Were you born to snooze?

Can't get going in the mornings? You're not lazy, just a 'B-person'. It's your circadian rhythms, explains late riser Dan Roberts

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."

Happily for me, Horne thinks that owls such as myself have a good reason for our lie-ins. "The many studies we have conducted throw up very clear differences between larks and owls. Owls are more adaptable to shift work and jet lag, for example, and will work best in the afternoon and evening."

The causes of this difference aren't clear, though. "There does seem to be a genetic predisposition, but I think the main reasons people are larks or owls are environment, personality and social pressures. If you lead a late-night lifestyle – being a nightclub bouncer, say – your system may adapt to that. However, if you're an extreme morning type, you just couldn't do that kind of job," Horne argues.

The problem, of course, is that most jobs are adapted to A-people, morning types, larks, or whatever you choose to call them. My owlishness has caused me no end of headaches – so is there anything I can do to become more lark-like?

Dr Neil Stanley of the British Sleep Society thinks there is. "If you are a real night-owl and are going to sleep very late and waking in the middle of the day, you can shift your circadian rhythms by taking melatonin, or using light to get you back into a more normal sleep pattern."

Melatonin is the hormone produced by the body when it gets dark to make us feel sleepy. Stanley suggests either taking a melatonin supplement or dimming the lights earlier in the evening to encourage your body to secrete it.

Any other suggestions? "The other option, of course, is to find yourself a role that suits your sleep patterns," Stanley says. "If you're a night owl you may be best off working night shifts. One British haulage firm now screens its drivers to make sure that people work shifts best suited to their circadian rhythms."

And he agrees with Camilla Kring that our rigid working day is redundant now that technology allows us to work from home. "Our nine-to-five day is completely arbitrary," he says. "I have no idea where it comes from, but it certainly doesn't suit everyone. Why are our working hours not more flexible? And school hours really don't suit all children – some kids are useless at studying first thing."

I feel vindicated. It's not laziness; I'm just a B-person, hater of alarm clocks and early mornings and lover of late nights. Luckily, it seems I'm in the right profession. "A-people often work in finance or the legal profession, while B-people are usually journalists or creatives," Kring says. "Bs are much more flexible than As."

Of course we are. So, if you're a fellow B, next time you arrive at work bleary-eyed and an hour late, remember it's not your fault. Tell your boss it's those darned circadian rhythms.

Take the test: are you a lark or an owl?

1. If you had no commitments the next day, what time would you go to bed?

a) 8pm-9pm.....................5

b) 9pm-10.15pm.....................4

c) 10.15pm-12.30am......... 3

d) 12.30am-1.45am.....................2

e) 1.45am-3am.....................1

2. You have to do two hours of physically demanding work. When would you choose to do it?

a) 8am-10am.....................4

b) 11am-1pm.....................3

c) 3pm-5pm.....................2

d) 7pm-9pm.....................1

3. You went to bed later than normal and don't have to get up at any particular time. Which of the following is true?

a) Will wake up at the usual

time and not fall asleep again......... 4

b) Will wake up at the usual

time and then doze.....................3

c) Will wake up at the usual

time but fall asleep again......... 2

d) Won't wake up until later

than usual.....................1

4. You have a two-hour test to sit. When would you choose to do it?

a) 8am-10am.....................4

b) 11am-1pm.....................3

c) 3pm-5pm.....................2

d) 7pm-9pm.....................1

5. If you had no commitments during the day, what time would you get up?

a) 5am-6.30am.....................5

b) 6.30am-7.45am.....................4

c) 7.45am-9.45am.....................3

d) 9.45am-11am.....................2

e) 11am-12pm.....................1

6. A friend asks you to join him for a workout at the gym, at 10pm. How do you think you would perform?

a) Very well......... 1

b) Fairly well......... 2

c) Poorly......... 3

d) Very poorly......... 4

7. Do you think you are a "morning" person or an "evening" person?

a) Definitely morning......... 6

b) More morning than evening......... 4

c) More evening than morning......... 2

d) Definitely evening......... 0

Add the scores together and compare your score with the table below.

32-28 ......... – definitely morning

27-23......... – moderately morning

22-16 ......... – neither

15-11......... – moderately evening

10-6......... – definitely evening

The B-person's guide to staying awake

* Work in an industry that suits your daily rhythm, or work from home.

* Persuade your boss to introduce flexi-time so you can start late and finish late if you want to.

* Go to the gym in the evening – early-morning workouts are a definite no-no.

* If necessary, change your sleep-wake cycles with a melatonin supplement.

* Choose a B-partner, or mornings will be a constant source of conflict.

This an abbreviated version of a test developed by Professor Jim Horne. The full test can be found in his book Sleepfaring: a journey through the science of sleep (Oxford University Press, £9.50)