Were You Born to Snooze?

Alarm clocks and I have never been the best of friends. Dozens of the little blighters have perished on my bedside table, mangled to a metallic pulp for daring to interrupt my slumber. Crucial morning meetings, job interviews, final exams, hospital appointments, weddings ... all have fallen by the wayside because I simply can't get up early.

It's beyond me -- as are those strange people who spring out of bed at 6am and have jogged, showered, shaved and breakfasted before I've hit the snooze button. Unsurprisingly, my friends, family and colleagues have long considered me a lazy good-for-nothing, despite the fact that I often write well into the evening while they're ensconced in front of the TV.

Finally, it seems I may have found support from an unexpected source -- Denmark's B-Society. This pressure group advocates the rights of " B-people" who, like me, are sluggish and bed-bound first thing, but whose energy spikes in the evening.

The B-Society's founder, Camilla Kring, is campaigning for fundamental changes in the way we learn, work and live. "Society is arranged around A-people, who are happy working from eight to four," she says. "We want to create a more flexible society, one which also accommodates B-people -- those who are genetically predisposed to wake and work later."

Her ideas have struck a nerve in Denmark, where the B-Society already has 5,000 members. Its manifesto, which calls for "an uprising against the tyranny of early rising," has persuaded the Danish government to support B-certified companies in offering flexible working hours. And, from next year, one school in Denmark will offer classes starting later in the day -- at 10am instead of 8am.

Kring bases her arguments on the notion that people have different " circadian rhythms". These rhythms govern our body temperature, hormone levels, heart rate and sleep-wake cycles. The circadian rhythms of B-people, such as myself, wake us naturally at 9am or 10am, after which we feel dopey most of the morning but start firing on all mental cylinders in the afternoon and evening.

The rhythms are controlled by a group of about 10,000 nerve cells in our brains called the suprachiasmatic nucleus (SCN), which acts as our internal clock. The SCN is activated by light, which enters the eye and is received by cells on the retina. Signals travel from the retina to the SCN via the optic nerve, and the SCN then sends messages to other parts of the brain that control temperature, drowsiness, hormone levels and so on.

Dr Roberto Refinetti, a biopsychologist at the University of South Carolina, is an expert on circadian rhythms. "These rhythms describe anything in the body that shows a daily oscillation," he says. "Your temperature rises and falls at the same time every day and you probably feel drowsy at around the same time daily. But circadian rhythms also control your blood pressure, glucose levels and much more."

So why do they vary from person to person? "Just as some people are taller and some are better-looking, some people's internal body clock synchronises with the outside world in a different way. And this can affect your performance. For example, in an Olympic competition, your circadian rhythm could make the difference between gold and silver, depending on the time of the race," he explains.

If you're not a finely tuned athlete, Refinetti believes, these differences are minor. He argues that, for mere mortals, body clocks ticking at different speeds won't make much difference to athletic or work-related performance -- which is bad news for my late-sleeping justification, then. Maybe I am just lazy after all!

Time to bring on another witness for the defence -- Professor Jim Horne from the Loughborough Sleep Research Centre. Horne is an expert of sleep research, with 30 years' experience of analysing our nocturnal habits. His terminology differs slightly -- he prefers the terms "larks" and "owls" to describe early and late risers. "About half the population is neither one nor the other," he says. "About 10 per cent are extreme morning or evening types. Most people are somewhere in between."