While you are thinking about tiredness, here are some more sleep-related questions to ponder:
Why exactly do we yawn?
Could you train yourself to function on less sleep?
Is it true that people are either larks or owls?
What do animals dream about?
When we dream, does time pass faster or slower?
… and why don’t we say goodbye to winter tiredness altogether and hibernate like other animals?
For more videos subscribe to the Head Squeeze channel on YouTube.
If you would like to comment on this video or anything else you have seen on Future, head over to our Facebook page or message us on Twitter.