7 Theories About You That Will Make You Question Everything

4. Theres No Good Reason Why Sleeping Should Give You Energy

We generally think that there's nothing better than a good night's sleep to help you feel refreshed, alert and energised. We intuit tiredness as a lack of energy and sleep stops you from feeling tired, ergo, sleep must give you energy, right?

Wrong.

In terms of actually fuelling our bodies, we convert food and oxygen into energy to keep our cells working. That process is a pretty well-understood fuel in energy + waste out equation. Sleep, on the other hand, plays no part in replenishing your fuel stocks and, in fact, you continue to burn energy in your sleep. What's more, you can't simply "eat your way out" of feeling tired.

We know that sleep is important, but we don't know exactly what it is for. There are a huge variety of theories, including sleep as a memory and learning tool or even a way of giving the brain a chance to "clean" itself.

In general, the answer to "Why do we sleep?" is "Because we get tired.", but we're still figuring out why we get tired at all.