Apple Watch detecting Sleep Apnea - Myth or Truth?


Sleep apnea is a condition that causes a person to stop breathing suddenly while sleeping, for short periods of time, leading to oxygen deprivation and sleep disruptions. It often presents as loud snoring, choking or gasping for breath during sleep. Sleep apnea is a serious medical condition with major health consequences including risk of hypertension, cardiac arrythmias, heart disease and even stroke. It is currently one of the biggest public health challenges, where over 80 percent of people with this condition are going undiagnosed.


A recent market announcement by Apple Company, that their smart watch, Apple Watch Series 10 is able to detect sleep apnea seems to have raised a flurry of curiosity both amongst users and amongst Sleep Specialists. So, let’s take a look at this technology of detecting sleep apnea and its applicability in real life


Firstly, Apple Watch series 10 has introduced a new metric called Breathing Disturbances. Breathing patterns are analysed based on the sleeper’s movements. Essentially, this Apple Watch uses accelometer technology to assess small wrist movements, that could potentially be associated with interruptions in normal respiratory patterns. The Breathing Disturbances metrics works on the assumption that body movements are caused by disturbances in breathing patterns and therefore, these movements may be associated with sleep apnea. Apple Watch collects 30 days of data and then analyses it. Users will see elevated or not elevated readings under breathing disturbances section of Apple’s Health App, alerting users if they have signs of moderate to severe apnea.


There are a few catch points here. First, there is no clarity on how this metric and their AI algorithms are differentiating between normal nocturnal body movement, movements due to other causes including sleep related movement disorders and movements due to sleep apnea. Apple does claim that it’s Sleep Apnea detection technology has been validated in a study that was “unprecedented” in size for sleep apnea technology. We need to be aware that an inherent limitation with AI and advanced machine learning is that, it is only as good as the data that goes in. As of now, there is no clarity from Apple about their research and the data quality that has been used for their algorithms


Second point to note is Apple Watch currently does not have the ability to analyse oxygen saturation data and does not include it in their sleep apnea detection data. This would also be a major handicap, if it is unable to detect hypoxia. Hypoxia is an important physiological parameter that is needed, to properly assess sleep related breathing disorders. Hopefully, changes to include oxygen saturation data are in the pipeline.


Third, the report in Apple Watch seems to report only on moderate to severe sleep apnea and not on mild sleep apnea. This can easily lead to missing out on many mild cases which defeats the purpose of early screening.


Incidentally, currently, other smart watches like Samsung Galaxy, Google Pixel Watch also have a market claim, in Sleep Apnea Detection. Samsung, similarly, uses sensors in the watch that look for potential signs of breathing disturbances. Google Pixel watch uses oxygen saturation.


A question arises, with respect to sleep apnea detection, how do these smart watches compare to other consumer sleep technology devices that propose to diagnose or detect sleep apnea?


Currently, there are various consumer sleep wearables that report on sleep apnea. They use varying parameters in their data analysis, like oxygen saturation, peripheral arterial tone, Photoplethysmography, heart rate, heart rate variability, respiratory effort or rate, acoustics, actigraphy etc detect and quantify sleep apnea. Each of these have their advantages and limitations and the topic is too vast to address in this article. I will try to address it in a follow up article.


But a more important question is, how do consumer grade sleep wearables or nearables, that report on sleep apnea detection compare to validated medical grade sleep studies? As we know, data derived from these wearables is through indirect physiological information and this data is computed using AI or advanced machine learning algorithms to make an assumption of Sleep Apnea.


In comparison, validated medical grade sleep studies use more correctly placed sensors to collect accurate data. For example a nasal sensor, is placed directly underneath the nose to accurately measure breath and airflow disturbances, similarly brain sensors are place on head to accurately record brain wave activity during sleep. Such studies helps us in specific diagnoses like type of sleep apneas, differentiate between hypopneas and apneas, oxygen desaturations, accurate sleep staging and sleep efficiency, cortical arousals during sleep, limb movements, bruxism. This amount of detailed information is currently not accessible through consumer sleep wearable devices


Next in consideration is about FDA clearance or approval of these sleep apnea detection wearables. As of this date Sept 12th 2024, none of these devices have FDA approval to be used as medical grade devices for diagnosis of sleep apnea.


So, coming back to the original question, is the sleep apnea detection data collected by an Apple Watch meant for medical use? The answer is, reports derived from these devices are not sufficient and cannot replace proper diagnostic sleep studies and treatment by a Sleep Specialist.


But it’s not all bad news for the Apple Watch series 10. These consumer level sleep health devices or sleep apps will empower the user to get an idea what is happening to their sleep and body when they are asleep. Sleep apnea detection devices will help raise awareness and prompt people to seek timely medical help, before multiple comorbid health conditions set in. Apart for sleep apnea detection, these sleep wearables will motivate an user to track their sleep and help them achieve optimal quality and quality of sleep. This in itself will sway the pendulum towards better individual and public health in our communities.


Prospects are definitely bright in sleep technology industry and it is possible that at some time in future, sleep diagnostics can be done with simple gadgets like smart watches. But if the consumer sleep wearables industry were to ask “are we there yet” the answer would be “not yet, but maybe soon “.


Ending this with a word of caution, reports generated in consumer sleep wearables is currently geared only for adults and these are not applicable for children.


Secondly, if you do experience any symptoms of excessive daytime sleepiness, fatigue, brain fog, snoring, dry mouth on wakening, disturbed and unrefreshed sleep and yet if your sleep wearable does not detect sleep apnea. DO NOT IGNORE your symptoms. Do seek a consultation with us at NK’s Snoring and Sleep Apnea Centre. + 91 6366909091 Good Sleep Leads to Good health.