After we’ve been through the N1 ‘falling asleep’ stage, which typically lasts just a few minutes, we enter N2, which is the light sleep stage. At this point, our body begins to slow down.

“In your first sleep cycle, light sleep is essentially a wind-down,” Jones explains. “Your eye movement stops, your heart rate slows and your body temperature decreases. The brain waves slow, and your muscles relax.”

The brain still has moments of activity during this period, however. These unique brain waves are known as ’sleep spindles’, and they typically last between 0.5 and three seconds, with a gap of three to six seconds between each spike. While scientists are still trying to understand exactly why sleep spindles occur, they’re believed to play an important role in the formation and consolidation of memory.

Light sleep isn’t the bad thing it’s perceived to be – in fact, it’s pretty important