Without stress, we wouldn't have got where we are today. Our cave-dwelling ancestors would have perished at the hands of bigger-toothed beings if our bodies had not been designed to secrete energy-boosting stress hormones that warn us of danger.

Now, the average person who doesn't need to wrestle a rival for a lunch or take flight from a wild animal still utilises stress to meet day-to-day challenges, but too much can have a negative effect. The hormones associated with stress - cortisol, adrenaline, norepinephrine - are beneficial in small doses but can be difficult to control and harmful to the way our bodies work.

COMMON CAUSES OF STRESS & HOW TO AVOID THEM

1. WORK

"Do what you love and you'll never work a day in your life." The old saying makes it seem so simple, but many people choose their career path as teenagers - a time when frankly you have more pressing matters to attend to. Being unhappy at work can make you feel like you're wasting the best hours of the day, but things can change...

23 ways to avoid stress