Three years ago, I read Why We Sleep. Hard to remember another book that had a more immediate impact on my daily habits – from changing when I drank caffeine, to being more disciplined about my bedtime, to being more aware of not only the quantity of sleep, but the quality of that sleep.
Shortly after, I got a Motiv ring as a sleep tracker; for the last two years I’ve used an Oura ring (v2) to gather data about my sleep. Several observations from my own sleep data reinforced a number of recommendations made in Why We Sleep:
- Alcohol has a huge impact on my resting heart rate over night. Each drink I have adds 3-5 beats per minute to my resting heart rate overnight. Two or more drinks raise my resting heart rate by as much as 20%, leading to as many as 4500 extra heartbeats per night.
- Bedtime and length of sleep, not surprisingly, matter. In Oura’s case, it assigns both a “sleep score” and a “readiness score” to evaluate the quality of your night’s sleep. After alcohol, these two contributors were the biggest drivers of how well I slept, and how rested I’d be in the morning.
- Exercise – or lack thereof – is meaningfully connected to how well I sleep. The more I exercise, the lower my resting heart rate. The lower my resting heart rate, the deeper my sleep. The deeper my sleep (and the longer I sleep), the more rested I am the next morning.
Last year, I moved back to iOS after a decade of being a committed Android user. Shortly after moving to an iPhone, I added an Apple Watch – among other things, I loved how much health-related data it captured, as well as how well integrated it was into the tools I was already using (a Withings smart scale and my Oura ring, among others). But since I wore an Oura ring, I didn’t bother exploring the watch’s sleep tracking.
After I twice “lost” a night’s sleep data due to the ring’s battery level being too low (though the ring is supposed to go 5+ days between charges, my ring’s battery was starting to flag after just over 3 days between charges, and I wasn’t remembering to charge as often as the ring clearly needed), I decided to see what the Apple Watch could do. Sleep tracking is one of the benefits Apple touts for the Apple Watch; for non-Health uses, I’ve enjoyed its ability to let me unlock my phone while wearing a mask, and the ability to approve 1Password prompts without taking my hands off the keyboard is pretty slick too.
Wearing the phone (update: watch, LOL) to bed proved to not be at all intrusive or uncomfortable, which was my first concern. The first morning, I was pleasantly surprised to realize that my phone alarm used haptic feedback on my wrist instead of an audible alarm on my phone: waking up was less abrupt, and my wife was able to stay asleep while I went downstairs to ride the Peloton. Forget about the health data / benefits, that’s a huge upgrade that probably is enough to justify wearing the watch to bed all by itself!
The first night, Apple Health properly captured how much time I’d slept, and the data the watch tracked – including resting heart rate – was properly attributed in its relevant category. But I missed the aggregated view that gave an overall report about the sleep – I had to hunt around in the Apple Health app to find the data that mattered.
I saw a reference to AutoSleep ($4.99) in an article about sleep tracking on iOS; after installing it, I was immediately presented with the aggregated view I’d been looking for in Apple Health:
That’s from last night’s sleep; in addition to aggregating key metrics (time asleep, sleep stage, respiration rate, resting heart rate), it uses the familiar rings UI convention (borrowed from Apple Health) to give a visual snapshot of the prior night’s sleep. (For those wondering: yes, I had two cocktails last night. Otherwise I would expect my resting heart rate to be in the low- to mid-50s. They were tasty, but… oof.)
One data point entirely new to me, which I think I’m going to love: “sleep bank.” I stayed up late last night watching a show with my wife and daughter, and didn’t go to bed until just after midnight. As a result, I got less than my target 7.5 hours of sleep – leaving me in “sleep debt”. Fortunately, the night before, I got a bit more than 7.5 hours – but across the two nights, AutoSleep calculated that I remain in debt, which I should be mindful of tonight / tomorrow night / etc. to try and catch up. I love the idea of looking over a longer time horizon than just one day to try and influence how I think about the day(s) ahead, versus simply looking back at what happened last night.
And that, I think, is where I think Apple Watch / AutoSleep tracking is going to come out ahead of the Oura ring for me. Battery performance aside, the Oura ring was in my experience very good about reporting on past data, but less effective at provoking specific changes to my behavior going forward. It was outstanding at identifying causal effects (alcohol, bedtime, etc.); less effective at influencing decisions going forward. AutoSleep’s sleep debt seems like it will be a more useful and actionable interpretation of the data, that will meaningfully influence how I think about future decisions (when to go to bed, when to set my alarm, whether to have that additional drink).
PS: though I thoroughly benefitted from reading Why We Sleep, there are considerable questions around some of the data core to the premise of the book, best represented here. From my personal experience, the book motivated me to both learn more about my sleep and the contributors to the quality of that sleep; three years later, I’m healthier – in part thanks to that motivation. YMMV.