Deep Sleep is when we recover and rebuild, strengthen our immune system. The data could show what many thought intuitively: Pets could be good for us! The data also shows that sharing the bed with pets, in general, may improve deep sleep significantly. This stands as a challenge to some of the opinion-based sleep coaching. The data is clear for our large group of single Sleeptracker users: live with your pets and you may benefit from a more deep sleep. Females benefit even more than males. The data show that is true for both dogs and cats!
Here is a possible evolutionary explanation, if there is one. Alone in paleo times, solitary, one had to be on guard for the cave bear or the saber tooth tiger. That meant light sleep while monitoring sound in the background. With a dog, for example, we naturally allow ourselves to sleep deeper by relaxing more, trusting our pet to be our eyes and ears. Hence a potential evolutionary explanation of more deep sleep with a furry companion.