Apple fans have speculated for years about when the company's smartwatch would start tracking sleep. Now it's finally arriving with the next version of the Apple Watch's software, WatchOS 7, and it's a little different than what we've seen before.
Apple unveiled its sleep tracking features at WWDC, its developer conference, last week. But it's not a new area of interest for the company. Kevin Lynch, Apple's vice president in charge of Apple Watch software, told CNBC that the company has been extensively researching sleep technology for years.
"Some of these things are nonobvious when you first start working on sleep and it took us a while to get there," he said.
Thanks to this research, Apple decided to focus its efforts on setting and achieving simple goals, rather than collecting and analyzing data about a user's sleep habits. It might not be the right tech for those who are fixated with data and tracking their phases, like the number of hours they logged rapid eye movement sleep. But sleep medicine experts, who are wary of arming consumers with too much information without sufficient context, told CNBC that it's one of the better approaches out there.
Here's how Apple's sleep tracking tech works and why it stands out from the pack:
Some people love tracking their health data in the most granular way possible. Some devices from Fitbit and others offer a window into understanding these various sleep phases, including light sleep, deep sleep and rapid eye movement sleep, using motion sensors and heart rate tracking.
But too much information can also create negative outcomes. Experts recently coined a new condition called "orthosomnia," which involves a person becoming so preoccupied with getting the perfect sleep via wearable devices that they develop sleep-related anxiety. That might make it harder for them to get a decent night's sleep.
Dr. Seema Khosla, medical director of the North Dakota Center for Sleep, has seen these patients in her clinic. Armed with data from wearable devices, they've shared unfounded concerns about their sleep quality and duration.
"I've had patients get really worked up," she said in an interview with CNBC. "It's made me come around to the idea that we need to be a lot more thoughtful about the data we show."
Apple's Lynch suggested that information collected via smartwatches about sleep isn't always accurate. The company researched all kinds of sleep tracking, including to record brain waves via an EEG, over the years, and determined that it's very challenging to measure "a complete picture of what's going on in the brain" with just a wrist-worn device.
In addition, Apple doesn't typically like to give bad news to its users, including that they aren't sleeping properly. So the company has provided very minimal data about sleep duration and sleep quality. It's possible to see periods of wakefulness and sleep, but not the most detailed information around sleep cycles.
Instead, Apple asks Apple Watch wearers to set a goal around how much sleep they'd like to get, and then nudges them to wind down before they go to bed.
Ultimately, Lynch said, it's about tapping into user psychology.
"We wanted to be seen as a helpful addition, rather than another source of frustration and anxiety," he said. "We try to take the broad ideas of what is possible and hone it down as simply as we can, and then try to simplify it some more."
Apple's former sleep czar, Roy Raymann, who is now the chief scientific officer at sleep tech company SleepScore Labs, agreed with that approach.
"In general, consumers are looking for tools to improve, not for tools to measure," he said. For example, Raymann said that stepping on a bathroom scale isn't going to help a person lose weight tomorrow. In the same way, overloading a person with data about their hours of rapid eye movement sleep might not help them sleep better.
"So [Apple] focused on the measurement as a way to hit sleep health goal behaviors, which is a holistic view I support," Raymann said.
One of the new features involves a setting called Wind Down, which is designed to help users get to bed earlier. The idea is that people can set up a bedtime routine with their watch, including using a meditation app while the screen darkens and notifications are muted.
In the morning, the Apple Watch has a silent vibrating alarm or can make quiet sounds to wake up the user slowly.
Apple's Lynch said that the company put a lot of thought into Wind Down because it got consistent feedback from users that their biggest challenge was bedtime.
"So we looked at the techniques we can use to help support people in their transition to sleep," he said. "It's a balance of supporting and reminding."
Khosla said that the feature reminds her of the kind of thing that she'll do manually for her own patients. Typically she programs a bedtime alarm for them, which means that all of their devices need to be turned off. At that point, they stop scrolling through social media.
"I've had a few patients who really liked that, and even made it impossible to have functionality on their phones after a certain time," she said.
Other sleep medicine experts said that the Wind Down and tracking features are useful, but that an electronic gadget isn't necessary to improve. Sometimes, pen and paper is enough.
Dr. Allan Mishra, an orthopedic surgeon with Stanford Health Care who studies and educates students on sleep, said he liked the simplicity of Apple's approach and the focus on positive reinforcement rather than metrics alone. But he recommends that his students figure out the sleep relaxation strategies that work for them, whether it's to exercise or meditate, and consider trying out a sleep journal using pen and paper.
"In my opinion, the best way to track sleep is a sleep diary, and not an electronic device," he said.