This is not strictly accurate. There is some daily mail science about “super humans” who need less than 7-8 hours. And while some people survive like this, your body needs sleep for 7-8 no exceptions. Deep sleep (as important as light sleep) only occurs during long uninterrupted phases. During those phases your body does some amazing things. Amongst other things the production of things like cancer fighting cells and repairing all the physical and mental streses of the day. While not fully understood exactly what, we know the why and lots of good studies prove the correlation between regular quality sleep and better mental and physical well being.