It is well known that people need at least 8 hours of sleep every night in order to have enough energy during the following day. If you do not sleep enough you will not have enough energy and you will need to stuff yourselves with energy drinks and coffee.
The lack of sleep will surely be shown onto your face.
BuzzFeed made a video in which is shown the looks of people who have lack of sleep and their looks in the future. Watch the video and see for yourselves how lack of sleep affects us.