalcin levels with bone loss are theorized to contribute to age-related health problems. Critically, loss of bone density (osteoporosis) leads to fractures, which significantly increase mortality risk for up to a decade post-break. DEXA scans measure bone mineral density, providing a T-score that compares an individual’s density to that of a healthy young adult. A T-score between +1.0 and -1.0 is normal. Regular monitoring is especially important for individuals in high-risk categories, such as post-menopausal women, those with a family history of osteoporosis, or individuals on certain medications. Insurance typically covers DEXA scans for those over 65 or with documented risk factors.

Commercial Bio Age Tests: High-Tech but with Caveats

For those with the financial means, the commercial market offers several high-tech tests promising deep insights into the body’s aging process. However, it’s crucial to approach these with a critical perspective, understanding their limitations.

Caveats to Commercial Tests:

• Variability: Biological age can fluctuate due to stress, recovery, or illness, and different organs may age at different rates. A single test result is a snapshot, not a definitive declaration.
• Accuracy and Reliability: Many commercial tests lack the robust scientific validation and longitudinal studies needed to definitively prove their accuracy in reflecting individual health outcomes or the effectiveness of interventions.
• Commercial Exploitation: Beware of companies that pair test results with a hard sell for proprietary, expensive supplement protocols. Always discuss results with a trusted health professional.

1. DNA Methylation Clocks: As discussed, these tests (e.g., Horvath Clock, DunedinPACE) analyze methylation patterns to estimate biological age and aging pace. While powerful research tools, their utility for the average consumer is still evolving. They typically cost around $300. A key point is that blood-based methylation tests only reflect the methylation status of blood cells, not necessarily a holistic view of every organ’s biological age. They are not a substitute for a comprehensive annual wellness checkup.

2. Telomere Analysis (qPCR): These tests measure the average length of telomeres, the protective caps on chromosomes. While telomere shortening is linked to aging, the qPCR tests marketed to the public for about $100 are not the same as the more accurate flow-FISH tests used in clinical research. Their reliability in predicting aging or disease risk in healthy individuals is highly debated, making them more a curiosity than a foundation for health decisions.

3. VO2 Max Testing: For years, VO2 max—the maximum amount of oxygen the body can use during exercise—was primarily of interest to elite athletes. However, it is increasingly recognized as a potent biomarker for overall health, cardiovascular fitness, and longevity. Individuals with a high VO2 max are not only fitter but also exhibit a lower risk of heart disease, diabetes, cancer, and stroke. A significant observational study following Danish men for 46 years found that those with above-average VO2 max in middle age lived an average of five years longer. Each unit increase in VO2 max correlated with a 45-day increase in longevity, suggesting it may predict all-cause mortality more accurately than traditional risk factors like high cholesterol.

   VO2 max naturally declines by about 10% per decade after age 30 due to age-related changes in the heart, lungs, and muscles. Reliable measurement typically involves lab-based testing (wearing a metabolic mask during exhaustive exercise), costing around $150, which also provides data on anaerobic threshold and fat/carb burning zones. More accessible, though less accurate, alternatives include:

   • The 1-mile walk test: Walking one mile on a flat surface while wearing a heart rate monitor, then plugging heart rate and time into a formula or online calculator.
   • Smartwatch estimates: Many smartwatches estimate VO2 max, useful for tracking trends but less precise for a definitive current health status.
   • The Cooper 12-minute run test: Running as far as possible on a flat surface in 12 minutes, then using a formula or online calculator to estimate VO2 max. This method has a high correlation (90%) with lab-based measurements.

Changing Your Biological Age: From Data to Action

The information gleaned from biomarker aging tests should be viewed as precisely that: information. It is not a moral judgment nor a permanent verdict. Biological age is dynamic and can be influenced by conscious effort. The critical step is to translate this data into actionable lifestyle changes.

Most individuals make two common mistakes when pursuing longevity-related lifestyle changes:

1. Ignoring Evergreen, High-Impact Strategies: The most profound and sustainable improvements in biological age and overall health stem from consistent adherence to fundamental, often "boring," health practices. These include:

   • Regular physical activity (aerobic and strength training)
   • A balanced, nutrient-dense diet rich in whole foods, fruits, and vegetables
   • Adequate, high-quality sleep
   • Effective stress management techniques
   • Maintaining a healthy weight and body composition
   • Avoiding smoking and excessive alcohol consumption
   • Cultivating strong social connections
   • Engaging in lifelong learning and cognitive challenges

   Thousands of studies consistently demonstrate that individuals who prioritize these strategies not only live longer but also experience a higher quality of life, with reduced disability and pain in their later years. The temptation to seek quick fixes or trendy supplements often overshadows the commitment required for these foundational changes. Behavior change is challenging, which is why professional guidance from certified health coaches trained in the science of habit formation can be invaluable.

2. Not Translating Data into Action: The collection of biomarker data, in isolation, does not extend life. Data serves as a baseline, a mirror reflecting current physiological realities. If you assess your biological age, note areas of concern, and then fail to implement corresponding behavioral changes, the exercise is largely futile. It’s akin to observing spinach in your teeth but choosing not to remove it. Biomarker testing’s value lies in its ability to inform, motivate, and help track progress as individuals embark on a journey towards a longer, healthier life. It should be a tool for continuous improvement, not a one-off diagnostic.

In conclusion, while the pursuit of biological age reversal, exemplified by figures like Bryan Johnson, captures public imagination, the true utility of bio age testing lies in its capacity to provide objective, actionable insights. Whether through free, accessible self-assessments, routine doctor-approved tests, or advanced commercial diagnostics, the ultimate goal remains the same: to empower individuals to make informed lifestyle choices that optimize their health span and longevity, focusing on scientifically proven strategies that move beyond mere data collection to tangible, sustained behavioral change.