The average parent, on the other hand, only manages a 37.5 hour week. So what does that tell us? Apart from the fact the world has gone mad?
A report commissioned by Centre Parcs - I've been to one which was tremendous fun and, contrary to popular belief, not just a piece of spookily preserved woodland under a glass dome - has shown that childhood isn't for cissies.
There's barely a moment of downtime, what with chess club and science jamboree, rugby training and diving lessons - not forgetting the street-dance class on a Monday you only let your daughter do if she promised to get up extra early for Spanish breakfast club on a Thursday.
I'm in two minds whether to pour scorn at such intensive hothousing, or call Ofsted and ask them to put my children's extra-curricular schedule into special measures.
The eight-year-old does tennis on a Tuesday and multisports on a Friday. The 14-year-old sometimes talks about going to debating club, and spends the rest of her time styling either her bedroom or her eyebrows.
Um, that's it. Even I have to concede that's a pretty poor show. Over the years, the music lessons fell by the wayside because I can't tell a piano chord from an umbilical cord, swimming was too much like school (mermaid school, maybe?) and ice-skating was "a bit boring and freezing-ish".
Do I spend the "average" of five hours 49 minutes a week poring over books with the small one? No, I do not. A single Roald Dahl chapter and that's her lot; if she wants to know what happens next, she'll have to read it herself.
I'm not sure anyone ever read a story to me as a child. I say this without mawkish self-pity; my father died when I was two, and my mother was too busy and exhausted bringing up five daughters and working full-time to do more than get us each a library card.
She never noticed that my elder sister was a sci-fi obsessive or that, between the ages of nine and 13, most of the books I brought home were about Hitler, but as I ended up eventually studying Goethe rather than becoming a neo-Nazi, no harm done.
That was the thing about analogue childhood: there was plenty of time. So much of it - too much of it, really. Yes, we were bored, but nobody cared. They certainly never took it personally.
I know a mother who says she feels like an abject failure if her children complain of boredom. Crikey, talk about over-identification.
As I recall, the upside to Seventies boredom was that it stimulated the imagination and led to creative thinking, even if the creativity only extended to making miniature gardens in shoebox lids or alphabetising all the random objects in the cupboard under the stairs.
My laissez-faire approach is to fill the gap between school and bedtime with very little. There are books and toys, and I can sometimes be bullied into baking, but mostly there is homework to be done and a range of critters to be played with and cared for.
When I think of my happiest times growing up, they were filled with pets, not prizes. In place of rosettes and trophies, my children have tropical fish, dogs and reptiles. Last weekend, we took possession of a terribly handsome chameleon, Cornelius, who lives in a brightly lit vivarium in the sitting room. We've barely turned on the telly since.
But I'd be lying if I claimed we lived in Durrell family bliss. There's a deal of difference between Corfu and north London (Cornelius needs a heat lamp, for a start), and when a friend boasts about her 15-year-old's proficiency at choral singing or urban sculpture, a part of me wonders if I (or, better still, my husband) oughtn't to push my children harder to excel at something marvellous.
If only I knew what. Neither seems at all interested in maths club or Hitler's formative years, and I instinctively cavil at the thought of flogging them through tap dance or judo or expensive sailing courses in order to acquire qualifications for qualifications' sake.
That's not to say some children don't thrive on a rigorous timetable of structured activities. Of course, there are those who like nothing better.
I just hope I don't discover in 10 years' time that those were my children, lying awake at night wishing their slacker mum would enrol them in more extra-curricular classes.
Somehow, though, I doubt it. It's not that I don't take their education seriously, but I take their childhood seriously, too.
In a social media culture of instant gratification, time and headspace are valuable commodities. I'd rather fritter an hour shooting the breeze with poster paints at the kitchen table than dutifully driving them to art club. Assuming they'd agree to go.
Right now, my main aspiration is that my girls excel at a Marvellous Childhood.
There's plenty of time to put in a 46-hour week, but it sure as heck isn't when you're still young enough to need ferrying around by your mum and dad.
