A recent study of WHOOP by the Univesity of Arizona and published on PUBMED/Journal of Clinical Sleep Medicine, concludes that…
In healthy people, wearables can improve sleep quality and accurately measure sleep and cardiorespiratory variables.
Whilst that is superficially GOOD. Let’s dissect it a little
- The study did show that WHOOP’s heart rate and breathing algorithms were accurate to +/-1bpm at resting (sleep) levels. That’s good to know but I assume not spectacular compared to competitive products.
- The study also showed, to 95% accuracy, that using WHOOP did lead to an improvement in sleep quality as measured by PROMIS Sleep Disturbance – which is based on PATIENT RECORDED OUTCOMES.
- Surprisingly it also showed low errors of deviance from sleep stages measured during polysomnography. Although that does assume that the latter is correct.
Finally, I’m not sure if there was an equally-motivated control group who were given instructions in another format on how to increase sleep quality.
Must Read: Check out the latest WHOOP Review
https://the5krunner.com/2025/10/31/2026-whoop-5-0-mg-review-discount-accuracy-strain-recovery-athletes/
Last Updated on 21 January 2026 by the5krunner
My favourite kit and nutrition
- Injinji – Runners protect your toes. Avoid discomfort and minor injury. Run more. Run faster. I use them.
- Garmin 90-degree charging adapter — A small keyring adapter you can use anywhere. Essential when away. I use one.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session. I use one.
- Ravemen FR300 — Front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters. I use one.
- Body Glide – The blue anti-chafe stick that all swimmers and many runners use. I use it.
- Maurten — The race nutrition trusted by elite athletes. Gels and drink mixes engineered to be easy on the stomach. I use them.
- Garmin Varia RTL515 — A radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Wahoo. I use this model.
- Favero Assioma Pro RS2 — The power-meter pedals most serious cyclists choose. Accurate, easy to move between bikes. I use this model.
- Garmin Forerunner 970 — A serious choice for a pro-grade triathlon watch. I use this.
- Polar H10 — My daily driver for accurate, waking HRV readings.
- Wahoo ELEMNT Roam 3 — The bike computer that has the feature Garmin lacks: usability. I use mine on most rides.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID