The science behind sleep tracking: How accurate are fitness gadgets?

What's the Best explains the science behind sleep tracking.

Sleep tracking

by Jack Barrell |
Updated on

You might not have given much thought to the exact science of your sleep, but there’s a lot to be said about how our sleep impacts our lives and the modern measures we can take to improve our sleep. This conversation around sleep has become far more relevant thanks to new and developing technologies focusing on sleep tracking. Sleep trackers use similar technology found in some of the best fitness trackers, monitoring noise, movement, and some of your basic vitals. We’ve witnessed the emergence of countless sleep-monitoring gadgets, apps, and smart tech, but it’s extremely important to understand what they mean and how they work.

We’re taking a closer look at sleep tracking, investigating the science and the methods' reliability. Sleep tracking technology can be an intuitive tool, but knowing how to use it, interpret it, and learn from it shouldn’t be dismissed. Here’s everything you need to know about sleep monitoring from us and some additional experts.

Understanding sleep tracking

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Let’s start from the beginning: What is sleep tracking? Sleep tracking is the observation of your sleep through sleep monitoring gadgets such as sleep trackers, smartwatches, fitness trackers, and even some mobile apps. These devices are designed to pick up on specific bodily functions while you sleep.

By monitoring your breathing, heart rate, body temperature, sound, and movement, this technology can produce incredibly accurate data regarding your sleep. You can then begin to paint a picture and better understand what happens after your head hits the pillow.

Sleep tracking can also encourage positive change. If you can discover the weaknesses in your sleep pattern or sleep routine, you can get to the bottom of it and make lifestyle changes to strengthen these flaws.

The science of sleep monitoring

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There are differences between smartwatches and fitness trackers across the board, and a wearable smart gadget needs to be equipped with specific tech to monitor sleep effectively. Sleep monitoring gadgets can pick up on, track, and highlight the nuances of your sleep cycle through high-tech sensors, detectors, and accelerometers. They achieve this in a few ways, and it’s important to understand each one.

Movement and breathing are two indicators to determining the quality of your sleep. Specifically, breathing and movement can indicate your overall wakefulness and sleep depth. Wearable sleep-tracking gadgets like smartwatches are equipped with accelerometers which can track movement and heart rate variability to monitor the different stages of sleep. While app-based trackers cannot pick up precise movement or breathing, they can still detect noises like snoring during the night.

Sleep monitoring technology assesses the three sleep stages, including REM (Rapid Eye Movement), deep sleep, and light sleep. Here’s what they all mean:

REM (Rapid Eye Movement) - Sleep occurs mainly in later stages of the night and is characterised by dreaming and increased brain activity and plays a crucial role in processing memories and emotions.

Deep sleep - Occurs mostly at the beginning of the night and is important for physical recovery and health as it’s when your body is in its most restorative state.

Light sleep - Serves as a transition phase between deep sleep and REM sleep and facilitates mental and physical relaxation.

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Accuracy of sleep tracking devices

Carolina Goncalves, Superintendent Pharmacist at Pharmica, gave us some insight into the overall accuracy of sleep tracking. She proposes that “sleep tracking as a concept is theoretically sound. Numerous studies suggest that modern sleep-tracking devices can provide useful measurements on several sleep parameters such as sleep efficiency, time, and the entering and exit of various sleep stages.” So, sleep-tracking gadgets can be very accurate, given that they do not exceed their capabilities.

Polysomnography is the medical practice of diagnosing sleep disorders through analysing brain waves, eye movements, and muscle activity. It’s extremely important to note that this is a completely different kettle of fish to sleep tracking. The data provided from sleep monitoring devices is not to be taken as medical advice, and any concerns over your sleep should be relayed to a medical practitioner.

Factors affecting accuracy

Unfortunately, it’s not as simple as picking up any old health tracker gadget, firing it up, and expecting a flurry of comprehensive data. Sleep expert Hafiz Shariff stresses that “no device is 100 per cent accurate – even the best tend to provide a general overview of your sleep patterns. However, calibrating these devices and using them consistently can enhance their accuracy.” Calibration is a key step to making sleep monitoring accurate and reliable. Not all sleep trackers are made equally, and no user is the same.

Sleep monitoring is dependent on the user and there are steps you can take to gain the most accurate results. Your proactivity and cooperation are important factors to ensuring the highest accuracy. Planning a regular sleep schedule is the first thing you should be doing if you want to begin sleep monitoring effectively. Establish fixed times every day for when you go to sleep, and when you wake up. Not only is this already a great way to improve your sleep pattern, but it’ll increase the chances of getting reliable and accurate sleep data.

Interpreting sleep data

Let’s say you’ve got everything in place, have a stable sleep pattern, and picked up a reputable sleep tracker. Now, you want to know how to interpret the data correctly. Sleep trackers will point towards periods of restlessness and discomfort during your night’s sleep. If this is the data you’ve received, you can begin experimenting and making environmental changes. You can alter room temperature, swap out for a new set of pillows, or change your light intensity and colour exposure. Sleep monitoring, especially at the beginning, will be a trial-and-error process. There’s no getting around that fact.

Benefits and limitations of sleep tracking and fitness gadgets

Fitnes tracker
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Sleep tracking can be massively beneficial for almost any lifestyle. Although, when technology and our health become interwoven, there are always two sides to the argument.

Let’s start with the principle of sleep tracking and monitoring. On paper, sleep tracking can be a force for positive change. Jules Goldberg, sleep monitoring app developer behind SnoreLab, SnoreGym, and Sleepwave shares his attitude towards sleep monitoring and the ethics he’s infused into his apps. “By shedding lighting on that part of our lives that we cannot see, sleep data is enlightening and can encourage you to make positive lifestyle changes.” So, we can establish that the benefits don’t come from sleep monitoring alone, but by being proactive when interpreting the data it records. One of the greatest benefits sleep tracking can provide anyone is knowledge and education.

Like most technology, especially the kind that works in conjunction with your health and lifestyle, there are always limitations and sometimes risks. Sleep monitoring tech is no exception, whether it be full on devices or just apps, there are aspects everyone should be mindful of.

For starters, not all sleep trackers or sleep-tracking apps are made equally. There are always going be differences between one sleep tracker to the next, and no, we’re not just talking about design. Across different manufacturers, you’ll find totally different software and firmware in sleep-tracking gadgets. This becomes a limitation for the wider practice of sleep tracking because it can be difficult to tell what is accurate. You can use a certain sleep tracker or sleep monitoring app, but there’s a good chance that your findings might somewhat vary to another brand or developer.

Accuracy is paramount when it comes to sleep tracking and monitoring, you can’t afford to work off of inconclusive or inconsistent data.

It's also been argued that the process of sleep monitoring can have negative psychological effects on some users. Put it like this, let's say you've just started sleep monitoring and your device comes back with some negative results about your sleep. This could work counteractively, these negative results might stress you out even further, leading to your quality of sleep plummeting. This scenario is even more dangerous if the results you get back aren't even accurate to begin with.

Getting the most out of a tracker gadget

If you’re ever going to make the most of your sleep tracker, you have to start at the very beginning. When you choose any tracker device, you want to get your money’s worth, and you want the features that align with your goals.

Fitness trackers are going to be more focused on sports, exercise, and physical performance, packed with a range of health and fitness features. While some may feature basic sleep tracking features, it’s not their primary function. If your only priority is the monitoring of sleep, a dedicated fitness tracker might not be the way to go.

A similar approach should be taken towards smartwatches too. The market for smartwatches is incredibly diverse because a smartwatch is a multi-functional gadget. Most examples offer a balance of features catering to fitness, sleep tracking, and simple day-to-day tasks. We’d recommend thoroughly researching a smartwatch before purchasing, especially if you’re looking for one that offers cutting-edge sleep-tracking features.

Closing thoughts

Sleep monitoring can be a phenomenal tool, if used in the right context, capacity, and with the correct approach. Is it a 100 per cent flawless method of obtaining your sleep data? No, but it’s the closest you can get without professional medical intervention. Sleep tracking technology has progressed to a point where it is widely seen as reliable, given the right environment and that it’s used optimally.

If you’re interested in learning more about your sleep, improving your sleeping habits quality of sleep, then sleep trackers are the route to go.

Jack Barrell is a Tech and Fitness Writer and Reviewer for What’s the Best. He is invested in the entertainment space and also keeps well in the loop with the latest sports and exercise trends too. On his off days, Jack can usually be found either in the gym – or watching his favourite Star Wars for the thousandth time.

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