Whoop is designed to be worn permanently to continuously collect data on your movement and recovery. A device without a screen and buttons, without notifications (except for an additional morning tactile alarm clock). It is lightweight and small enough to be almost invisible. The knitted band is extremely flexible and stretchy, making the device easy to wear during any activity or sleep.

Whoop 4.0 uses five LEDs and four photodiodes to determine your vital signs, including heart rate and skin temperature. These pieces of physical feedback track changes in heart rate variability (HRV), blood oxygen levels, resting heart rate, sleep stages, and exercise intensity. The app collects this data to help provide science-based recommendations and reports on how you’re recovering from daily stressors and activity.

Using the Whoop app is easy, but it can be a bit overwhelming due to the sheer amount of data to sift through. You’ll find detailed sleep metrics, recovery data, menstrual cycle, calories burned, exercise, and more. Your experience will be tailored to your individual goal, such as maximizing performance or increasing your overall activity level.

In the app, graphs, charts and daily reports will suggest optimizing your routines for better recovery. A daily journal allows you to track how variables such as medications, stressful events, exercise, and social time affect your health.

The app also has built-in coaching. With this feature enabled, you’ll receive suggestions on ideal routines for your goals, such as recommended bedtimes and how much you’ll do during your next workout. A variety of training plans and educational content are also available.

Trackers and bracelets are waterproof up to 10 meters for two hours. The tracker comes with a rechargeable rear battery that lasts for four to five days.