Fitbit Estimated Oxygen Variation: We Explain Spo2 Sleep Apnea And Blood Oxygen
In January 2020 Fitbit turned on its long awaited blood oxygen detection feature. Since 2017 its been packing an SpO2 sensor into its leading devices, but hasnt used the data. Until now.
Blood oxygen can be used to detect sleep conditions such as sleep apnea, and offer a better analysis of whats going on with our bodies in those lost hours.
But Fitbits Estimated Oxygen Variation data needs a little explanation. We spoke to Dr. Conor Heneghan, Fitbits Lead Sleep Research Scientist for everything you need to know.
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What Is The Fitbit Sleep Score
The Fitbit sleep tracker algorithm will combine several key sleep elements based on:
- Duration: The higher the number of hours slept, the higher the score. The recommended number of sleep hours is between 7 and 8 hours. You will get extra points if you reach this sleeping range.
- Quality: The sleep cycle is divided into phases of light, deep, and Rapid Eyes Movements . Deep and REM sleep phases are the best for recovery, and the longest time spent in these two cycles, the higher the score.
- Restoration: The higher the score, the more restful the sleep was. The sleep tracking function will measure the heart rate and movements to define the state of relation, hence the sleep quality and restoration. The sleep pattern, time spent in light or deep sleep, will be analyzed and correlated with the heart rhythm to extract the average sleeping heart rate. This information will be essential as a higher restoration score will be assigned if the sleeping heart rate is lower than the average day heart rate.
The overall sleep score divides into:
- Excellent: 90-100
Users voiced their disappointment when Fitbit decided to make some of the sleep features part of their Premium package.
The Free App. still allows checking the Deep & REM sleep stages, but the analyses of sleep duration and sleeping heart rate & restlessness are part of the paid subscription.
Your Heart Rate Is The Key To Smarter Sleep Stages Heres Why
If youve been using a Fitbit tracker to monitor your sleep, then you know how important movement is to signaling when you fall asleep, wake up, or stir. But in order to determine your sleep stageshow long you spend in light, deep, and Rapid Eye Movement sleepmovement alone is not enough.
During sleep studies, most sleep stages are scored based on brain waves, says Michael Grandner, MD, director of the Sleep and Health Research Program at the University of Arizona in Tucson and a Fitbit sleep consultant. Except during REM sleep when doctors are also looking for eye movements and a lack of muscle activity.
In other words, you cant determine light or deep sleep based on movement alone. You need another signal, says Grandner. You need something else that is going on in the body that differentiates REM from other stages of sleep.
So whats that second signal? Heres a hint: Its something many Fitbit trackers can already trackheart rate!
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What To Check When You Wake Up
When you rise bright and refreshed in the morning , your Fitbit will register that youre awake and stop tracking your sleep. On the apps main screen, you can scroll down to see how much sleep you got overnight, together with a breakdown of the different stagesREM, light, and deep. Tap this to see more details.
Youll then get a full chart showing what times you were in which stages of sleep, helping you spot particular spells of restlessness. You can also look back on your 30-day averages, as well as the common ranges for people who match your gender and age. If your smartwatch can measure blood oxygen saturation, youll see how this fluctuated over the course of the night too.
The Fitbit rounds up several metricsheart rate, movement, stages of sleepinto one overall sleep score for the night. It essentially rates the quality of your sleep when all of its measurements have been taken into consideration. Your sleep score will be broken down into different sections, including restorationa measure of how recharged your body should be the next day.
All You Need To Know About Fitbit Sleep Score
Smartwatches are now getting really smart and offer numerous features to track your vitals while active and at night while sleeping.
Fitbit Sleep Score is different from a simple analysis of sleep cycles based on the motion analysis. It makes the most of the Heart Rate monitor and blood oxygen sensor.
Introduced in 2019, the sleep score is now available for most of the Fitbit range, including the Fitbit Luxe, Fitbit Versa, Versa 2, Versa Lite, Sense, Ionic, Charge 4, Inspire 2, and Fitbit Inspire HR.
It is somehow important to note that users recently complained about issues while collecting sleep score data, especially when using the Fitbit Charge 4. Fitbit acknowledged the issue and is working on fixing it. With no timeline being released, before considering buying a Fitbit Charge 4 for sleep tracking, we recommend that you check that the problems are solved, and a software update is available.
In this article, we will go through the Sleep Score app. and check how to make the most of the features that may well change the quality of your sleep. We spend one-third of our life sleeping, so our rest certainly deserves a smart sleep tracker.
Are you ready and fully awake? So, lets check on how to enjoy a restful Zzz.
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What Happens If I Dont See Any Sleep Stages
There are some reasons why you might not see the report of your sleep stages and they are:
- The position you slept in prevented your Fitbit from getting a consistent measure of your heart rate or you ended up wearing it too loosely. To improve the results, wear your device higher on your wrist when possible and it should feel secure but not too tight.
- If you have used the Begin Sleep Now option on the app instead of simply wearing your device when going to bed, it may show some inaccurate details.
- If you have slept less than three hours of if your devices battery is critically low, the data may not be reflected.
For additional information on your recorded sleep pattern, you can tap on the sleep record that appears on the sleep pattern.
Setting A Sleep Schedule And Reminders To Stick To It
One of the things I really liked during the month is the option to set a sleep goal / schedule and then get reminders to stick to it.
In the App settings, you can input your target sleep schedule. Since Im a bit of a night owl, I went with bedtime at 12:30 a.m. and wake up at 8:30 a.m.
You can limit the days for your schedule if you like, but I know I personally benefit from a regular 7 day a week pattern.
Following that, you can ask for a reminder to help you wind down for sleep, which I set an hour before at 11:30 p.m.
Every night I then received both a notification on my phone and a vibrating reminder on my wrist to encourage me to stick to that bedtime. And in theory, start winding down by putting aside any late night work, and reading a book or relaxing rather than watching the next episode of my favorite TV series.
I found this a very helpful tool, and one which I can see actually benefiting people. And to help motivate you even more, if you manage to hit your target youll get a green star on the App the next morning.
So lets take a look at the App data and how useful it might be.
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New Fitbit Features Deliver Data Previously Only Available Through A Sleep Lab
Sleep, slumber, shuteye, Zzzs. Call it what you will, just make sure you stay on top of it. How muchand what kind ofsleep you get can affect your appetite, energy, weight, and recovery, not to mention protect against heart disease, diabetes, and cognitive decline. In other words, its pretty critical to your health and well-being. Thats why Fitbit is taking sleep tracking to the next level with Sleep Stages and Sleep Insights, two innovative new features that give you access to information previously only accessible in a sleep lab.
Delete Or Edit Your Sleep Log
For days with missing scores, edit your sleep log by manually re-entering your sleep & wake times.
If your Fitbit is not showing your sleep scores for any day, try deleting your most recent sleep log and see if you get a sleep score the next morning.
Removing or changing this data often helps retrieve your missing data & sleep score.
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How To View Sleep Tracking Data On The Watch
There’s really nothing to tracking your sleep with a Fitbit tracker beyond simply setting up the app and wearing the device to sleep. Just be mindful of your band since improper placement can effect the tracking. As long as it’s secure on your wrist and the battery is fully charged, you’ll get a reading automatically. Then, have fun exploring all of the details you can get from the app, including tips and advice as well.
Sleep Stages: What Are They
Your body goes through several sleep stages each night while you sleep. Each one lasts about 90 minutes before you cycle through to the next one. During each stage of the sleep cycle you alternate between deep sleep and light sleep.
When you arent in Rapid Eye Movement sleep, youll alternate between the two Non-Rapid Eye Movement stages. You spend more time in deep sleep during the beginning of the night.
When you enter into REM sleep, you experience vivid dreams . The amount of time you spend in REM sleep typically increases as the night goes on. Earlier in the night your REM stages are brief, but when you get closer to waking up youll spend a lot more time in the vivid dreaming stage of sleep.
Read Also: When Does Rem Sleep Occur In The Sleep Cycle
The Limitations Of Sleep Tracking
Even though Fitbit is a brilliant gadget and really useful as a health tool, it does have certain limitations. For example, it wont automatically keep track of naps shorter than one hour, since thats the default resting period that will activate the automated readings. If youre adept of short naps and you want to capture all your sleep stats, you will have to remember to activate sleep mode manually whenever you lie down.
Can The Sleep Score Provide Insights On Sleep Apnea
Tracking heart rate, movements and HRV are critical features for identifying the sleep stages, but sleep apnea detection goes one step further. During sleep apnea, sleepers will stop breathing, inducing a drop in the blood oxygen saturation levels.
Some recent Fitbit models do include a SpO2 sensor meaning that the technology s ready to expand the capabilities of the Sleep Score and include the much-needed feature of sleep apnea detection and quantification.
Smartwatches are a complex mix of hardware, software, and algorithms that rely more on machine learning. The excellent point is that once the technology is validated, a simple software update is the only thing needed to add extra-functionalities.
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Fitbit Sleep Stages Review: A Strong Sleep Tracker With Plenty Of Promise
Sleep tracking often feels like a white whale for many fitness-tracking companiesoften, even popular fitness trackers are inaccurate at best. For a long time, the only way to get truly accurate sleep tracking was by shelling out for a dedicated sleep tracker like the Withings Aura, and even then theyre not perfect.
With Sleep Stages, Fitbit claims that its sleep tracking has taken a major step forward and can provide information that youd normally only be able to get from expensive sleep studies, such as accurate records of how long you spend in light sleep, deep sleep, and REM. If you own a Charge 2, Blaze, or the brand-new Alta HR, you can take advantage of the Sleep Stages. Fitbit provided an Alta HR so I could test the effectiveness of Sleep Stages.
First, a word about the Alta HR: I think its an excellent all-around fitness tracker. Its compact, visually appealing, and reinforces Fitbits reputation for accurate and useful fitness tracking. The small LCD screen is still large enough to tell time and provide text notifications, and thankfully the battery lasts long enough so that you dont have to worry about charging daily . If youre looking for a new fitness tracker that does all of the basics, its hard to say no to the Alta HR.
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Evaluation Of Sleep Parameters Estimated By Fitbit Models Versus Actigraphy
No published study assessed performance of sleep-staging Fitbit models relative to actigraphy in estimating sleep parameters. In contrast, 7 studies investigated the accuracy of nonsleep-staging Fitbit models relative to actigraphy 1 of them involved two different actigraph devices , and another 1 included two different samples: good sleepers and poor sleepers . Among the total of seven potential comparisons, Fitbit significantly overestimated TST in five of them by 24.1-74 minutes, while in two comparisons , it was nonsignificantly overestimated. In a total of four comparisons , Fitbit significantly overestimated SE by 1.1%-7.0%. Among a total of five comparisons, Fitbit significantly underestimated WASO in four of them by 16-32 minutes, while in one , it was nonsignificantly underestimated. Only 1 study evaluated SOL, finding an 11.5-minute significant overestimation by Fitbit.
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How Does Your Fitness Tracker Know When Youre Asleep
Sleep tracking is a big part of what we do at Exist. We currently sync sleep data from Fitbit, Jawbone UP, Misfit, Nokia Health, Apple Health, and Google Fit.
We use that sleep data to look for trends and insights in your behaviour, by adding to it data from your Twitter, Facebook, Swarm, and Instagram accounts, productivity data from RescueTime, GitHub, Gmail, your calender, and Todoist, the music you listen to from last.fm, plus your weight, weather, exercise, nutrition, and location data.
I dived into some research to work out whatâs going on when you set your Jawbone UP or Fitbit to sleep mode. Both devices use accelerometers to track your movements, including the speed and direction of your motion. This is how they track your activity during the day, and how they tell when youâre asleep.
When you set your Fitbit or Jawbone UP device to âsleep mode,â it monitors your movements. When you sync your device the next morning, the software translates those movements into sleep data. If youâve ever edited your sleep times the next morning, youâll have seen a glimpse into how this worksdata about your movement during âawakeâ time gets re-analysed when you tell the software you were actually asleep then, and you then see it charted as sleep data.
This method of using a device to track movements in order to measure sleep is called actigraphy.
Level Of Agreement And Correlations
– show the Bland-Altman plots comparing Fitbit Charge 2 with the medical device. Device discrepancies for sleep outcomes are plotted as a function of the medical outcomes for each individual. The mean bias ranged from 0% to approximately 60% . No more than 2 participants were situated outside the lower limit of agreement or the upper limit of agreement.
Bland-Altman plots assessing the level and limits of agreement between Fitbit Charge 2 and medical device on the transition probabilities from rapid eye movement sleep to light sleep, from light sleep to REM sleep, and the probability of staying in REM sleep. The dashed line in the middle represents the mean difference, whereas the upper and lower dashed lines represent the upper limit of agreement and the lower limit of agreement.
Bland-Altman plots assessing the level and limits of agreement between Fitbit Charge 2 and medical device on the transition probabilities from wake to light sleep, from wake to rapid eye movement sleep, from wake to deep sleep, from light sleep to wake, from light sleep to deep sleep, from deep sleep to wake, from deep sleep to light sleep, from deep sleep to REM sleep, from REM sleep to wake, and from REM sleep to deep sleep.
Bland-Altman plots assessing the level and limits of agreement between Fitbit Charge 2 and medical device on the probability of staying in light sleep, in deep sleep, and in wake.
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