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The wearable WHOOP tracker is a two-in-one device that uses both fitness and sleep data. The goal is to calculate overall recovery, which WHOOP defines as how prepared you are for activities in the day ahead based on your recent exercise, heart rate, and how well you slept the previous night.
The WHOOP has cultivated a major following within CrossFit and other workout communities. Many pro athletes also wear the tracker. That said, virtually anyone — even nonathletes — can benefit from the WHOOP’s comprehensive tracking system.
I recently had the pleasure of personally wearing and testing the WHOOP 3.0 for one week. Below you’ll find my breakdown of how the WHOOP operates, what it tracks, how it feels, and how well it works.
Due to shipping delays, I was unable to personally test the WHOOP 4.0, the latest version of the tracker that debuted in the fall of 2021. I’ve highlighted some of the key differences between the 3.0 and 4.0, but ultimately both iterations of the device are quite similar in terms of design, functionality, and operation.
The WHOOP is a wearable tracker with built-in photodiode sensors to monitor a wide range of metrics. The tracker is designed to be worn at all times. The more you wear it, the more accurate and consistent your personal data will be.
Metrics tracked by the WHOOP fall into three general categories: fitness, sleep, and recovery.
The WHOOP calculates Strain Score, a proprietary scoring system that measures how physically active you’ve been. This score changes throughout the day based on what you do and how hard you push yourself.
Strain Score is calculated based on your heart rate after different activities in relation to your maximum heart rate. The WHOOP is specifically tailored to each wearer based on heart activity, fitness level, and performance ability. Your score could significantly differ from another person’s, even if you’ve both completed the same physical activity.
Strain Score is measured on a scale of 0 to 21. Here’s a breakdown of how to interpret these numbers:
The WHOOP also calculates Day Strain, a rundown of all your activities within a 24-hour period and the amount of collective stress placed on your body. This feature is particularly useful if you’re gearing up for a race, competition, or other event that requires days or weeks of preparation.
You can also access the Strain Coach function at any time. This feature issues alerts when you should push harder to reach your goals, when you’ve reached your goal, or if you should take a breather due to too much strain.
The WHOOP is similar to other sleep trackers on the market in terms of the metrics it monitors. Each morning you’ll receive a detailed report of your sleep from the previous night. These reports cover the following:
The WHOOP also calculates Sleep Needed, which is based on your normal sleep patterns and your Day Strain score leading up to bedtime. Since you’ll need more rest after a day full of strenuous activity compared with a less active day, the amount of sleep you need fluctuates throughout the week.
The Sleep Needed metric also takes sleep debt into account. For example, if you needed eight hours of sleep last night and only slept for seven hours, then the hour of sleep debt you have accumulated will factor into the amount of sleep you need tonight.
Recovery pulls from a wide range of fitness and sleep tracking metrics. These include heart rate variability, or the amount of time between heartbeats during sleep. Another factor is resting heart rate, or the average number of heartbeats during the night. The latter is a weighted average, with heartbeats during SWS getting more weight because your heart rate slows during deep sleep. Other metrics used to calculate recovery include:
Measured on a 0% to 100% scale, recovery scores are interpreted using three color-coded categories:
|Green||67% or higher||Your body is ready for strain from physical activity.|
|Yellow||34% to 66%||While your body may be able to handle a high load of physical training, strain or poor sleep may hinder your efforts.|
|Red||33% or lower||Your body may need a day off or a low training load until you have had adequate time to recover.|
It’s important to take recovery seriously. If you haven’t properly recovered from your previous strain, you are at greater risk of injury. Excessive strain can also occur if your body isn’t prepared for the workout you have planned for that day.
The WHOOP issues weekly and monthly reports. You’ll automatically unlock the Weekly Performance Assessment tool after logging 14 recovery scores. For the Monthly Performance Assessment, you’ll need 28 recovery scores. These assessments include detailed breakdowns of strain, sleep, and recovery within that period. You can also see how you’ve performed versus other WHOOP wearers within your demographic.
As with any next-gen product, the WHOOP 4.0 has been modified with some additional functions that aren’t available with the 3.0. These include:
As I noted earlier, shipping delays prevented me from trying out the WHOOP 4.0 firsthand, so I can’t speak to this model’s modifications. However, their absence didn’t really affect my experience with the WHOOP 3.0, which was overwhelmingly positive. If you’ve used the 4.0, we’d love to hear your feedback on how well these new features perform and how much they’ve impacted your overall WHOOP experience.
At first glance, the WHOOP looks fairly nondescript. The tracker does not have a screen or interface of any kind. Everything you need to view is accessed through the app.
During our interview with Emily Capodilupo, WHOOP’s senior vice president of data science and research, she explained that the tracker was designed with simplicity in mind.
“We really wanted wearables to just disappear on your body,” Capodilupo said. She added that a smaller, more straightforward design translates to a longer battery life.
You can catch our full exchange with Capodilupo in the video above.
Important aspects of the WHOOP’s look and feel include the following:
In terms of appearance, the biggest difference between the WHOOP 3.0 and WHOOP 4.0 is sizing. The latter is about 33% smaller than the previous model.
The WHOOP is a subscription-based tracker. Rather than making a one-time purchase, you select a subscription plan after choosing a band design. The tracker and band are included with each subscription. Existing customers can purchase new devices from WHOOP’s online store.
Here are the nuts and bolts for buying a WHOOP tracker:
|Standard Subscription Options||WHOOP offers three standard subscription options:
The tracker and a band of your choice come with each subscription. Costs of the subscription plans differ for non-U.S. customers.
|WHOOP Pro||The company now offers a fourth subscription option. For an additional $12 per month, WHOOP Pro subscribers receive a 20% discount on all WHOOP accessories, one free accessory every three months, and free shipping and returns on all orders.|
|Shipping||If you reside in the U.S., the tracker will be shipped at a flat rate of $8.99. Shipping costs for accessories may differ. WHOOP also ships to Puerto Rico, Guam, Canada, Australia, New Zealand, United Arab Emirates, and most of Europe. Delivery costs depend on the location.|
|Returns||You can cancel your WHOOP subscription within 30 days of receiving the tracker and receive a full refund minus shipping costs. The company may or may not require you to return the tracker in order to qualify for a refund.|
|Warranty||Regardless of which subscription you choose, the WHOOP is backed by a one-year warranty. All accessories come with 90-day warranties.|
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