Are Whoop & Gamin’s VO2 Max Estimates Accurate?
By Coach Johnny B (Ms, CFL3, LMT)
A common question I get from people who come in for a VO2 Max test at ASR is, “Do you think my Garmin, Whoop, Apple Watch, Coros, Oura, or Ultrahuman is accurate?”
For years, I would say, “Let’s see,” and then let the test speak for itself.
About a year ago, I decided to invest in a significantly better VO2 max testing device, made by a company called KORR Medical so we could start utilizing it to conduct tests for cardiologists and pulmonologists, and also help individuals with cardiac rehabilitation.
At that time, I also decided to start tracking every single person’s wearable device (if they had one) and predicted VO2 max versus what it actually was. Additionally, I started tracking their wearable heart rate metrics during the test to compare them with those from a hardwired chest strap.
After 1 year and 121 tests the results of my data analysis and my conclusions are as follows:
VO2
- Gamin: Average of 5.2 lower than actual VO2 max (58 wearers)
- Whoop: Average of 4.31 higher than actual VO2 max (33 wearers)
- Apple Watch: Average of 4.9 lower than actual VO2 max (20 wearers)
- Oura: Average of 5.8 points lower than actual (5 wearers, not enough data)
- Coros: Average of 5.8 points lower than actual (3 wearers, not enough data)
- Ultrahuman: Average of 17.55 higher than actual (2 wears, not enough data)
Heart Rate:
(I, unfortunately, could not get as much data on this as some of the devices recorded inaccurately due to severe lag, meaning they didn’t register the exercise until hours later, so not all the devices got graded here)
- Garmin Wrist Sensors: Average deviation of 5 beats per minute, either high or low, during running and cycling
- Whoop was, on average, 3.8 beats per minute lower to 7 beats per minute higher during running and cycling, depending on the intensity (so at low intensity, it was on average 3.8 BPM lower; at high intensity, it was 7 BPM higher)
- The Apple Watch was, on average, 27 beats per minute off the actual heart rate in either direction.
My Conclusions Based On This Data
- If you want to know your VO2 Max, you should have it measured by someone using lab-quality equipment that has been reviewed for accuracy (note: the company PNOE is not accurate and should not be trusted). If you’re unsure why VO2 max is important, consider reading this article on the topic. For health, the American Heart Association states that VO2 Max is a better predictor of mortality risk due to heart disease than traditional factors, such as cholesterol levels. For performance, we can predict your marathon finish time with an accuracy of 1:00 or less (i.e., if you don’t have a VO2 max of 60 or greater, you cannot run a sub-3-hour marathon).
- If you care about accurately measuring your heart rate during workouts, you must use a chest strap; otherwise, you may not be getting the results you think you are. Zone 2 is all the rage these days due to Peter Attia’s book, Outlive. The reality is that our wrist-based wearables are so poorly suited for measuring heart rate during a workout that they are usually off by a significant zone. Being off by a zone means that you could be in Zone 3 when you thought you were in Zone 2, which means you won’t receive any of the benefits of Zone 2 cardio.
- Our wrist-based wearables are entertainment devices, and no one should make any health-based decisions or fitness judgments solely based on them. The Apple Watch can undoubtedly tell you if you are in AFib (and that’s great!), but it cannot tell you if you are having a heart attack or if your heart is healthy. The Whoop, Garmin, etc., are good at measuring heart rate when you are perfectly still but not great when you move. Unfortunately, both devices utilize heart rate for features such as HRV, Sleep Score, Strain, and Body Battery, among others. Therefore, if that is inaccurate, everything else is likely to be incorrect as well. This fact makes it critical to compare this data with real, lab-based tests.
- If you monitor your heart rate for health or performance reasons, it is essential to wear a chest strap for accurate heart rate monitoring.
