Garmin Forerunner Sleep Tracking: How Accurate Is It?

Sleep tracking is a popular feature of wearable devices, and Garmin's smartwatches and fitness trackers are no exception. The company has been enhancing its sleep-tracking capabilities over the years, with the introduction of Advanced Sleep Monitoring in 2018 and the more recent Firstbeat Sleep Tracking. While these features provide insights into sleep time and quality, questions have been raised about their accuracy. Some users have reported inconsistencies in Garmin's sleep data, with devices sometimes registering reading or relaxation time as sleep. In addition, there are concerns about the accuracy of REM sleep detection and the differentiation between light and deep sleep stages. Research and user experiences suggest that Garmin's sleep tracking may not be as reliable as that of competitors like Fitbit and Oura. However, it's important to recognize that no device is 100% accurate, and sleep tracking can still provide valuable insights into sleep patterns and potential issues.

Garmin Forerunner 945 sleep tracking accuracy

The accuracy of the sleep tracking feature of the Garmin Forerunner 945 has been called into question by several users. Many users have complained that the device is inaccurate in tracking sleep patterns, with some stating that it only identifies a few minutes of awake time and others claiming that it detects REM sleep when they are awake. Some users have also pointed out that the device does not track naps.

Garmin Forerunner 945 uses actigraphy to estimate sleep stages, which relies solely on movement detection and does not adequately incorporate other data like heart rate variability (HRV) or heart rate (HR). This has led to concerns about the accuracy of the device's sleep metrics.

In response to these concerns, Garmin announced Advanced Sleep Monitoring in June 2019, which was developed against truth data generated by a clinical device. The feature is the result of a sleep study conducted under the supervision of Dr. Suzanne Stevens, a renowned expert in sleep medicine. The study concluded that Garmin wearables with Advanced Sleep Monitoring provide a valid method to estimate sleep stages, offering invaluable insights into sleep hygiene and patterns.

Despite these improvements, some users still express dissatisfaction with the accuracy of the Garmin Forerunner 945's sleep tracking. They compare it to other devices like Fitbit, Oura Ring, and Jawbone bands, claiming that these alternatives offer more precise sleep tracking capabilities.

It is worth noting that the accuracy of sleep tracking devices can be influenced by various factors, such as loose straps, skin tone, and hair, which may contribute to discrepancies in the data. While these devices provide valuable insights, it is recommended to use them as a guideline rather than relying solely on their measurements.

Comparison with Fitbit

The accuracy of sleep tracking devices varies across brands and models. A 2021 study published in the journal Nature and Science of Sleep found that most wearable sleep-tracking devices either overestimated or underestimated sleep metrics such as total sleep time, total wake time, and sleep efficiency. The study also found that the devices tested weren't accurate in quantifying sleep stages (REM, non-REM).

Garmin Forerunner sleep tracking has been described as "fairly inaccurate" by some users, with reports of the device overestimating sleep time and failing to detect when the user wakes up during the night. It has been noted that the sleep stages on the Garmin Forerunner seem to be based only on movement and do not incorporate advanced data like HRV or HR properly.

In comparison, Fitbit has been found to be more accurate in sleep tracking. Research published in the Nature & Science of Sleep Journal in October 2020 identified the Fitbit Ionic and the Oura Smart Ring as the most accurate devices out of eight commercial brands tested. Fitbit excels in its simplicity and product options, sharing insights into sleep duration, consistency, and different sleep stages. It provides a comprehensive snapshot of the night's sleep and offers a user-friendly interface, making it accessible for those new to sleep tracking.

However, it is important to note that no single device is perfect for sleep tracking. The gold-standard sleep assessment technique, polysomnography (PSG), is currently limited to laboratories or clinics. User error, such as not wearing the device correctly or not enabling certain features, can also impact the accuracy of sleep tracking data.

To improve the accuracy of sleep tracking on Garmin devices, it is recommended to wear the device at least 2 hours before bedtime, keep it on during sleep, ensure the heart rate monitor is active, and adjust the fit for a snug but comfortable feel.

Advanced Sleep Monitoring

In 2019, Garmin announced Advanced Sleep Monitoring, an enhanced capability to more accurately identify sleep stages. This was developed against truth data generated by a clinical device and is the result of a sleep study by Garmin Health, conducted under the supervision of Dr. Suzanne Stevens, Director of the University of Kansas Medical Center (KUMC) Sleep Medicine Clinic.

However, some users have reported issues with the accuracy of the sleep tracking, with some saying that it is fairly inaccurate and useless. One user reported that their watch showed they had spent 1 hour moving around during sleep, which was not true. Another user reported that their watch had detected REM sleep when they were awake. It is important to note that the accuracy of sleep tracking can be affected by factors such as the fit of the device, skin tone, hair, and movement during sleep.

Sleep tracking limitations

Sleep tracking devices are not 100% accurate, and the accuracy of results depends on the device being used. Garmin's sleep tracking feature has been described as "fairly inaccurate", with some users noting that it only tracks sleep based on movement and does not incorporate other data such as heart rate variability (HRV) or heart rate (HR). This can lead to discrepancies in the data, such as the device registering a person as being in deep sleep when they were awake or vice versa.

A study published in the journal Nature and Science of Sleep in 2021 found that most wearable sleep-tracking devices, including those from Garmin, either overestimated or underestimated sleep metrics such as total sleep time, total wake time, and sleep efficiency. The study also found that these devices were not accurate in quantifying sleep stages (REM, non-REM). However, it is important to note that the gold-standard sleep assessment technique, polysomnography (PSG), is not feasible outside of a laboratory or clinical setting, making it challenging to obtain precise sleep data.

Garmin's Advanced Sleep Monitoring, available on many of its smartwatches and fitness trackers, aims to address these limitations by incorporating heart rate and HRV data, along with accelerometer information, to provide more accurate sleep insights. Despite these improvements, some users still report issues with the accuracy of Garmin's sleep tracking, especially when compared to competing products like Fitbit and Oura.

It is worth noting that no device can provide perfect accuracy in sleep tracking, and the best method for determining sleep stages remains in-laboratory PSG. However, the inconvenience and potential impact on sleep quality associated with PSG limit its practicality for regular use. Therefore, while Garmin's sleep tracking technology may have limitations, it can still provide valuable insights into sleep patterns and help users identify potential sleep issues.

Sleep tracking benefits

Sleep tracking has become an increasingly popular feature of modern technology, with an estimated 117 million smart wearables sold in 2019, rising to 233 million in 2022. The benefits of sleep tracking are clear to see, with many people curious about their sleep patterns and duration.

Sleep tracking can provide users with invaluable insights into their sleep hygiene and patterns, which can be useful for those who want to gain some insight into their sleep routine. Sleep tracking can also help users recognise patterns in their sleep habits, such as the ideal time to go to sleep and wake up, the ideal bedroom temperature, and the impact of caffeine, food, and stress on sleep.

Some sleep trackers also provide advice, and while experts have expressed skepticism about the quality of this advice, it can be useful for making adjustments to sleep routines. According to a survey by the American Academy of Sleep Medicine (AASM), 77% of sleep tracker users found the device helpful, and 68% changed their behavior after using it.

However, it is important to note that sleep trackers have limitations and should not be solely relied upon for making decisions about your health. They often measure sleep indirectly through markers like breathing and movement, and while they can offer a sense of what's happening during sleep, they are not always accurate.

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