Enter your VO2 Max, age, and sex to instantly see your ACSM fitness category — from Very Poor to Superior — and how you rank against your peers.
Values below are approximate ACSM thresholds in ml/kg/min. Age ranges shown: 20–29, 40–49, 60+.
| Category | Men 20s | Women 20s | Men 40s | Women 40s | Men 60+ | Women 60+ |
|---|---|---|---|---|---|---|
| Very Poor | <37 | <29 | <33 | <24 | <22 | <18 |
| Poor | 37–43 | 29–35 | 33–38 | 24–29 | 22–27 | 18–22 |
| Fair | 44–50 | 36–41 | 39–45 | 30–35 | 28–34 | 23–28 |
| Good | 51–56 | 42–47 | 46–51 | 36–40 | 35–40 | 29–33 |
| Excellent | 57–62 | 48–52 | 52–57 | 41–45 | 41–46 | 34–38 |
| Superior | ≥63 | ≥53 | ≥58 | ≥46 | ≥47 | ≥39 |
Source: ACSM's Guidelines for Exercise Testing and Prescription. Values are approximate population averages.
VO2 Max (maximal oxygen uptake) is the maximum rate at which your body can consume oxygen during intense exercise, measured in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). It is widely considered the gold standard measure of aerobic fitness and cardiovascular health, and is strongly correlated with long-term longevity and reduced risk of chronic disease.
VO2 Max norms vary significantly by age and sex. For men in their 30s, a VO2 Max of 48–53 ml/kg/min is considered Good by ACSM standards, while 54+ is Excellent. For women in the same age group, 39–44 is Good. VO2 Max naturally declines with age at roughly 1% per year after age 30, so fitness categories are always adjusted for age.
VO2 Max responds best to high-intensity interval training (HIIT) and consistent aerobic exercise. Studies show that interval sessions at 90–95% of max heart rate, combined with zone 2 base training (3–5 sessions per week), can raise VO2 Max by 5–15% over 8–12 weeks. Even walking regularly and gradually increasing intensity can meaningfully improve VO2 Max in previously sedentary individuals.
Wearables like Apple Watch, Garmin, and Polar estimate VO2 Max by analyzing the relationship between heart rate and pace (or power output) during outdoor runs or brisk walks. The algorithm compares how hard your heart works relative to your speed and uses models calibrated on lab-measured populations. Apple Watch specifically reports cardio fitness as an estimated VO2 Max and can estimate it from outdoor walks at a brisk pace.
HC Webhook sends your cardio fitness data — including estimated VO2 Max from Apple Watch — to any endpoint on a schedule, so your dashboards stay current.
