Sleep deprivation is more common than previously thought. In Europe, almost a third of adults suffer from sleep disorders - and it has a huge impact on how people perform at work. 

It also leads to extremely high economic cost. A study, published in the European journal of neurology, calculates an economic impact of more than $400 billion across the continent, each year.

"I always needed to take a nap at work because I was very tired and couldn't sleep through the night," says Vienna resident Franz Rechtberger while trying on a new respiratory support device to help his sleep apnea. Pauses in his breathing used to wake him several times every night.

It is one of the most common sleep disorders but it often goes undiagnosed, so around 80 per cent of apnea cases are not treated.

"Patients may have trouble concentrating, or remembering things at work," says Katharina Muhlbacher who runs the department of sleep medicine at Vienna's Herz Jesu Hospital. 

"Also in their private life, they feel irritated, often to the point of depression. It can lead to traffic accidents, even accidents at work and prolonged sick leave. The consequences of untreated sleep apnoea cost the economy more than treatment and prevention," she adds.

Muhlbacher says cases of apnea are rising due to its correlation with obesity and old age which are increasing. But there's now more awareness.

"Many people now have smart watches where they might notice in case their oxygen levels aren't right, and choose to go see a doctor," she says. "That's actually a very good development."

Last year, Muhlbacher and her team started to offer remote diagnostics. Patients can document their sleep from home without needing to spend a night at the hospital - lowering the clinic's waiting lists.