It's nine-to-five no more. No matter what time it is, in our 24-hour seven-day-a-week society, work demands more from us. Our sleep patterns are shifting. Chris, it's 11 o'clock. All right, thanks. Take the Jarvis family. When milkman Chris is getting up to work through the night, his wife Carol, a housekeeper, is going to bed. Their son is working nights down at the local supermarket. One in ten of us now has just five hours' sleep or less a night. Chris, for example, misses a massive six weeks' sleep a year. I almost quite looking forward to getting up, you know, I really enjoy what I do, and if you enjoy your work, sleep's not a problem really. In this house, there are three people who work shifts, the parents and the son. Increasingly around the country, it seems that the bedroom is becoming an office, as people use laptops, send emails and use their mobile phones from their beds. Nik Done's an ambitious 20-something in Public Relations. Her bed's the nerve centre of her life. You can sit here, cross-legged, loads of space, get papers out across the whole bed, and it's great, certainly nicer than an office at seven o'clock in the morning. Researching sleep, scientists at Surrey University warn workaholics of the dangers of sleep deprivation. We will make more mistakes, there will be more errors, there will be accidents related to sleepiness. There may be more serious health consequences. It is known that shift-workers have an increased risk of cardiovascular disease. So with health in mind, scientists say it's time to take sleep seriously before it's too late. Nicola Carslaw, BBC News.