I have been using apps on my iPhone and Apple Watch for several years to track my sleep. I have old models iPhone 11 and Watch 4 but they both still work well and can run the latest updates as far as I know.
I use Sleep Cycle and Pilllow and also Apple’s own sleep tracker in Health.
All three calculate the four stages of sleep, Awake, REM (dreaming), Light and Deep sleep proving a time period for each in hours & minutes plus a percentage of total sleep.
HOWEVER, the three apps provide different interpretations of my sleep pattern each night so I wonder which is the most accurate or right/wrong.
I appreciate that it is difficult to assess someone’s sleep stages so the three apps probably all use different measurements and assumptions. Pilllow in particular suggests much longer periods of REM sleep than the others while Apple Sleep suggests much longer periods of “Core” sleep.
What I would like to know is if one app is better or more accurate than the others. Has anyone done any sort of experiments comparing the results with a sleep laboratory of some kind (maybe in a university?).
Does anyone know if anyone has done research on this please?
I don’t know of any research done on this, which would likely require test subjects hooked up to EEG machines in order to track brain waves as well as the data the watch collects of movement and heart rate. I imagine that Apple did this before they started supporting sleep reporting, probably creating a model that best approximated the real sleep patterns detected. But I haven’t found any articles that say this.
I used AutoSleep for years (going back to 2017) but on January 1 I switched to Sleep++. AutoSleep kept mistaking quiet periods during the day for sleep, which so far Sleep++ has not done. But Sleep++ does an excellent job of detecting sleep and waking times from my observance over the last four weeks.
My advice is to pick one solution and ignore the others. To me the data is most valuable when it shows how the app determines any pattern changes for any of the sleep cycles. So if you chose to use Apple’s data, just look at Apple’s data.
FWIW, before I was diagnosed with sleep apnea, my doctor prescribed an in-home sleep study.
I was sent a small device to sit on my nightstand. The sensors were:
A pulse-ox probe on a finger tip
A fabric strap across my chest (I assume to measure respiration)
A silicone nosepiece with a microphone to detect snoring.
Nothing resembling an EEG was used. I wore the sensors when going to sleep for three nights, then mailed the entire kit back to the lab, who downloaded its sensor data and send a report to my doctor.
Right, I know a few people who have done sleep studies for sleep apnea. But I think in order to quantify sleep into REM, core, awake, etc., you really need to scan the brain to be 100% accurate.
I currently don’t have a watch that supports the new sleep apnea detection but I’m relatively sure that I don’t suffer from it. My watch never detects periods of no respiration, heart rate spikes, etc., during sleep, and I generally tend to feel rested when I wake after adequate sleep.
From what I can tell from Sleep++ so far it uses the stock watchOS sleep categorization - awake, REM, core, and deep.
By the way I am sending this as I fly over the Caribbean Sea and toward the Atlantic. For all that people gripe about modern technology, this to me is basically miraculous.
But you may be able to get a “good enough” reading from other sources.
For the month or so where I owned a Sleep Number bed (a story to be told at another time), its mobile app reported all kinds of sleep statistics including times awake vs. asleep and light vs. deep sleep. Since nobody was wearing sensors, I assume it was computing something based on feedback (pressure changes and vibration) received through the air hoses that keep the mattress inflated.
Of course, I have no clue how accurate those readings were. I didn’t care enough to bother to find out.
You might want to read this. It matches my experience of tracking sleep with the apple watch because of middle of the night insomnia. the insomnia kept getting worse and worse, but once I stopped tracking (before I found the article) everything improved greatly.
“Sleep perfectionists: the exhausting rise of orthosomnia”
"Dr Neil Stanley, the author of How to Sleep Well, has been working in the field of sleep research for 42 years, starting out at the neurosciences division of the RAF. He sighs when I ask him to explain how most devices analyse our shuteye. “These things can just about measure how much sleep you’ve had, and how long it took you to get there,” he says. “But the only accurate way of distinguishing between light sleep, deep sleep and REM sleep is by observing the brain.” He mentions that while one study showed that sleep trackers are now “reasonably accurate”, some of the claims made are questionable.
"But Stanley also wants to raise a more fundamental question. “I’ve spent my career hooking people up to monitors in spaces designed to be the finest bedrooms on the planet. I’ve sat there watching the squiggly lines that measure the different stages of sleep. And, to be honest, it doesn’t mean a thing. Because what even the most accurate data cannot do is influence you to sleep more hours. So, for the general public, what’s the point?”