Fitness Watches: Reliable Sleep Trackers Or Gimmicky Gadgets?

Sleep-tracking devices have become increasingly popular, but how accurate are they? Sleep trackers can be useful for people who generally sleep well and want to track or improve their sleep routine. However, for those who have poor sleep or mental health conditions, sleep trackers may do more harm than good. While they can provide insights into sleep efficiency, restfulness, readiness, and latency, it's important to remember that they may not always accurately measure sleep. The accuracy of sleep trackers varies, and factors such as comfort, user experience, and ease of use also play a role in their effectiveness.

Accuracy of sleep trackers

The accuracy of sleep trackers varies depending on the device and the individual. No commercially available sleep tracker can perfectly analyse your sleep or diagnose a sleep disorder. However, some trackers can identify trends in your sleep, monitor your activity and heart rate, and provide advice on improving your rest and fitness.

A study compared 11 sleep trackers against polysomnography tests (PSG) and found that the Pixel Watch, Galaxy Watch 5, and Amazon Halo Rise performed well at measuring sleep stages, while the Oura Ring and Apple Watch were better at measuring sleep efficiency and sleep latency. The Fitbit Sense 2, Google Pixel Watch, and Galaxy Watch 5 also showed superior performance in the deep sleep stage.

It's important to note that sleep trackers that rely solely on movement may be inaccurate for people with insomnia, as they tend to remain very still while trying to fall asleep. Watches that incorporate heart rate data tend to be slightly more accurate when measuring sleep duration because heart rate fluctuates during different sleep stages. However, even devices that track heart rate may not be entirely accurate due to limited research and variations between devices.

Battery life and charging are also important considerations when choosing a sleep tracker. Some sleep trackers require daily or nightly charging, which may be inconvenient for some users. The Withings Scan Watch 2, for example, offers a long battery life of up to 30 days between charges. Additionally, wearable sleep trackers are generally considered more accurate than trackers that are placed over or under the bed, as they can provide more personalised data.

In terms of comfort, some users have found certain watches, like the Apple Watch Series 8 and the Garmin Watch Venu Sq 2, uncomfortable to wear to bed. On the other hand, the Oura Ring has been praised for its comfortable, lightweight fit, making it ideal for sleeping. It also provides a wealth of sleep data through its app, including insights into sleep efficiency, restfulness, readiness, and latency.

Sleep trackers and mental health

Sleep trackers are wearable devices that track various metrics to help improve sleep. They typically use accelerometers to track motion and heart rate sensors to monitor heart rate variability, respiratory rate, and skin temperature. While sleep trackers can increase awareness of sleep habits and encourage healthy sleep behaviour, they are not for everyone.

Sleep is vital for maintaining good physical and mental health. However, the overuse of wearable devices has been shown to increase health anxiety and depression. Similarly, sleep tracking can sometimes increase anxiety about insomnia and do more harm than good. People with insomnia tend to remain very still in bed in an attempt to fall asleep, but as sleep trackers only measure movement, watches are unable to differentiate sleep from wakefulness in these cases. This can lead to further anxiety about sleep loss, resulting in more sleeplessness.

Additionally, the "sleep score" given by sleep trackers can affect the user's emotional state and concentration levels. In a study, participants who were told they had a poor night's sleep showed lower mood, difficulties with daytime thinking processes, and increased sleepiness. On the other hand, those who were told they had a great night's sleep showed higher mood and better concentration. This is a concern, especially for those with poor sleep or mental health conditions, as it may worsen existing mental health issues.

While sleep trackers can provide insights and help develop better sleep habits, they should be used with caution. If you have concerns about your sleep quality, it is recommended to consult a health practitioner.

Wearables vs. non-wearables

Wearable sleep trackers are devices that can be worn on the body, such as rings, watches, headbands, or eye masks. They are designed to monitor your sleep patterns and provide insights into your sleep quality. These trackers can identify trends in your sleep, monitor your activity and heart rate, and offer guidance on improving your sleep and fitness. While they offer a convenient way to track sleep, their accuracy may vary, and they may not be suitable for those with insomnia or mental health concerns.

Non-wearable sleep trackers, on the other hand, are devices that do not need to be worn on the body. Examples include sensors placed under your mattress or smart mattresses with built-in sensors. These trackers collect data while you sleep without the need for direct contact with your body. They can be more affordable and less bothersome to use than wearables. Non-wearables can often be plugged in, eliminating the need for frequent charging, which is a common requirement for wearable devices.

When comparing wearables vs. non-wearables, it's important to consider your personal preferences and needs. Wearable devices offer the convenience of having the tracker on your body at all times, providing continuous data collection. They are ideal for those who want insights into their sleep patterns and are curious about how different factors affect their sleep. However, wearables may be uncomfortable for some people to wear to bed, and their accuracy can vary depending on the technology used.

Non-wearable devices, such as under-mattress sensors or smart mattresses, provide a more passive form of sleep tracking. They are suitable for those who find wearables uncomfortable or bothersome. Non-wearables can collect comprehensive data without the need for direct body contact, and they often have longer battery lives or can be plugged in. However, they may not offer the same level of portability and discreteness as wearables.

The choice between wearables and non-wearables ultimately depends on your individual needs and preferences. If you prioritize comfort and want a more passive tracking experience, non-wearables might be a better option. On the other hand, if you value portability and the ability to track your sleep throughout the day, wearables may be more suitable. It's worth noting that while these devices can provide valuable insights, they should not replace professional medical advice or diagnosis.

In terms of specific recommendations, the Oura Ring Gen3 and the Whoop 4.0 have been praised for their accuracy, user experience, and comfort among wearable sleep trackers. The Oura Ring offers accurate heart rate data and easy-to-follow guidance, although its activity tracking could be improved. For non-wearables, the Withings Sleep Mat has been highlighted as a good option, as it tracks movements, breathing, and heart rate, and provides insights through the Withings Health Mate app.

Sleep trackers and heart rate

Oura Ring

The Oura Ring Gen 3 and Oura Ring 4 are popular choices for sleep tracking. The ring offers consistently accurate heart-rate data, in-depth data on sleep stages and sleep quality, and comfortable, lightweight wear. It also tracks blood oxygen, heart rate variability, respiratory rate, skin temperature, and more. However, its activity tracking needs improvement, and it requires more effort to check your stats mid-workout due to the lack of a screen.

Whoop 4.0

The Whoop 4.0 provides a wealth of data, including sleep tracking and post-workout insights. It excels at logging both sleep and exercise, but its interface can be intimidating for some users.

Fitbit Inspire 3

The Fitbit Inspire 3 is an affordable and feature-packed option for sleep and heart rate tracking. It offers basic activity and sleep features, including tracking steps, heart rate, calories burned, sleep, and overnight SpO2. It has a bright screen and a simple interface, making it easy to monitor your health metrics.

Apple Watch Series 10

The Apple Watch Series 10 offers accurate workout pulse readings and advanced running metrics. It also includes a sleep apnea detection feature, tracking your sleep, body temperature deviations, fertility windows, and more. However, the battery life is relatively short, requiring frequent charging.

Google Pixel Watch 2

The Google Pixel Watch 2 is a lightweight and comfortable option for sleep tracking, with improved heart rate sensors and sleep and stress tracking features. It offers accurate heart rate and GPS tracking, although the battery life is shorter than some other smartwatches.

While these devices can provide valuable insights into your sleep and heart rate, it is important to remember that they are not medical devices. If you have concerns about your heart rate or sleep, it is always best to consult a medical professional.

Top-rated sleep trackers

While no commercially available sleep tracker can perfectly analyse your sleep or diagnose a sleep disorder, some are better than others. Here are some top-rated sleep trackers:

Oura Ring Gen 3

The Oura Ring Gen 3 is a stylish, comfortable, and accurate ring tracker that offers consistent heart-rate data and easy-to-follow guidance. However, its activity tracking needs improvement. It is also worth noting that the shape and weight of the ring can take some time to get used to, and the tracker requires recharging roughly every other day.

Whoop 4.0

The Whoop 4.0 is a wristband tracker that excels at logging sleep and exercise, providing tons of data. However, its interface can be intimidating. It is comfortable to wear and can also be attached to other garments, like a sports bra or compression top. It helps optimise sleep by monitoring your heart rate, respiratory rate, blood oxygen levels, and skin temperature. It also features a smart alarm designed to prevent grogginess.

Fitbit Inspire 3

The Fitbit Inspire 3 is a great choice if you want to track your workouts and are curious about your sleep. It is worth noting that you will need a Fitbit Premium subscription to see deeper sleep insights and your Daily Readiness score.

Withings ScanWatch 2

The Withings ScanWatch 2 is a high-quality sleep tracker for those who want a thinner, more traditional watch look. It has a smooth and streamlined design, making it comfortable to wear during the day and at night. Its app is user-friendly, simple, and appealing.

Muse S Headband Sleep Tracker

The Muse S Headband Sleep Tracker has sensors that measure brain activity to gauge the amount of time spent in different sleep stages. It also tracks movement, heart rate, and breathing. It is designed to be used with the Muse app to enhance meditation and breathwork. However, some sleepers may find it uncomfortable to wear a headband during the night, and an annual subscription is required to access the meditation features.

Frequently asked questions