Body Age / Fitness Age Calculator
See How Young Your Body Really Is
The Garmin Venu 3S smartwatch measures VO₂ max, sleep, heart rate, and stress to estimate your fitness age and overall vitality—helping you track true wellness over time.
Shop Garmin Venu 3SAbout the Body Age / Fitness Age Calculator
The Body Age / Fitness Age Calculator estimates how your current fitness markers compare to typical values across ages, giving an educational Fitness Age versus your chronological age. It combines BMI and waist-to-height ratio (WHtR) for body composition with resting heart rate (RHR), weekly activity (MET-minutes), and optional VO₂ max for cardiorespiratory fitness.
Results include a clear breakdown of each factor so you can see what’s driving your Fitness Age. Lower RHR, regular moderate-to-vigorous activity (e.g., 150 min/wk moderate or 75 min/wk vigorous), and favorable WHtR (≈≤0.5) generally correspond to a “younger” fitness profile. If you enter a lab or wearable-derived VO₂ max, the model weights that heavily for the cardio component.
FAQ
- What is Fitness Age?
An educational estimate of how your fitness markers (BMI, WHtR, RHR, activity, optional VO₂ max) compare to typical values at different ages. - How accurate is a Fitness Age calculator?
It’s a simplified model for personal education — useful for trends and comparisons, not a medical or performance diagnosis. - Which inputs matter most?
Body composition (BMI, WHtR) and cardiorespiratory fitness (RHR, activity). If you enter VO₂ max, it has a strong influence on the cardio component. - How do you use VO₂ max in the calculation?
Your VO₂ max is compared with an age/sex expectation; higher values typically lower your Fitness Age, lower values increase it. - What is a good Fitness Age?
Being near or below your actual age suggests a relatively favorable profile. Focus on trends over time rather than a single number. - How can I lower my Fitness Age?
Build consistent aerobic + strength training, increase daily steps, aim for ~150 min/wk moderate or 75 min/wk vigorous activity, improve sleep and nutrition, and reduce central adiposity (lower WHtR). - What resting heart rate is considered good?
Many healthy adults are roughly 60–80 bpm at rest; trained individuals can be lower. RHR trends matter more than one reading. - What is a healthy waist-to-height ratio (WHtR)?
A commonly cited threshold is ≤0.5 for many adults; higher values indicate more central adiposity. - Does high muscle mass affect results?
Yes — muscular people can have a higher BMI despite low fat. That’s why WHtR and cardio markers (RHR, VO₂ max, activity) are also included. - Can wearables estimate VO₂ max accurately?
Many devices provide reasonable estimates from heart-rate dynamics, but lab testing is typically more precise.
Disclaimer
For educational purposes only. Not medical or training advice.
References
- World Health Organization. Guidelines on Physical Activity and Sedentary Behaviour.
- American College of Sports Medicine (ACSM). ACSM’s Guidelines for Exercise Testing and Prescription.
- Ashwell M, Gibson S. Waist-to-height ratio as a screening tool for cardiometabolic risk: systematic review & meta-analysis.
- Piercy KL et al. Physical Activity Guidelines for Americans — key updates and recommendations.
- Wisløff U, Nes BM et al. Cardiorespiratory fitness (“fitness age”) and risk across the lifespan.
- Seppälä-Lindroos A et al. Resting heart rate, adiposity and cardiometabolic risk relationships.