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What your wearable's numbers mean, why they move, and what to do when they look wrong. Every claim links to its source.

9 Oct 2026Does Apple Watch have a recovery score?Since September 2026, yes on two models: Readiness, 0-10. Older watches have Vitals, Training Load and Sleep Score but no single daily score.
7 Oct 2026Which Fitbit and Pixel devices track which metricsWhich Fitbit and Pixel Watch models track Readiness, Cardio Load, Active Zone Minutes, HRV, SpO2 and skin temperature, from Google's own help pages.
3 Oct 2026Google Health API for self-hosters: scopes and user capWhat a self-hosted app needs from the Google Health API: the OAuth scopes Pulse asks for, the 100-user cap on unverified apps, and the Cloud project steps.
29 Sept 2026WHOOP membership cost: One, Peak and Life in 2026WHOOP One, Peak and Life cost $199, $239 and $359 a year in the US, and from ₹21,990 in India, as of October 2026. What each includes and what is unconfirmed.
27 Sept 2026Pixel Watch readiness or sleep score missing? ChecksWhy a Pixel Watch shows no readiness or sleep score: the 7-night baseline, 3-hour sleep minimum, missing sleep stages, fit and sync, in order of likelihood.
25 Sept 2026Google Health vs Health Connect vs Apple HealthWhat the Google Health app, Android's Health Connect, Apple Health and the Google Health API each do, how they sync, and what to check when data goes missing.
19 Sept 2026Why WHOOP, Garmin and Oura scores disagreeWHOOP Recovery, Garmin Body Battery and Oura Readiness can tell you different things on the same morning. Why, and how to read them side by side.
17 Sept 2026Fitness Age vs Pulse Age vs WHOOP AgeGarmin Fitness Age, WHOOP Age and Pulse Age all put a number of years on your body, but they measure different things. How each works and how far to trust it.
15 Sept 2026Open-source WHOOP alternatives: what exists in 2026A survey of open-source and source-available projects that stand in for a WHOOP subscription: licences, supported devices and activity, checked October 2026.
11 Sept 2026Oura Readiness explained, and how Recovery differsThe nine contributors behind Oura's Readiness score, what each one measures, why it dips, and how it differs from a morning Recovery percentage.
7 Sept 2026WHOOP alternatives with no subscription (Oct 2026)WHOOP alternatives with no subscription, dated and priced: Fitbit Air, Garmin Cirqa, Polar Loop, Amazfit Helio Strap, Apple Watch apps and Pulse.
6 Sept 2026Garmin Training Status 'Unproductive': what to doUnproductive means your fitness estimate is falling despite training, and Garmin says that is not always overtraining. What feeds it and what to check first.
2 Sept 2026Fitbit dashboard on your own server: Grafana or Pulsefitbit-grafana draws your raw Fitbit data in Grafana. Pulse computes scores like Recovery and Strain. What each needs, does and leaves out.
29 Aug 2026Is Google Health Premium worth it?What stays free in the Google Health app and what moves behind Premium: scores, Target Load, sleep insights and the coach, with prices as of October 2026.
27 Aug 2026WHOOP Strength Trainer vs heart-rate-only strainWhy heart rate alone underrates weightlifting, how WHOOP Strength Trainer adds muscular load, and what that means for any strain score built on heart rate.
25 Aug 2026Garmin VO2 max accuracy: watch vs labWhat peer-reviewed studies found when Garmin's VO2 max was compared with lab gas analysis: errors of roughly 3 to 10%, and worse for highly trained runners.
19 Aug 2026Fitbit VO2 max and Cardio Fitness: how accurate?What Fitbit's Cardio Fitness Score is built from, what the one lab validation found showed, and how to read the number you get.
17 Aug 2026How to export your Fitbit data in 2026Three ways to get your Fitbit data out: Google Takeout, the Fitbit Data Export page and the Google Health API, with what each gives you and its limits.
15 Aug 2026Garmin stress level always high? What it measuresGarmin's stress score is a 0-100 reading of heart rate variability while you are still, not a measure of feelings. Bands, why it runs high, and what to check.
11 Aug 2026WHOOP Journal: which behaviours move your recoveryHow WHOOP Journal turns yes/no entries into Behavior Insights, how many entries it needs, which behaviours to log first, and why the results are correlations.
7 Aug 2026Active Zone Minutes: what your Fitbit really countsHow Fitbit's Active Zone Minutes are earned, how they differ from Cardio Load and active minutes, and why a number can look off after a workout.
6 Aug 2026Garmin sleep score explained, and a published alternativeGarmin's 0-100 sleep score blends duration, quality and HRV-based stress, with unpublished weights. The bands, a typical score, and a published alternative.
2 Aug 2026Amazfit BioCharge vs Garmin Body BatteryBoth are 0-100 energy gauges. What Amazfit and Garmin actually publish about each, why BioCharge is now HybridCharge, and what a score can't tell you.
29 Jul 2026WHOOP Healthspan and Pace of Aging, explainedWHOOP Age is a six-month estimate from nine habits and vitals. Pace of Aging is the 30-day speedometer. What goes in, what it means, and what it can't tell you.
27 Jul 2026Fitbit resting heart rate high? Likely causesA higher Fitbit resting heart rate usually has an ordinary cause: alcohol, caffeine, poor sleep, illness, a hard week. How to tell, and when to see a doctor.
25 Jul 2026How to improve your sleep regularityWhat moves your Sleep Regularity Index, with worked examples of late weekends and naps, and the research on why a regular schedule matters.
20 Jul 2026Garmin Load Ratio and Acute Load: the ACWR linkHow Garmin's Acute Load and Load Ratio work, how they relate to the acute:chronic workload ratio (ACWR) from sports science, and why that idea is contested.
17 Jul 2026Does Fitbit Air have Body Battery? The closest matchNo. Body Battery is Garmin's metric. Here is what Google Health gives you instead, why it isn't the same, and how to get a running energy figure.
15 Jul 2026WHOOP sleep need and sleep performance, explainedHow WHOOP sets your nightly sleep need, what Sleep Performance scores, why 100% is hard to hit, and what is and isn't published about the weights.
11 Jul 2026Fitbit Target Load too high or low? How it is setHow Google sets Target Load on free and Premium plans, why it can feel wrong, and what to do. Plus how a daily Strain Target built from Recovery works.
7 Jul 2026Garmin HRV Status unbalanced: what it meansUnbalanced means your seven-day HRV average has left your personal baseline range, high or low. What Garmin says it means and what to check before worrying.
6 Jul 2026Fitbit Resilience replaced the stress score. Now what?Google Health swapped the 0-100 Stress Management Score for Resilience on 19 May 2026. What Google documents, what it doesn't, and how to read a Low day.
2 Jul 2026Fitbit sleep score: the six parts and what is goodGoogle lists six parts of the sleep score and four bands. What each part rewards, what counts as good, and what the help page leaves unsaid.
28 Jun 2026What is a good Body Battery? Garmin's bands explainedGarmin's four Body Battery bands, what counts as good in the morning and evening, why yours may sit low, and what the manual says does and doesn't move it.
26 Jun 2026What a WHOOP Recovery score actually measuresWHOOP Recovery is a 0-100% morning score from overnight HRV, resting heart rate, respiratory rate and sleep. What it can tell you, what WHOOP does not publish.
24 Jun 2026Fitbit Daily Readiness explained, and how Recovery differsWhat Daily Readiness is built from, what its bands mean, what Google doesn't publish, and how a 0-100% Recovery with published weights differs.
19 Jun 2026What is Amazfit PAI? Points, target and daily strainPAI is a weekly heart-rate score from Norwegian research: reach 100 over any rolling seven days. How it works and how it differs from a daily strain score.
16 Jun 2026HRV 0 or "not tracked" on Fitbit Air? What to checkHRV showing 0 or blank on a Fitbit Air usually means too little sleep, unstaged sleep or a loose fit. What Google says, what forums report, what to do.
14 Jun 2026Garmin Training Readiness always low: causesWhy Garmin Training Readiness sits at Low or Poor: the six inputs Garmin lists, which ones usually hold it down, and what to check first.
10 Jun 2026WHOOP Strain explained: scale, levels, what is goodWHOOP Strain is a 0-21 score of a whole day's cardiovascular load. What the bands mean, why it is logarithmic, and how to get a similar number from a Fitbit.
6 Jun 2026Cardio Load vs Strain: what the numbers meanFitbit's Cardio Load is an open-ended daily total with no published scale; Strain is a capped 0-21 score. What each measures and why they don't convert.
5 Jun 2026What is a good HRV by age? Your baseline matters moreReal RMSSD and SDNN averages by age decade from a study of 1,906 healthy adults, why wearable HRV differs from lab values, and how to judge your own.
1 Jun 2026Fitbit readiness always low? Check these 6 thingsA low or stuck Daily Readiness score usually traces back to sleep length, a raised resting heart rate, a short baseline or missing HRV. Six checks, in order.