Sleep deprivation is rife in Britain and a recent study from Direct Line Life Insurance hints at the scale of the problem.

Over 7.5 million people (14 percent of adults) sleep for less than five hours a night on average which health experts say is dangerous to both mental and physical health.

There are numerous causes of sleep loss and some can be benign, such as erratic working hours. However, sleep deprivation can also signal a sleep disorder.

According to Doctor Holly Milling, Clinical Psychologist and Founder of The Sleep Practice, there are three telltale signs of a sleep disorder.

She explained: "If you’re struggling to sleep, waking up feeling unrefreshed or experiencing extreme daytime sleepiness on a regular basis, talk to your GP or a sleep specialist." 

According to the doctor, if you recognise any of the above, it may be that you have a sleep disorder, which may need more specialist support.

There are many different types of sleep disorders. They're often grouped into categories that explain why they happen or how they affect you.

Some common types of sleep disorders include: Insomnia, Sleep apnea, Restless legs syndrome (RLS), Narcolepsy

Sleep disorders can also be grouped according to behaviours, problems with your natural sleep-wake cycles, breathing problems, difficulty sleeping or how sleepy you feel during the day.