Sleep calculators
If you’re among the 55 per cent of Australians who say they aren’t satisfied with their sleep, the thought of being able to enlist a device to help turn things around sounds understandably appealing.
Recently, people have been turning to ‘sleep calculators’ for exactly that reason, but the jury remains out on both their effectiveness and the theory behind their design.
How do sleep calculators work?
Essentially, you punch the time you want to wake up into the calculator and it provides a selection of suitable bedtimes, for that night.
But it’s a lot more complicated than simply counting back seven or eight hours from your preferred wake-up time. In calculating a few different ideal bedtimes for you, sleep calculators account for the fact that we all have around five or six sleep cycles a night, and that there are better times – or
sleep stages – than others to wake up in during a sleep cycle if you want to feel as refreshed as possible in the morning.
For example, if you want to wake up at 7am, according to a sleep calculator the best times to hit the sack are either 9.45pm, 11.15pm or 12.45am – depending on how many hours sleep usually leaves you feeling refreshed.
The theory is that by going to bed at one of those times, when your alarm goes off at 7am you’ll be in the rapid eye movement, or REM stage of sleep. And people often feel most refreshed when they wake up from REM sleep compared to waking up during another sleep stage.
What’s the potential problem?
Before you start planning your entire night around the go-to-bed time a sleep calculator prescribes for you, it pays to know that not everyone is on board with the idea and the calculations behind how they work.
One of the main criticisms is that they’re based on the fact that a single sleep cycle lasts for around 90 minutes on average. In reality, not only can sleep cycles vary between 70 and 120 minutes, each of the five or six cycles you’ll experience in a night will be a slightly different length, too.
The other problem is that it might take you quite a while to fall asleep. If it takes a long time after going to bed to start pushing out those z’s, that will throw the sleep calculator’s timings out.
Plus, if the prescribed bedtime is too late, so that you go to bed sleep-deprived, or too early, so that you’re forcing your body to sleep when your circadian rhythm isn’t expecting it, that can also interfere with how your sleep cycles play out.
Combined, it means that despite the recommended bedtime being chosen so that you can wake up in the REM stage of sleep, there’s no real way of guaranteeing that’ll actually happen.
Why you should wake up at the same time each day
As far as your sleep’s concerned, timings are key. But rather than – or perhaps as well as – using a sleep calculator, the main thing to strive for is waking up and going to bed at the same time each day.
Research continues to show that doing this plays a vital role in
maintaining your circadian rhythm, or body clock. And that’s crucial because when your circadian rhythm is in good shape, you’ll find it easier to fall asleep at night and will feel more refreshed when you wake up.