Waking up after a good night's sleep can make you feel invincible — and that's usually because you've clocked up plenty of deep sleep. But what exactly is deep sleep, and how can you get more of it?
We go through four different sleep stages as we nod off, but spending enough time in deep sleep is hugely important to the replenishment of our bodies and mind. However, various factors can impact how much deep sleep we get every night.
