True Age is calculated using four biomarkers: VO2max, resting heart rate, heart rate variability, and lean body mass index. Here's what each one measures and why it matters.
What it measures: Your maximum oxygen uptake during exercise, measured in ml/kg/min.
Why it matters: VO2max is the strongest single predictor of cardiovascular mortality in population studies. It reflects your heart's ability to pump blood, your lungs' ability to oxygenate it, and your muscles' ability to use it.
Higher VO2max is associated with significantly lower all-cause mortality risk across all age groups. It's not just about athletic performance. It's about your body's fundamental capacity to sustain life.
How to improve it: Aerobic exercise, especially vigorous intensity training and high-intensity interval training (HIIT).
Research: Cooper Institute longitudinal studies, American Heart Association cardiovascular fitness guidelines.
What it measures: Your heart rate at rest, measured in beats per minute (bpm).
Why it matters: Resting heart rate is a marker of cardiovascular efficiency and autonomic nervous system health. A lower resting heart rate means your heart doesn't have to work as hard to pump blood through your body.
Lower resting heart rate indicates better cardiovascular adaptation and is associated with reduced mortality risk. Elite athletes whose cardiovascular systems are most efficient often have resting heart rates in the low 40s.
How to improve it: Regular aerobic exercise, stress management, adequate sleep, and reducing stimulant intake.
Research: NHANES epidemiological studies linking resting heart rate to cardiovascular outcomes.
What it measures: The variation in time between heartbeats, measured in milliseconds (ms).
Why it matters: HRV reflects your autonomic nervous system's ability to adapt to stress. Higher HRV indicates better cardiovascular health, stress resilience, and parasympathetic (rest-and-digest) activity.
Your heart rate should vary slightly from beat to beat in response to breathing, movement, and stress. A rigid, metronomic heartbeat is actually a bad sign. It means your nervous system isn't adapting well.
How to improve it: Quality sleep, stress management, moderate exercise (overtraining can lower HRV), and recovery practices.
Research: Population studies on parasympathetic activity decline with age and cardiovascular health.
What it measures: Your muscle mass relative to height, measured in kg/m².
Why it matters: Muscle mass naturally declines with age (sarcopenia) and is a strong predictor of functional independence, metabolic health, and longevity. More muscle means better glucose regulation, higher metabolic rate, and greater resilience to injury and illness.
LBMI is more meaningful than BMI because it distinguishes between fat mass and lean mass. Two people can have the same BMI but vastly different health profiles depending on their muscle mass.
How to improve it: Resistance training, adequate protein intake, and maintaining an active lifestyle.
Research: NHANES data on age-related sarcopenia and its impact on healthspan.
