It's UK Coffee Week - here's 12 things it's doing to your health.

1. The stimulating effects of coffee can start 15 minutes after drinking and last for up to six hours.

2. The caffeine in coffee blocks chemical signals in your brain, stopping you from feeling tired.

3. Coffee improves mental ability - reaction times, memory and reasoning skills.

4. Your body and mind gradually build up a tolerance to caffeine.

Some studies have suggested that, like with drug addiction, the brain tries to return to its normal function while under "attack" from caffeine by creating more adenosine receptors.

5. Coffee won't help you sober up, contrary to popular belief.

6. Patients who wake up after anaesthesia with a bad headaches find that a cup of coffee will help.

7. More than four cups a day could shorten your life if you're young

An American lifestyle study of people aged 20 to 87 found that drinking large amounts of coffee (more than 28 cups a week) increased death rate by more than half in people under 55. It had no effect on older people though.

8. A cup of coffee while pregnant increases the chances of giving birth to an underweight baby.

Last year a Scandinavian study found that a daily dose of 200 to 300 milligrams of caffeine increased the risk of a baby being small for gestation age by up to 62%.

9. If you quit caffeine you might experience headaches, irritability, nervousness, nausea, constipation and muscular tension.

10. Coffee can cut your Type 2 diabetes risk.

Experts have found that by increasing intake by more than one cup a day was associated with an 11% lower risk of Type 2 diabetes over the next four years. Researchers from the Harvard School of Public Health in the US found that People drinking three cups or more were 37% less likely to develop Type 2 diabetes than those consuming one cup or less.

11. Women taking birth control pills metabolise caffeine much slower that other women do.

12. The same goes for smokers - caffeine takes longer for a smoker's body to process.