我们每个人每天都需要足够的睡眠来保持和恢复体力。睡眠不足所带来的负面影响有哪些？一项研究发现缺觉不仅会影响我们的身体健康而且还会给我们的心理健康造成危害。

How much sleep do you need? Do you find that if you don't get enough shut-eye and wake up feeling dopey, you spend the rest of the day in a bad mood? I certainly need my eight hours a night and that's important according to research, because bad sleep isn't good for our health.

We all need a good night's rest to recharge our batteries, but according to the Sleep Council in the UK, the average Briton gets six-and-a-half hours sleep a night, which for most people is not enough. It's tempting to cut back on the sleep we get, after all there are plenty of other more fun or useful things to be doing. Sometimes the pressure of work or a long commute means that our head hits the pillow much later than it should. But lots of studies have shown that cutting back on sleep, deliberately or otherwise, can have a serious impact on our bodies.

Studies have proved that sleep deprivation has a negative effect on our bodies but it can also have an effect on our mental health. A BBC programme called Trust Me, I'm a Doctor ran an experiment with the University of Oxford and was surprised to discover how quickly the mood of the people they were testing changed when their sleep was restricted to four hours a night for just three nights. Doctoral student, Sarah Reeve, who ran the experiment, said: "There were increases in anxiety, depression and stress, also increases in paranoia and feelings of mistrust about other people".

This and other research into the mental health of students, has found that the lack of sleep increases our negative emotions. I know that when I'm sleep deprived, it is harder to feel positive about things or even think straight! Daniel Freeman, professor of clinical psychology at Oxford University, agrees that insomnia is bad for our brain. He says: "We have more negative thoughts when we're sleep-deprived and we get stuck in them".

Bad sleep doesn't automatically mean you'll get mental health issues but other studies have shown that depriving people of enough sleep for only a few nights in a row can be enough to put healthy adults into a pre-diabetic state. So with all this evidence maybe we should concentrate on sleeping well. This means going to bed at a sensible time and creating the right environment in the bedroom to relax and sleep in. There's also the modern distraction of using smartphones and tablets at bedtime, tempting us to stay awake. The blue light emitted by electronic devices makes us feel less sleepy. And using them stimulates our brain when it should be winding down. What helps you get a good night's sleep?