It’s common to associate moving about at night with poor quality of sleep. Yet from a scientific point of view, there is no correlation between moving around and the depth or quality of sleep. In fact, it is quite natural to move in your sleep: these natural movements are necessary for good rest, so you would not want to restrict or reduce them.
All of us naturally move up to 60 times each night: between 12 and 20 of these movements are major positional changes. One reason we move so much during the night is to relieve the pressure of lying in one position for any length of time. But there is also a second reason, and that is to help us moderate our body temperature. Good sleep depends on us reducing our body temperature during the night, and by moving around we are essentially alternating between cooler and warmer parts of the bed. Because of these natural position changes, your bed needs to work with you – allowing you to move without disturbing your sleep.
The link between sleep and movement is nicely illustrated by the story of the night before the first manned space flight. There were two possible cosmonauts – Gagarin and Titov – and that night they slept in special beds, their every motion monitored by strain gauges to determine the quality of their sleep. Gargarin worked out that the person who slept best would be chosen, so he stayed awake all night without moving a muscle!
The story shows that there is no direct correlation between lack of movement and depth of sleep. Moving while asleep is really nothing to be worried about – unless you’re planning a space flight, that is.