How does it calculate restful vs light sleep?

[onysi]

Most mornings, I feel well rested but the band tells me that I only have 2 or 3 hours of restful sleep. Light sleep tho is like 4 hours. Is it measured by our heart or movement?

 

[dorelse]

Well, for starters, you're supposed to cycle through the sleep cycle, so don't get hung up on the light vs. restful so much, its a cycle, and should look like a city skyline. I'd like to know the how as well, but it should not be all 'Deep Sleep'...

 

[ven07]

might have to do with your heartbeat and pulse rhythm

 

[DroidUser42]

It's one of the great mysteries. As far as I know, MS hasn't released that information.

 

[Skippy07]

It's one of the great mysteries. As far as I know, MS hasn't released that information.

I understand Microsoft may have not release the information, but does anyone know, in general, how wrist worn fitness tracking devices are able to track sleep?

-Skippy

 

[kevin2577]

Most wrist wearables (and even some phone apps where you place your phone on the bed underneath the sheet use accelerometers to calculate restful vs. light sleep, with less movement during restful/deep sleep and traditionally more "tossing and turning" indicating light sleep.

These devices like Nike Fuelbands and Fitbits calculate your sleep this way. Newer devices that have heart rate sensors like the Fitbit Charge HR, MSFT Band, and most Basis devices combine accelerometer motion data with heart rate readings for improved accuracy.

 

[DroidUser42]

I'd like to know if there's any medial classification or if it's largely arbitrary.

Microsoft (and other health band devices) might want to step careful in this area, or they might end up like 23andMe who was ordered by the FDA to stop selling DNA analysis for medical purposes over accuracy issues.

 

[ven07]

I'd like to know if there's any medial classification or if it's largely arbitrary.

Microsoft (and other health band devices) might want to step careful in this area, or they might end up like 23andMe who was ordered by the FDA to stop selling DNA analysis for medical purposes over accuracy issues.

I didn't know that there was a company "23andMe" lol.. but it probably wouldn't be that easy to tell all of these companies to stop with this claim, as they could easily start pointing fingers at the others or say that the devices are merely there to give an indication and not a precise read

 

[DroidUser42]

I didn't know that there was a company "23andMe" lol.. but it probably wouldn't be that easy to tell all of these companies to stop with this claim, as they could easily start pointing fingers at the others or say that the devices are merely there to give an indication and not a precise read

I didn't expect anyone to. I provided the name so people could use their favorite search engine to find the details and see how much might apply here. It is worth nothing that while we get measurements, MS has been very quiet on any "actionable" information based on those results.

Who knows - maybe the "results" we'll get is to know where with stand with other band users. If we're in the 99th percentile for sleep, maybe we should do something about it.

 

[onlysublime]

This is probably the breakdown between NREM (non-rapid eye movement) sleep and REM (rapid eye movement) sleep.

Once you fall asleep, you get into NREM sleep. Deep sleep or slow wave sleep is one of the stages of NREM sleep. Then you transition to lighter sleep which is REM sleep. And then you go back to NREM sleep. And then back to REM sleep. And you keep alternating until you wake up.

NREM sleep is considered more restful and contains the deep sleep. If you try to wake up during your NREM sleep, it can be awfully hard to. You can feel really groggy.

Waking up during REM sleep is much easier and light sleepers who are easily awaken tend to have longer REM cycles.

It's why if you're setting your alarm clock, try to set it to wake you up during an REM cycle.

You need both REM and NREM in sufficient amounts. The thing to worry about is really how many times you wake up at night. If you wake up a lot at night (but don't realize it), you could have a problem like sleep apnea. Sleep apnea causes the body to "wake up" because the brain senses low oxygen or high carbon dioxide and tries to fix it by increasing breathing and other emergency measures to correct the problem. Sleep apnea can lead to insufficient sleeping leading to feeling tired during the day, increased blood pressure, personality changes, increased cardiovascular risk, etc.

 

[bobsentell]

This is probably the breakdown between NREM (non-rapid eye movement) sleep and REM (rapid eye movement) sleep.

Once you fall asleep, you get into NREM sleep. Deep sleep or slow wave sleep is one of the stages of NREM sleep. Then you transition to lighter sleep which is REM sleep. And then you go back to NREM sleep. And then back to REM sleep. And you keep alternating until you wake up.

NREM sleep is considered more restful and contains the deep sleep. If you try to wake up during your NREM sleep, it can be awfully hard to. You can feel really groggy.

Waking up during REM sleep is much easier and light sleepers who are easily awaken tend to have longer REM cycles.

It's why if you're setting your alarm clock, try to set it to wake you up during an REM cycle.

You need both REM and NREM in sufficient amounts. The thing to worry about is really how many times you wake up at night. If you wake up a lot at night (but don't realize it), you could have a problem like sleep apnea. Sleep apnea causes the body to "wake up" because the brain senses low oxygen or high carbon dioxide and tries to fix it by increasing breathing and other emergency measures to correct the problem. Sleep apnea can lead to insufficient sleeping leading to feeling tired during the day, increased blood pressure, personality changes, increased cardiovascular risk, etc.

Well, given the Band doesn't go over your eyes, I'm going to go with movement being the key. In REM, you are a dead body in terms of movement while in NREM, you will subconsciously move to get more comfortable. The Band only takes your pulse every once and a while. It could see your low pulse in combination of your lack of movement as confirmation of your REM sleep. If your pulse is higher, Band could tag that period as NREM.

As mentioned above, it is supposed to be an indicator. I'd attribute it to those home blood pressure testers. They provide you information but will never take the place of a doctor. If you have concerns about your sleep patterns and the Band shows you don't sleep well, go to a doctor who will do a proper sleep study.

 

[ven07]

I will stick to the explanation I have in my head.. It depends on how much you move at night, but that only goes for the simple pedometer devices like up24 or flex.. The newer devices with built in heart-rate monitors could also measure your heartbeat, which would give a pretty good idea whether or not you're restless

 

[onysi]

I had a nightmare around 3 am today. Once I was fully awoken, about 5 minutes later, I synced my band to check the status, and on the graph, it said I was awake at 2:55 am and before that I had a 20 minute light sleep. I thought that was interesting.

 

[ven07]

I had a nightmare around 3 am today. Once I was fully awoken, about 5 minutes later, I synced my band to check the status, and on the graph, it said I was awake at 2:55 am and before that I had a 20 minute light sleep. I thought that was interesting.

Nice.. Like I said.. The band can measure heart rate and mostly your heart will speed up during a nightmare (cuz none of them are pleasant ) and it then registers that as a restless period..

 

[mhc48]

@onlysublime, about how many times a night waking up would be an indication of sleep apnea?

 

[onlysublime]

there's no set number. a person with sleep apnea may be waking up hundreds of times a night without knowing it. a person with sleep apnea may stop breathing 300 times a night.

you really need to undergo a sleep study to properly diagnose it. the easiest indicator of course is severe snoring. now snoring due to sleep apnea is different than regular snoring. so you can't automatically assuming snoring is due to sleep apnea. sleep apnea snoring will often have choking/gasping or abrupt episodes. so in sleep apnea, you may have snoring, then silence, then choking/gasping, then silence, then snoring. if you don't have anyone around to hear your breathing, an indicator is you're always tired throughout the day even though you think you got plenty of hours of sleep.

Now, sleep researchers look only at brain waves via EEG to determine stage of sleep. Claims by fitness trackers of using heart rate, accelerometers, etc. aren't substantiated. And movement is the worst indicator for sleep. You can move the same amount whether you're in deep sleep or lighter sleep.

I have no idea how the Microsoft Band makes its calculations. And really any fitness band's claim is kind of dubious according to the sleep experts (sleep experts will tell you that correlating heart rate to brain waves is dubious right now). As with any of the fitness sensors out there, don't use the data as definitive answers. It's all more for guidelines for healthy living. That's why whenever I read about how accurate this is or that is, it has to all be taken with a grain of salt.

If you're curious, there's a guy that wrote an article wearing a bunch of devices during one night's sleep and these were the results:

 

[DroidUser42]

@onlysublime - it may be hard to define "normal", but I'm wondering if there's any signs that we should be alert for that signify "abnormal" and needs to be looked at?

 

[Michael Evanchik]

how in the world does it know when you dream. you would need to read brain waves

 

[SiriuS_r3d]

Well some one has already tried to compare it... a good read.. hope it clears some doubts..

Kodierer [Coder]: ZzzZzz - Microsoft Band Sleep Tracking in the Testbed

 

[DroidUser42]

Well some one has already tried to compare it... a good read.. hope it clears some doubts..

Kodierer [Coder]: ZzzZzz - Microsoft Band Sleep Tracking in the Testbed

Interesting. Considering the Band's lack of sophisticated sensors and its low sampling rate, I'm not surprised by some error. And at this point I'm not sure as actual numbers are meaningful. I'm more interested in trends and where I stand with where I should be. And the Band did indicate improved sleep the second night - which to me is the most important.

One thing that's puzzling: The band shows "Actual Sleep" as a simple sum of "Light" and "Restful". While the lab's results do NOT total up that way. So I'm not sure as I'd compare the two for that line item.