Sleep gives the body a vital opportunity to rest and build up strength – a good night’s sleep is essential for good health. Lack of sleep is associated with reduced concentration and irritability, and can affect a person’s ability to perform certain tasks. If it continues for long periods, lack of sleep can lead to excessive daytime sleepiness and it can also harm the immune system. There is also a link between sleep deprivation and depression.

If someone has a persistent problem falling or staying asleep which affects their daytime functioning, they are said to be suffering from insomnia. Around a third of people in the UK suffer from bouts of insomnia.