Sleep trackers have been around for a while now, and I know that many people find real value in them. For just over a month, I tried using Sleep++, a free app by developer David Smith who has created lots of useful apps (including Activity++, an app that I enjoy using to keep track of my progress over time with the Apple Watch activity rings). I feared that wearing my Apple Watch overnight (and thus not charging it during the night) would mean that my Apple Watch would run out of power during the day, but I thought that the value of monitoring my sleep might be worth it. It turns out that I was wrong on both counts. Power wasn't a problem at all; it doesn't take very long to give an Apple Watch enough power to last all day. On the other hand, and to my surprise, I didn't really see any value to monitoring my sleep activity.
Finding time to charge
I'll start with the good news. It turns out that it isn't necessary to charge an Apple Watch all night to keep it powered during the day. My tests were with a 42mm Apple Watch (which has a larger battery than the 38mm version), and I have the newest Series 2 Apple Watch (which has better battery life than the original Apple Watch). If you are using a different model, you might not have the same experience that I did. But I found that if I took off my Apple Watch after I woke up and charged it while I was showering and getting ready for work, that small amount of time gave me enough power to go all day long. Sometimes at night I would also charge it for a little bit while getting ready to go to bed just to ensure that I really did get enough charge. But with those one or two charging periods during the day, I was able to wear my Apple Watch all night long, so that Sleep++ could monitor my sleep, and I never had a problem with the Apple Watch running out of power during the day.
Using the Sleep++ app
Before using the Sleep++ app, I recommend that you put on a comfortable Apple Watch band. I love my Milanese Loop band during the day, but at night I found a Sport Band much more comfortable. (The Woven Nylon Band is also pretty comfortable at night.)
Next, when you are ready to go to sleep, start the Sleep++ app. The bottom of the screen will show data from your lats measured sleep. At the top of the screen, press the "Start Sleeping" button. Now you can go to sleep.
When you wake up in the morning, press the Stop Sleeping button at the top of the screen. The app will then take a few seconds to analyze your sleep from the night before, and will then send the sleep data to the Sleep++ iPhone app. In that app, you can see data on your sleep, including what time you went to sleep and what time you woke up. Darker blue bars indicate times that you were likely in a deeper sleep — or more specifically, the times that you didn't move your arm very much. Lighter blue bars indicate times that you were more restless. And if you get up out of bed at night, such as when nature calls, there is a skinny light blue bar to show you that.
Of course, you might not go to sleep exactly when you press the start button, and you might wake up before you remember to press the stop button. Thus, the app gives you the option to trim the start and stop times so that the data is more accurate.
The app stores your sleep data in the Sleep++ app so that you can go back and look at the sleep records for prior nights. And the app can also share that sleep data with the Health app, which could be useful not only because it keeps the sleep data in the same place where other health-related data is stored, but also because it makes it possible for other apps to access and use that sleep data.
A setting change every night and every morning
One thing that I did not like about using Sleep++ is that I found that for the app to be most useful, I needed to make an important change in the Apple Watch's Settings app every night. I needed to go into Settings -> General -> Wake Screen and then turn off "Wake Screen on Wrist Raise." When that setting is turned on, it was easy for the Apple Watch screen to turn on during the night. And if the screen turned on, it was possible to touch the screen to interact it with — even if I was sleeping and doing so without realizing it. I had two different nights when the Sleep++ app stopped recording my sleep in the middle of the night, apparently because I moved my wrist and the screen turned on, and then I must have touched the screen on the "Stop Sleep" button even though it was all unintentional because I was still sleeping.
Another reason to turn this setting off before using the app at night is it prevents the screen from coming on and creating light while you are moving your arm. I found that light distracting as I was trying to go to sleep. And of course having the light come on while you are sleeping is a waste of battery power, so turning this off every night gave me the best battery results too. But unfortunately, that meant that I had to go back into Settings to turn the function back on every morning because, during the day, I like being able to just raise my wrist to have the Apple Watch screen turn on.
It's not the fault of Sleep++ that I had to go into the Settings app every night and every morning to make this change. I'm sure that if there was a way for the Sleep++ app to do it automatically, it would do so. Even so, I found it annoying to have to make this change.
So what's the point?
My primary complaint about this app is that I don't really see the point. What good is it to see that I slept more one night versus another night? And seeing that I was more restless one night and less restless another night was somewhat interesting, but again, I don't quite get what to do with this information.
I see people suggesting online that if you monitor when you have a good night's sleep and correlate that with other activity in your life, including diet, you can learn to make changes in your lifestyle to get a better night's sleep every night. I suppose that makes some sense, but there are enough differences between my activity and diet every day that I wasn't able to discern any patterns after using this app for a month. And I see that at least some doctors have also questioned the value of this information.
For me, it was vaguely interesting to use this app for a month, but ultimately I didn't see any real value in it.
What would Apple do?
There is speculation that Apple will release its own Apple Watch sleep app in the future, perhaps in connection with a software or hardware update to the Apple Watch which improves battery life even more. Unlike Sleep++, an app from Apple could do things like turn off the Wake Screen on Wrist Rise automatically. And maybe Apple could even find more interesting ways to measure sleep data. David Smith himself recently wrote about the possibility that Apple could release its own app, making it necessary for Smith to find some other way to make Sleep++ provide value, such as better tools for analyzing data.
I'm glad that I tried Sleep++ for a month. It was interesting to see how an app like this works. And if Apple ever releases its own sleep tracking app, I may try this experiment again to see what I think. But for now, I just don't see much value in collecting sleep data with Sleep++. Having said that, if you own an Apple Watch and you do see a value in monitoring and recording your own sleep patterns, Sleep++ is worth checking out. It is free, it works, and you can use it without having your Apple Watch run out of power by just finding a small slice of time once or twice a day to charge the Apple Watch.