Apple Watch sleep tracking: How new update encourages you to get to bed

In an exclusive interview with The Independent, Apple exec Kevin Lynch reveals the company’s newest Apple Watch feature, sleep tracking

General view of the Apple Watch during the Apple Covent Garden re-opening and iPhone XR launch at Apple store, Covent Garden on October 26, 2018 in London, England (Stuart C. Wilson/Getty Images)

“We have spent a lot of time learning about the science of sleep,” Kevin Lynch, Vice President of Technologies at Apple, tells me. We’re talking on the phone a couple of days after last week’s fast-paced, jam-packed World Wide Developers’ Conference keynote address, where the company reveals what innovations will be delivered later in the year for the iPhone, iPad, Apple TV, Mac and Apple Watch.

The section on advances coming to Apple Watch talked about new Watch faces, improved routing for cyclists in the Watch’s Maps app, a cool handwashing app that notices when you’re washing your hands and what was arguably the biggest update: sleep monitoring.

It’s widely acknowledged that sleep is one of the main pillars of health, so anything that can encourage you to get enough sleep is a potentially important benefit.

I’ve been asking Apple executives about sleep tracking on the Watch for years now, ever since the company bought Beddit, a company that makes sleep tracking devices which slide under the mattress, back in 2017.

Now, it’s a reality, and it works just from your wrist. The new Sleep app will arrive with the next Watch operating software, watchOS 7, this autumn. It will work on Apple Watch Series 3 or later.

But where other sleep tracking apps concentrate just on the sleep part, Apple’s involvement begins before that. Lynch explains that the focus, “Is really about getting enough sleep and the main thing about that is the difficulty of going to bed. There are so many things in the world to distract us and occupy our attention. Supporting people in managing that transition is where the magic is.”

So, you set up the Sleep app by choosing a bedtime and the number of hours’ sleep you hope to achieve. You can add extra parameters, such as choosing a playlist of restful music, adjusting any smart home lighting, adding a meditation app to your pre-bedtime activities and so on. But that’s all you have to do – you don’t have to tell it when you’re actually going to bed, for instance.

The process benefits from the fact that the iPhone and Apple Watch are already familiar elements in people’s lives. “The honour we have with iPhone and Apple Watch is that we're already present with people and we can use some of these moments to help them so they can shift their focus more towards going to sleep. The way we did this was we built something called Wind Down.”

As time ticks nearer to your chosen bedtime, the screens on your iPhone and Apple Watch become dimmer. The iPhone moves to the Wind Down screen which gently reminds you bedtime is coming and offers you your chosen pre-bedtime activities.

Eventually, the Watch display turns off, only showing a pale, simple digital clock face if you tap it and muting the notifications that would otherwise appear. Lynch says Apple found that using the operating system to change your mental approach to going to bed was especially helpful, and the team sought to deliver something not found in other sleep apps, creating something beyond notifications.

Once you’re asleep, the Apple Watch uses its accelerometer to track micro-movements such as the rise and fall of your breath, which reveals whether you’re awake or asleep. The Watch has an optical heart rate monitor so it can track your heartbeats as you sleep, too. All the information it gleans is stored in the iPhone’s Health app, though the Sleep app on the Watch also reveals how long you slept last night, the night before, last week and so on.

The Apple Watch has an alarm that’s designed to wake you gently, either with sound or with a subtle but increasingly insistent tap on the wrist if your Watch is set to silent. This has the advantage that it doesn’t wake a slumbering bed companion.

Your Watch greets you with a screen that cheerily wishes you good morning, shows the battery level in case you need to recharge, and today’s weather. All in big text so you can read it even if you’re, as Lynch says, a little blurry as you wake up.

Apple claims that battery life on the Apple Watch is 18 hours, though I generally find I have 40 per cent battery left at the end of the day. The company says you need to have 30 per cent battery an hour before you go to bed to be sure of getting through the night. Less than that and you’ll see a reminder to charge it before you turn in. More than that and it can be recharged in the morning, while you’re in the shower, say.

Some sleep apps are very specific, drilling down to whether you’re in light, deep or REM sleep. Lynch suggests that in terms of sleep states, the relevance of different stats is not universally agreed on, and much is still being researched about how REM states and depth of sleep relate to overall health. Plus, basing judgements just on movement may not be accurate enough for Apple. Lynch says, “In our testing, what we've found is that it's very difficult to understand what's going on in your brain from a device that's not reading the electrical signals of your brain.”

Apple has deliberately focused just on whether you’re asleep or not. This stems from a desire to avoid overwhelming users with data.

“In any of these adventures we go on when building things here we ask, what will make the most difference for people that, from a mainstream perspective, will be easy, helpful and empowering,” Lynch explains.

Apple’s approach, he says, “In terms of measuring your sleep, and this is a philosophy that we've used across Apple Watch, is to reinforce positive behaviour. For example, we congratulate people on meeting their sleep goals, so if you've set a goal of sleeping for some number of hours and you keep hitting that goal or exceeding it, Apple Watch will congratulate you on that. If you don't meet your sleep goals, then it doesn't say anything.”

Apple’s focus on health has been central to the Apple Watch since the first one in April 2015, when an optical heart rate monitor was included to ensure accurate counts for steps and calories. Over the years, the Watch has learnt to warn when the wearer’s heart rate goes unexpectedly high or low and added the capability to record an ECG. Sleep monitoring is the latest health addition.

Although the Sleep app doesn’t officially arrive until the autumn, there is a public beta software version available from July.

There have been third-party sleep apps available for the Apple Watch for years, including some which are accomplished and effective. But the effect of Apple including its own app on the Watch seems likely to lead to an increased awareness of such apps and, ultimately, a more widespread understanding of the importance of getting a good night’s sleep.