Metric organizes cardio-related signals such as estimated VO₂ max, resting heart rate, heart-rate variability, activity, and workouts. Together they can add context to training and recovery. They do not reveal how strong your heart “really” is or rule out a cardiovascular problem.
Read the source and the trend
- Apple Watch cardio fitness is an estimate derived in supported circumstances, not a direct laboratory measurement.
- HRV varies with timing, posture, breathing, illness, alcohol, stress, and measurement method.
- Resting heart rate is more informative when sampling is consistent and viewed over time.
- A workout or activity gap can reflect device wear and permissions as well as behavior.
Do not use a score to clear symptoms
Unexpected chest discomfort, fainting, severe shortness of breath, or other urgent symptoms need appropriate medical attention regardless of what an app trend shows.
For ordinary review, compare longer windows, keep device use reasonably consistent, and inspect the source values behind a summary. A meaningful research association at the population level does not make an app estimate a prediction for one person.
Wellness and editorial boundary
Metric is a wellness product. Its scores, AI responses, nutrition analyses, and wearable-derived values are informational estimates, not diagnoses or medical advice. Results depend on the data available and may be incomplete or inaccurate. Review source data and speak with a qualified professional about health concerns.
- Metric Editorial TeamAuthor profile and review responsibilities
- Editorial policyHow Metric separates product education, evidence, and marketing
- Methodology and limitationsHow Metric describes calculations, coverage, and uncertainty
- Metric Apple Health dashboardMetric’s data overview
- Apple cardio fitness and VO₂ maxApple’s explanation of cardio-fitness estimation and availability
- Apple Watch heart-rate measurementsApple’s measurement guidance and limitations
- Apple Watch measurement accuracyFactors that can affect sensor readings
- Cardiorespiratory fitness and mortality meta-analysisPopulation-level research context, not an individual prediction