A waste of time or the answer to many of life's little problems?

Sleeping has never been something to be particularly proud of, which is unfortunate because I happen to excel at it. We spend about one third of our lives asleep, time that could presumably be spent doing more productive things. For some, this makes slumber difficult to distinguish from laziness. Napoleon, Michelangelo, Florence Nightingale and Margaret Thatcher are reputed to have got by on four hours of sleep or less every night. Along with a host of other famous and frenetic people, they have helped to perpetuate the myth that sleep is a waste of time.

"Sleep is the most moronic fraternity in the world," the writer and insomniac Vladimir Nabokov said in Speak, Memory. I remember feeling slightly insulted as I lay in bed reading his book. Moments later, my eyelids started to close and I fell asleep. Nabokov, I concluded the next day, was jealous. He envied the easy sleepers. He resented people like me who could simply drift off in a bed - or on a train.

One of the most difficult aspects of having children is lack of sleep. Astrid has never been very good at sleeping. She is too interested in clambering over things, chewing stuff, clapping her hands (a recently acquired skill) and traversing the bars of her cot in the manner of a climber scaling the north face of the Eiger. Even when she was immobile, she was too alert and curious to simply drift off. Once in six months she has fallen asleep in her bouncer rocker. It was a remarkable moment. She dozed for a few minutes and snapped out of it much like a worker caught napping at her desk. Astrid, it seems, has been born with the "sleep is for wimps" gene.

My wife, Lucy, has born the brunt of Astrid's sleeplessness, as she tends to her during the night. On good nights, Astrid wakes up two or three times. On bad nights, it can be half a dozen times. We tried sharing the burden by alternating the night shift, but it did not work. After Astrid had cried for many minutes, I would wake up and stagger around to the cot in a daze - by which time Lucy would already be awake. Nowadays I whisk Astrid away when she wakes up at 7am and Lucy sleeps until breakfast. It is not long, but it seems to be staving off a crack-up.

Make no mistake: lack of sleep is a serious problem. Sleep is a mystery that science has yet to unravel, but the consensus is that sleep deprivation shortens your life and affects how you think. A study at the University of Chicago in the 1980s tried depriving rats of sleep. All of the subjects were dead after 32 days. Keeping people awake is used as a form of torture. All in all, no sleep is bad. It erodes sense of humour, breeds lethargy, causes you to lose words you used to know or forget how to spell them. Worst of all, it leads to ill temper and aggression.

Sometimes I find myself seething with rage over petty things. It is inexplicable and irrational. Most of the time I realise lack of sleep is to blame and a nap is the answer. On the rare occasions I fail to see lack of sleep as the problem, I end up having an argument with Lucy over nothing. And since she is usually more sleep deprived than me, the squabble blooms into a fight and sometimes becomes a feud. The answer - in all cases - is to go to sleep. Perhaps if we slept more the world would be a more peaceful place.

I recently found some tracings from Astrid's foetal heart monitor taken before she was born. She was overdue, so she was monitored every few hours. The process led to page after page of graph paper with a thin line on it. The line was her heart rate. If she was sleeping it remained quite flat and about one third of the way up the page. If she was awake it zigzagged around two thirds up the page. I remember joking that it was her first work of art.

Looking at these pieces of paper now, the strange thing is the accuracy. Of course, the machine gave an accurate representation of Astrid's heart, but now that I have known her for six months, I know the line is an accurate representation of Astrid. It is identifiably her. It has accuracy of expression and fidelity to Astrid's personality. These pages of graph paper are her first mark on the world before she had even joined it. I will cherish them forever.