Nine per cent of the population of Australia - more specifically, more than 1.5 million adults living in the country - suffer from sleep disorders. New research has calculated that the overall cost of these conditions to the Australian economy is more $5 billion (£3.4 billion) a year in direct and indirect costs. A study conducted by Deloitte Access Economics calculated the collective effects of Australians who toss and turn in their single beds as a result of sleep problems, and the losses caused through productivity, absenteeism and poor work performance. Conditions like sleep apnoea, insomnia and restless leg syndrome were found to have a total direct health cost of around $800 million (£542 million) a year and indirect costs, including workplace accidents and productivity losses, a total of around $4.3 billion (£2.9 billion). In an interview with ABC News, director of the West Australian Sleep Disorders Research Institute Professor David Hillman said: "What these conditions have in common is that they disrupt sleep and cause daytime symptoms: tiredness, lethargy and really suboptimal brain function. "I've dealt with people who actually believe they can train themselves to sleep less - that's simply not possible. Sleep is a physiological need that has to be met and if you don't meet it you can very readily measure the effects on brain function."