My husband Sean and I have been married for five years, and by day, our relationship is fairly robust. We laugh at the same things (dogs in cars, my mother's emojis), get furious about the same things (misplaced commas, the price of organic carrots) and generally want to do the same things (go for long walks, eat Thai food, listen to David Bowie).
During daylight hours, we are perfectly compatible. But by night, the cracks emerge, and I'm despondently forced to conclude – to quote Emily Brontë – that our souls are as different as a moonbeam from lightning, or frost from fire. When it comes to sleep, Sean and I are hopelessly mismatched.
![One bed, two very different bedtimes.](/web/20161109011441im_/http://www.theage.com.au/content/dam/images/g/s/g/2/8/f/image.related.articleLeadwide.620x349.gsg287.png/1478048375218.jpg)
The main schism is that our souls inhabit different time zones. My ideal bedtime hovers between 11pm and midnight; Sean's falls a good two hours earlier, around 9.30pm. He wakes up at 5.30am; I prefer to sleep until 8am.
Since childhood, I've been reluctant to go to bed. I'm a night-time potterer whose most productive hours come after 9pm. At university I'd cheerfully pull all-nighters to write essays and today, as a freelance writer, I regularly work until 3am, enjoying the mental clarity and focus I can only attain when the rest of the world has buggered off to bed.
Sean, on the other hand, is a self-proclaimed morning person who insists his brain shuts down after 8pm. He says he can't even focus on a movie after 8pm, not even a 1980s comedy. Right around the time I'm feeling my most focused, creative and sociable, Sean is yawning and flicking off his internal light switches.
Back in the 1970s, biologists and psychologists began exploring the difference between early birds and night owls. In 1976, researchers James A. Horne and Olov Östberg developed the morningness-eveningness questionnaire (MEQ ), a self-assessment tool using 19 questions to determine a person's peak alertness periods. Recent research in the field of chronobiology – the study of biological rhythms – indicates that every person has their own chronotype, or internal clock, which varies greatly between individuals.
Dr Till Roenneberg, professor of chronobiology at Ludwig-Maximilian University in Munich and a leader in the rapidly expanding field of sleep science, explains: "A biological clock ticks in every person, producing an individual daily timing."
Internal clocks evolved to help people during naturally bright days and dark nights, but in the intervening centuries humans have changed their environment dramatically. "With decreasing exposure to daylight from working inside and increased exposure to artificial light after sunset, we have drastically weakened the signals used by our clocks to synchronise to the 24-hour day."
A person's chronotype is largely determined by genetics, but gender and age are also factors, he says. Women tend to go to bed and wake up earlier than men by up to two hours.
In this Sean and I are unusual, and a quick poll of my friends confirms that it's normally husbands and boyfriends who stay up until 2am re-watching The Wire, while women more readily foster early-bird habits like a 20-minute Headspace meditation before breakfast.
"It drives me mad that Elliott stays up until 1am listening to music on his headphones when he knows I have a 6am yoga class the next day," my friend Leonie says. "But I guess we both have our rituals."
Issues arise, however, when there's a significant mismatch between our innate sleep pattern and the schedule that our lives demand of us. "'Social jet lag' refers to this difference between our external social timing and that of our internal clock," says Dr Roenneberg.
More than 60 per cent of us sleep with other people – known as "dyadic sleep" – and it's a rare couple whose chronotypes match. About 40 per cent of Dr Roenneberg's research participants live with social jet lag greater than two hours, which can be particularly problematic in relationships.
For Sean and me, the issue of sleep incompatibility came to a head a few years ago when he retrained as a horticulturist, the ultimate career choice for any irritatingly perky early riser. In order to start work at 7am, he'd rise at 5am – necessitating a bedtime of 9pm – for a "leisurely breakfast" before cycling to work. I've never felt I was missing much by sleeping in until 8am, and I can still be out the door by 8.30am – mornings mean nothing to me
Evenings, however, are precious, the long-awaited reward for a day of solitude and hard work at my desk – gilded hours that promise friendship, romance, wine, carbohydrates and Netflix.
I work from home and rarely finish before 7pm, and I realised with horror that our new quasi-military regime left me with two meagre hours for my non-work existence. Two hours' overlap in which to see friends, eat dinner, watch The Bridge, fit in a yoga class – to have a life beyond the parameters of my MacBook screen.
It wasn't enough. For a while, I did my own thing, going out with friends or simply pottering around the flat until my natural bedtime of 11pm. But it became lonely – with Sean in bed before I got back and leaving before I woke up, he felt more like a snoring hot-water bottle than a soul mate. As the UK writer Tim Dowling observed in his book How to Be a Husband: "Sex, for the most part, happens between couples who go to bed at the same time. It's fine to stay up later than your partner, as long as you bear in mind that you are effectively choosing between sex and [current affairs show] Newsnight."
And so I dutifully tried to turn myself into a morning person, which felt much like trying to turn myself into a Scientologist.
I could handle the early starts, but I couldn't do the early nights. There was no retraining my brain, which stubbornly remained most active around 9pm. If I'm up and about, I can channel this second wind of mental energy into writing, booking an Airbnb for our next holiday or puzzling over the details of Making a Murderer. If I'm in bed, my thoughts have nowhere to go but the deepest, darkest recesses of my mind, dredging up embarrassing childhood memories, professional insecurities and miscellaneous anxieties about the future.
This brings me to another chasm between sleeping Sean and me: he is a good sleeper, and I am rubbish at it. He looks forward to getting into bed, a sensation that, as a lifelong periodic insomniac, is alien to me. Sean, though, sleeps like a log – and sounds much like a log being chain-sawed. Yes, he snores, something that adds to the overall imbalance in our sleeping lives.
My experience of failing to turn myself into a morning person comes as no surprise to Dr Roenneberg. "It is very hard to override your internal clock in order to spend more time with your partner," he said. "If you don't sleep during your own internal timing window, you aren't as socially capable or as effective at work, and you will automatically blame your spouse."
Instead, the most common expert advice for sleep-incompatible couples like Sean and me is to embrace our different internal time zones.
"It's healthy to have quality time away from your partner," insists Roenneberg. "We need to accept that our significant other might not always be available."
When it comes to relationships and family life, Roenneberg argues, disparate sleeping patterns make us more efficient, independent and ultimately better parents and partners.
So, sod 7am. The hours after 9pm are mine. All mine.