Whoop vs Oura: We test Both!

Whoop and Oura are both popular wearables — but which is better, and which is right for you? Frank and I have been wearing both side by side for months, and here we track how the two stack up in the FasCat Test. Also, we look at two recent academic studies on the accuracy of various wearables.  

Whoop vs Oura - The FasCat Test

For a few weeks I tracked the following for each wearable:

• HRV
• resting heart rate
• sleep
• sleep phases
• each brand’s so-called Recovery and Readiness scores

It's interesting how they align on some things and are miles apart on others.

I found testing wearables to be similar to testing power meters - how do you know which one to believe? All you can do is look for trends and use common sense. The academic studies below had the benefit of both big groups for testing and testing against ECG straps. I just used the two devices concurrently. 

I found that Whoop and Oura tracked roughly in line with each other for HRV, in that they’d rise and fall together. The number was never the same, but the were usually within two or three points of each other. So I found that to be reassuring. The Whoop read a little higher on average, which was Frank's experience, too.

For resting heart rate, the two devices were spot on for average heart rate overnight. It was either an identical number, or off by a single BPM. I wish I could find two power meters that would agree this closely! Suffice it to say, I found this super reassuring.

For sleep… that’s where they’d lose each other, particularly for the type of sleep. The total time of sleep was close, usually within 10 to 20 minutes of each other. Here, my Oura read higher.

For the so-called restorative sleep - that’s REM plus Deep Sleep - that was all over the map. This would vary between four minutes and nearly two hours’ variance - and it would swing both ways. My conclusion here: a ring or a wristband can’t tell what stage of sleep you’re in. Neat-looking graphs and all, but I don’t find the data believable.

Academic Studies

Two recent studies looked at the accuracy of wearables for sleep, heart rate, and heart rate variability (HRV).

One was done by Dr. Dean Miller, a senior postdoctoral research fellow at the ​​Central Queensland University in Australia. That was reviewed by Dr, Lian Allen, a PhD and Senior Research Scientist at Lululemon. This study used PSG and ECG devices to test against Apple, Garmin, Polar, Oura, Whoop, and Somfit wearables. 

For total sleep, all the devices were found be generally reliable. For type of sleep, the study said there were ‘pronounced differences between devices’. As in, the alignment was like 50% to the lab equipment. In others words, none were good at all at detecting levels of sleep.

For heart rate and HRV, it got a bit murkier. The Whoop, Oura and Apple Watch all did well, while the Garmin stunk it up - at under 50% correlation to the lab equipment. We should note that the equipment tested was not the latest and greatest. The Whoop was gen 3, the Oura gen 2, and the Garmin was a Forerunner 245 Music! So pretty off the back. And the study acknowledges that.

You can read the full study here, and Dr. Allen's more easily readable review of it here. 

The second study was a collaborative effort done by researchers at West Virginia University, Boston University, and the Detroit Lions. It was reviewed by academics at the University of Adelaide and the Mayo Clinic. The title is a mouthful: "Assessing the Accuracy of Popular Commercial Technologies That Measure Resting Heart Rate and Heart Rate Variability."

This study tested five wearables: a Shimmer, a Polar strap, a Firstbeat strap, a Gen 2 Oura ring, and an iPhone 8. They ran into the same issue as they other study with the industry’s development outpacing the scientific study.

For measuring just heart rate, this study found that chest straps were the best, the camera on the iPhone was the worst. And the Oura was pretty darn close to the chest staps.

For HRV, they found a wide range. Here is an excerpt:

"Similar to previous studies, devices performed with varying degrees of veracity with ranging from 4 to 112%. The greatest degrees of confidence are extended to a wearable Polar ECG strap and OURA, as our data suggests they can most accurately report HRV.

ECG-based devices generally outperformed PPGs, although there were a couple of exceptions. The Oura smart ring (PPG) exhibited better accuracy than all cECGs except for the Polar and the Firstbeat, and the Firstbeat lacked in HRV accuracy."

You can do a deep dive into the full study here.

Bottom line

Development is coming thick and fast from Whoop, Oura, Garmin, and Apple, and the scientific studies are struggling to keep up. That said, Whoop and Oura both test reliably for heart rate, HRV, and total sleep time — in both our internal tests and the scientific tests.

So when deciding between Whoop and Oura, you have two good options, and the 'wearability' of each could be the deciding factor. Frank likes the feel of the Whoop better but likes the data from the Oura. I prefer the low-profile look of the Oura to the wristband of the Whoop, and the fact that its battery lasts longer.