True Age
What it is: Your biological age based on four biomarkers that predict all-cause mortality risk. True Age tells you what age your body is actually functioning at, independent of the years you've been alive.
The foundation of longevity: True Age measures your body's biomarkers across cardiovascular and metabolic health. True Age components are the scientifically validated foundation of longevity on which everything else is built. Without a strong foundation (good VO2max, resting heart rate, HRV, and muscle mass), advanced optimization strategies won't deliver lasting results.
The four biomarkers:
VO2max - cardiovascular fitness
Resting heart rate - cardiovascular efficiency
Heart rate variability - stress resilience and autonomic health
Lean body mass index - muscle mass and metabolic health
Data requirements:
Lookback window: Past 4 complete weeks (Monday to Sunday)
Updates: Every Monday with data from the previous 4 full weeks
RHR and HRV: Need 4+ days with readings across the 4 weeks
VO2max and LBMI: Need at least 1 reading across the 4 weeks
Confidence levels: High, Medium, or Low based on data completeness and recency for each biomarker
What it means:
True Age < chronological age = your body is aging more slowly than average
True Age = chronological age = your biomarkers match your age and sex
True Age > chronological age = your body is aging faster than average (opportunity to act)
Pace of Aging
What it is: Whether you're aging faster or slower than the clock. Pace of Aging is a multiplier that shows your recent rate of biological aging.
How it works: reThrive calculates a stable trend using linear regression over at least 4 weeks of True Age measurements. This eliminates noise from week-to-week variations and gives you a reliable baseline.
Data requirements:
Minimum: 4 weeks of True Age measurements
Calculation window: Linear regression over up to 16 complete weeks of True Age data
Updates: Every Monday alongside True Age updates
What it means:
Above 1.0x = True Age increasing faster than chronological age (time to act)
1.0x = True Age increasing at the same rate as the clock
Between 0.0 and 1.0x = True Age is increasing slower than your chronological age (good)
Negative = rejuvenating, your True Age is decreasing (very good)
Thrive Levers
What they are: Six specific actions organized into three pillars that directly impact your biomarkers and True Age.
The six levers:
Movement
Non exercise activity time / Daily steps
Light activity (HR Zone 1-3 time)
Performance
Vigorous activity (HR Zone 4-5 time)
Strength training duration
Recovery
Sleep duration
Sleep consistency
How they work: Each lever impacts one or more of your four biomarkers. reThrive analyzes which biomarkers need the most improvement and shows you which levers to pull for maximum impact.
Data requirements summary
Metric | Minimum data | Lookback window | When available |
True Age | 4+ days RHR/HRV, 1+ reading VO2max/LBMI | 4 complete weeks | Immediately if you have historical data, or after 1 week |
Pace of Aging | 4+ weeks of True Age measurements | Up to 16 complete weeks | Immediately if you have historical data, or after 4 weeks |
Thrive Levers | True Age available | N/A | Coming soon |