9 Of Life's Most Important Questions Answered By Science

3. How Does Coffee Work?

Many of us know that a good old cup 'o joe is enough to give a jolt of much-needed energy, but have you ever stopped to wonder how or why?

If it were a simple case of energy, a spoonful of sugar would have the same effect, but this is definitely not the case. Caffeine actually works, not by giving you more energy, but by blocking the neurotransmitter that makes you feel tired.

The longer you stay awake, the more a neurotransmitter called adenosine attaches itself to your neurons and slows their firing rate. Caffeine mimics the structure of adenosine, attaching itself to the neurotransmitters and thereby blocking the adenosine, but without having any effect on firing rates.

This does mean that, whilst it is good for short-term alertness, caffeine will not work indefinitely and you will eventually run out of energy. If you're feeling sluggish, the thing that really clears out all of that pesky adenosine is a good sleep.