Why is young generation always tired and sleepy?

Trouble getting up on school days, dozing off in class, marathon lie-ins at weekends ... You’d be forgiven for thinking teenagers sleep their lives away.

In fact, the opposite is true. Sleep experts say teens today are sleeping less than they ever have. This is a worry, as there's a link between sleep deprivation and accidents, obesity and cardiovascular disorders.

Physiological changes, social pressures and external factors such as TVs and other stimulating gadgets in the bedroom contribute to late nights and mood swings.

Lack of sleep also affects teenagers' education, as it can leave them too tired to concentrate in class and perform to their best ability in exams.

Teen sleep thieves

Our sleep patterns are dictated by light and hormones. When light dims in the evening, we produce a chemical called melatonin, which gives the body clock its cue, telling us it’s time to sleep.

“The problem is that society has changed,” says Dr Paul Gringras,

consultant paediatrician and director of the Evelina Paediatric Sleep Disorder Service at Guy’s and St Thomas’ Hospital in London.

“Artificial light has disrupted our sleep patterns. Bright room lighting, TVs, games consoles and PCs can all emit enough light to stop the natural production of melatonin.”

Other distractions include mobile phones and instant messaging, which teens may use well into the night.

These all worsen the usual changes taking place in the body during adolescence, which means teenagers fall asleep later in the evening.

“That wouldn’t be a problem if there was no need to get up early in the morning for school,” says Dr Gringras.

“The early-morning wake-ups mean they’re not getting the average eight to nine hours of sleep. The result is a tired and cranky teenager.”

Several school districts in the US have introduced later start times for pupils in an effort to improve their performance, although results have been mixed.

How the body clock affects sleep

"Catching up on sleep at weekends isn’t ideal. Late nights and long lie-ins further disrupt the body clock," says Dr Gringras.

In severe cases, an individual’s body clock can be so different to everyone else's that they can’t fall asleep until late at night. This condition is called delayed sleep phase syndrome (DSPS). It's similar to the feeling of jet lag and is a disorder of the body’s timing system.

Treatment for DSPS includes bright light therapy – such as exposure to a bright light for about half an hour every morning – and chronotherapy, which involves restoring the individual’s natural sleep phase.

“Sometimes we give a small dose of melatonin in the evening, about an hour or so before bedtime,” says Dr Gringras. “Over the long term, this helps to reset the body clock.”

“However tired they feel, they should avoid lie-ins at the weekend. They should get exposure to outdoor light,” he says.