- HeartHRV: what heart rate variability tells youWhat HRV measures, why there is no general normal value, what lowers and raises it, and why Apple Watch, Oura and WHOOP show different numbers. With sources.
- HeartResting heart rate: what your pulse at rest tells youWhat resting heart rate is, why your own trend says more than a normal range, what raises and lowers it and how Apple Watch and others measure it. With sources.
- Body signalsBreathing rate during sleep: what your pace of breathing tells youHow many breaths per minute are normal in sleep, why your own range matters, what raises breathing rate, and how watches and rings estimate it. With sources.
- SleepSleep stages: deep, REM and core sleep explainedWhat deep, REM and core sleep are, how the stages change with age, what affects them and how accurately Apple Watch and others estimate them. With sources.
- FitnessVO₂max: how fit is your cardiovascular system?What VO₂max is, which values are good for your age and sex, how accurate the Apple Watch estimate is and what raises it. With a calculator and sources.
- ScoresReadiness score: what it is and how Salvor works out your daily formWhat a readiness score is, what goes into Salvor’s daily form (weights 30/45/15/10), how Oura and WHOOP approach it and what the research says. With sources.