Question: what happens to your body when you sleep

Alex Reid answered on 7 Nov 2018:

Great question! Your body does lots of interesting things during sleep. As scientists we need things to measure, we could not do our job without measurements! Even though as psychologists we are really interested in the brain, to get our measurements from sleep we actually have to pay close attention to what your body is doing. We use this information to give us clues about what sleep stage you are in (there are several different types of sleep). We usually get this information from sensors we attach to your head and face. We then read signals from these (like a musician reads a sheet of music) to figure out what is going on. To answer your question more directly we look at muscle tone (in lighter sleep you get floppier), eye twitches (which tell us when you might most likely be dreaming), and brain activity which changes a lot overnight (it can ‘slow down’ and ‘speed up’). We could also look at heart rate, which also slows during sleep, and body temperature which tends to drop. However, for the most part, we can accurately determine your sleep stage just from the signals we get from your head (eyes, scalp and chin).