What Is A Sleep Tracker And How Does It Work?

August 14, 2017 |

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Wouldn’t it be cool if you could visit a sleep clinic every night and hook yourself up to devices that monitor your sleep quality? While most people don't have access to this kind of technology, you can still track your sleep habits from the comfort of your own home using a sleep tracker.

An estimated 60 million Americans suffer from sleep problems(1), which leaves many people wondering what they are doing wrong at night. A sleep tracker is designed to monitor your sleep habits by keeping track of how much time you spend tossing and turning. They also keep track of how many times you wake up during the night and how much time you spend snoring, which can help determine your quality of sleep.

Here’s everything you need to know about sleep trackers and how they work.

How Does A Sleep Tracker Work?

A sleep tracker is a personalized tool you can use to measure your sleep quality. Most sleep trackers can be worn on your wrist while others fit under your bed sheets. Many of them tend to be included as an extended service to fitness trackers such as the Fitbit. They determine how much time you spend tossing and turning at night, which is a sign that you aren’t sleeping well. You can also download an app on your smartphone that senses your movements at night using built-in motion detectors called accelerometers.

The sleep tracker converts your sleep movements into electrical signals so you can see them in a chart or graph. Some trackers even measure your heart rate changes as the night goes on. This technology is known as actigraphy.

A sleep tracker won’t give you the same results you would get from visiting a professional sleep clinic, but it’s a good place to start if you want to learn more about your sleep patterns. According to Michelle Primeau, an instructor at the Stanford Center for Sleep Sciences and Medicine, sleep trackers are useful because they emphasize good sleep quality. She states that most people in the United States are somewhat sleep deprived (2).

Primeau stated that sleep measuring devices provide an indirect approximation of sleep through movement. She indicated that they make estimations of light sleep and deep sleep based on an algorithm that measures a person’s movements throughout the night.

If you were to visit a sleep clinic or specialist, you would probably be subjected to a polysomnography test, which measures your sleep activity in a controlled environment. It measures your muscle and eye movements, brain activity, heart rate and breathing. It can be used to detect sleep disorders such as circadian rhythm disorders, night time movement disorders, and sleep apnea. While a polysomnography test tends to be the gold standard for measuring sleep, it is often conducted in a sleep lab and doesn’t take into account the rest you would normally get in your own bed.

Are Sleep Trackers Accurate?

A 2015 study published in the International Journal of Behavioral Nutrition and Physical Therapy conducted a review of 22 studies on the validity of sleep trackers. The purpose of the review was to summarize the evidence for the reliability of popular wearable sleep trackers such as Fitbit and Jawbone, which are designed to track physical activity, energy expenditure, sleep, distance covered, and steps.

Results showed that total sleep efficiency and sleep time were over-estimated in subjects who used the trackers. Sleep trackers that used a standard mode setting also under-estimated wake time after falling asleep when compared to data from polysomnography tests. On a positive note, the two sleep trackers showed consistent results when compared against each other (3).

A study published in the Journal of Clinical Sleep Medicine stated that most people are aware that the claims of most sleep tracker devices outweigh the science to support them (4). Authors of the study did not like that sleep trackers rely heavily on the consumer’s movements to determine their sleep quality. They also stated there was a lack of transparency in how they determine a person’s sleep habits. They also did not like that the sleep trackers encouraged bad sleeping habits by telling people to stay in bed longer. The authors of the study concluded that there is no way to determine how accurate sleep trackers are even under ideal circumstances (4).

When presented with this data, the modern sleep tracker designer FitBit claimed that two other studies had proven its effectiveness. A 2016 study conducted on the FitbitChargeHR™ showed good agreement with polysomnography and electrocardiography tests in measuring heart rate and sleep quality (5). Another study concluded that sleep tracker monitoring devices showed high validity for measuring the stages of sleep as well as sleep duration. Results showed that the most favorable sleep trackers were the Fitbit One, Fitbit Zip and Withings Pulse (6).

One of the primary flaws with many sleep trackers is that there is no way for one to determine if you are asleep or if you’re just not moving. Some people naturally toss and turn a lot when they sleep, but this doesn’t always mean their sleep quality is affected. Everyone has different sleep habits that cannot always be determined by a tracker.

An undergraduate student name Jina Yoon at Brown University located in Rhode Island experimented with ten of the most popular sleep tracking devices in 2017. According to Yoon’s research, there are over 500 sleep tracker devices available from approximately 15 different brands (7). Yoon wore ten of the most popular sleep devices for a duration of ten nights and graphed the data.

Yoon wore the following five wristbands on the same arm: Jawbone UP, Fitbit Alba, Microsoft Band, Microsoft Band 2, and AMI MotionLogger. She also placed three phones with the following sleep apps side by side on her bed: Sleep as Android, SleepCoacher iOS, and SleepCoacher Android. Yoon had one phone on her nightstand with the Sleep Cycle iOS app open, and one device with the Hello Sense Sleep Pill clipped to her pillow. Finally, she wore a device that required her to attach two sensors called Hello Sense to her pillow. She utilized these devices for ten nights (7).

Yoon concluded that the Fitbit Alba was the most accurate for measuring sleep versus wake data (7). She mentioned that each sleep tracker was different in design, price and in other factors that you might want to take into consideration when making a personal choice. In the end, she concluded that the devices were very similar regarding how they were structured and used. For example, many of the sleep trackers measured motion or noise and could be worn as a wristband or utilized as an app on your phone.

Yoon stated that the best way to track your sleep is through a polysomnography test. But sleep trackers are more convenient and accessible for casual use. They also cost less and do not require the assistance of a sleep specialist.

fitbit sleep tracker

Tips For Picking Out The Best Sleep Tracker

Although a sleep tracker cannot be used to diagnose a sleep disorder, it can give you an idea of how well you’re sleeping at night. It may even prompt you to seek professional help if you notice something isn’t right on your tracker.

The Fitbit line is one of the most popular lines of wearable activity trackers. It includes a line of several different sleep trackers, including the Fitbit Alba and Flex. Depending on your needs, the Fitbit line ranges from $50 to $130. The Apple Watch Sleep Tracker is another wearable activity tracker that can be worn on your wrist.

When it comes to picking out a sleep tracker, consider the following questions:

  • How much money do I want to spend?
  • Do I want to invest in wearable technology or use my smartphone? Am I willing to attaching sensors to my clothing or pillow?
  • What information do I intend to acquire from monitoring my sleep habits?
  • Do I think I have an underlying sleep disorder?
  • What do I intend to do with the information I discover from a sleep tracker?

If you do not want to spend a lot of money, consider downloading one of these apps to your phone:

  1. Sleep Cycle

The Sleep Cycle app is available for iOS and Android for around $1.99. If you’re a firm believer in not being woken up during deep sleep, this is the app for you. It comes with an alarm clock that only wakes you up when you’re in the lightest sleep cycle so that you won’t feel groggy. It also detects, measures and stores your snoring data. The only downside is that you’ll need to sleep with your phone.

  1. SleepBot

The SleepBot app is free for Android and iOS users. It claims to be the only sleep app that includes sound and motion graphs, a sleep debt log, trend graphs to measure your averages, patterns, and sleep-wake cycle, and other statistics. It also has several customizable alarms and resources to help you fall asleep.

  1. MotionX-24/7

The MotionX-24/7 app is a motion detector that you place under your bed to measure your sleep quality. It records sound clips of when you snore or move in the middle of the night so you can hear what you sound like. You can set the app’s alarm to make sure you aren’t woken during deep sleep. It can also play white noise to help you fall asleep and will fade out once it senses that you’re asleep.

  1. Sleep Time

Sleep Time is an app that uses sensors in your phone to detect your movements during sleep. It features an alarm clock that wakes you up in light sleep cycles, 20 built in alarms, a full history and graph charts, and an easy to read interface. The app costs $1.99 for Android users.

  1. Smart Alarm Clock

The Smart Alarm Clock app is $2.99 for iOS users and claims to be the most advanced alarm clock algorithm to date. It records your sleep sounds and lets you browse through graphs of your sleep duration and what time you were disturbed.

  1. Sleep As Android

Sleep as Android is an app that costs $3.19 for an unlocked version. It allows you to share your sleep data on your social media account. It also backs up to a SleepCloud storage platform, so you’ll never lose your data.

If you want to take your sleep tracker a step further and you don't mind investing some money, here are some top rated sleep trackers:

  1. S+ by ResMed Personal Sleep Solution

The S+ by ResMed Personal Sleep Solution is the first sleep tracker that works without physical contact. It features relatively accurate readings of your sleep stages and when you wake up. It also synchronizes your breathing to play relaxing music or sounds through your phone and measures how adaptable your bedroom is for sleep. Prices range from $45 to $65.

  1. Beddit 3.0 Smart Sleep Monitor

The Beddit 3.0 Smart Sleep Monitor tracks your sleep by using a thin strip that you insert underneath your bed sheet. It hooks up to your smartphone to track your data. It senses when you go to sleep, and a smart alarm wakes you up based on your lightest sleep cycle. Prices range from $130 to $150.

  1. Emfit QS

The Emfit QS measures your sleep by placing a strip under the side of your mattress, not under your bed sheet. It’s a great device for athletes as it measures your heart rate variability, total recovery, and recovery efficiency. This can help you determine what days of the week you should train harder and what days you should rest. It also measures your breathing rate, heart beat, restlessness, and REM sleep. Prices start at $265 on Amazon.com.

  1. Sleepace Reston

The Sleepace Reston works best if you sleep alone. It measures your sleep time, the time you spend awake, and the number of times you toss and turn in more detail than other trackers. Prices begin around $150.

To find the best sleep tracker for you, you may first want to determine what your needs are. If you think you may have an underlying sleep problem, a sleep tracker can help identify where your issues lie. Remember that sleep trackers aren’t designed to diagnose a sleep disorder. Nor do they tell you how to fix your sleep problems. But experts agree that paying attention to your sleep habits is a good way to stay healthy. Since it's not always possible to visit a sleep clinic to measure your brainwaves, a sleep tracker might be the next best thing.