WHOOP 4.0 is a unique wearable health device that offers continuous monitoring of important physiological data, including heart rate, respiratory rate, resting heart rate, heart rate variability, skin temperature, blood oxygen levels, daily activities, and sleep to help you better ...WHOOP 4.0 is a unique wearable health device that offers continuous monitoring of important physiological data, including heart rate, respiratory rate, resting heart rate, heart rate variability, skin temperature, blood oxygen levels, daily activities, and sleep to help you better understand your overall health status and track your progress over time. Not only does it track what you did, but it also uses a science-backed approach to offer recommendations throughout the day based on your unique physiology-whether thats recommending when to go to bed, how to reduce your stress, or how much exertion you should take on to meet your health goals. The easy-to-use WHOOP Journal allows you to track and log your daily behaviors like activity, diet, alcohol consumption, stress levels, caffeine intake, and more.