HRV and recovery: a signal, not a green light
Wearable biometrics can enrich a coaching discussion. They do not replace symptoms, history or clinical judgment.
Look for a personal trend
Heart-rate variability changes with measurement conditions, timing and individual physiology. A single value is difficult to interpret without a consistent method and a baseline. The same principle applies to resting heart rate and wearable recovery scores.
What the evidence actually suggests
A systematic review of eight studies found that HRV-guided approaches improved some submaximal physiological measures, while average advantages for endurance performance and peak oxygen uptake were small and not statistically significant. The lesson is to use HRV as context, not sell it as an automatic performance optimizer.
Combine signals and report uncertainty
Sleep, subjective fatigue, soreness, stress and the last training sessions may alter the interpretation. JMM should preserve unknown data as unknown. If concerning symptoms are reported, biometrics do not overrule a safety hold.
Evidence and limitations
External research references. They do not validate JMM clinically or establish product efficacy.