Sleep Aids: The Best Tools for Better Sleep Quality

If you believe the advertising claims, smartphones, smartwatches, and fitness trackers can now measure not only recovery and stress levels but also sleep—backed up by numbers, colorful graphics, and plenty of tips on how to improve your sleep quality.

In this article, with the help of our BLACKROLL® recovery expert Dr. Lutz Graumann, we explain which technologies are best for measuring sleep and which parameters play a role in tracking it.

A sleep tracker records your sleep, can measure sleep quality, and provides you with information about your sleep patterns throughout the night. This data allows you to draw conclusions about sleep depth, sleep duration, and sleep quality—as well as whether you might have a sleep disorder.

However, before you start using one, Dr. Lutz Graumann recommends keeping a sleep or performance diary first.

The second group of gadgets designed to monitor sleep and measure your sleep quality includes so-called wearables.

The most popular wearables are the well-known fitness trackers and, of course, smartwatches. During the day, these devices track how much we move and use that data to estimate—often inaccurately—how many calories we’ve burned. At night, they can use built-in motion sensors to determine whether we’re asleep or awake. But that’s not all. The range of functions offered by these wearables varies, as does their price. There are models that not only measure and record heart rate but also heart rate variability. When interpreted correctly, this value can serve as an indicator of recovery and even provide clues about impending infections.

Based on these and other parameters, the information content and precision of sleep quality measurements can be optimized—provided they are interpreted correctly. And that’s determined by the “artificial intelligence” of the underlying algorithm. All collected and measured data is synchronized, processed, and then visualized in the accompanying app. This allows wearables users to see just how active they really were and how long they slept in each sleep stage. The accuracy of wearables and smartwatches that track activity and recovery using accelerometry and photoplethysmography —that is, movement and heart rate—is constantly improving. While measurement errors still occur during the day during intense physical activity, making meaningful analysis impossible, at rest, however

How does photoplethysmography work?

Measurement via photoplethysmography (PPG) works using infrared radiation. A specific area of skin, such as the wrist, is illuminated with a wavelength of 800 to 1000 nm (nanometers). The absorption or reflection of the infrared light detects fluctuations in blood flow intensity, calculates the interval between heartbeats, and thereby derives the pulse and heart rate variability. Hemoglobin in the blood absorbs infrared rays more strongly than the surrounding tissue. When blood flow decreases, however, the reflection of the infrared light increases.

While wearables such as the Apple Watch or sleep trackers from Garmin or Whoop determine the collected data using photoplethysmography (PPG), the Nambaya device employs a different measurement method: the ECG (electrocardiogram). The ECG stands out significantly from PPG, particularly in terms of accuracy. This is mainly because the blood in our vessels does not flow in a constant stream but rather bubbles along more or less randomly. Calculating heart rate variability via PPG therefore yields more of an average value, whereas the data quality from an ECG monitor is consequently many times higher and more detailed. However, the type of measurement you choose always depends on the goal you want to achieve.

Most wearable manufacturers, such as Fitbit or Withings, now offer the calculation of a sleep index (known as a “sleep score”) as their latest feature.

This is a simple numerical value that is calculated based on various complex factors related to sleep and reflects its quality. Ultimately, a numerical value is determined for the sleep score, indicating how much and how well you slept. Common parameters used for evaluation include sleep duration (total time slept), sleep depth, sleep interruptions, the regularity of going to bed and waking up, the time it takes to fall asleep (sleep latency), and the time it takes the sleeper to wake up.

Depending on the provider, the sleep index is calculated and displayed—usually as a number on a scale from 1 to 100—that categorizes sleep as poor, acceptable, good, or excellent. In addition, users receive an analysis providing insights into the factors that influenced their sleep, allowing them to draw conclusions about how to improve it.

If you may be suffering from sleep disorders, using a sleep app or a wearable device can provide you and your doctor with initial insights into your sleep patterns. With the help of these smart tools, you can track your sleep without having to manually fill out spreadsheets yourself. Sleep logs or sleep diaries typically consist of pre-designed tables where you record, for at least 14 days, when you went to bed and woke up, how long you felt it took to fall asleep, how much sleep you estimate you got, and how you would rate your periods of wakefulness during sleep. The advantage of a sleep diary over wearables is that it encourages you to actively engage with your sleep. By filling it out regularly, you’ll become your very own sleep expert.

The advantage of modern technology lies in its simplicity—it automatically provides you with an analysis.

Whether you use a sleep diary or a wearable, if you track your sleep regularly, a conversation with a doctor can help determine whether you have sleep disorders that require treatment or if you might simply need to make some changes to your sleep environment to improve your sleep.

What to Look for When Buying

If you’re thinking of buying a wearable, you should first find out what technology and sensors are built in. However, it’s not just the measurement methods used that matter—the specific selection of algorithms for the analyses, and thus the reliability of the sleep and recovery assessments, is also crucial. This requires that the user always be able—despite automatic data collection—to manually adjust certain values, such as start and stop times.

In practice, it ultimately becomes clear that users will adopt wearables on a long-term basis if they are comfortable to wear, easy to use, and employ a measurement method that is minimally invasive.

Whether you choose an app on your smartphone or one of the many gadgets on the market to optimize your sleep depends entirely on your preferences and needs. To make a decision, you should first consider the purposes for which you want to use sleep trackers and sleep aids, and what can best be integrated into your daily routine. For a final assessment, it’s worth taking a comparative look at manufacturers’ websites and online forums.

When using tracking tools, alsokeep in mind that too much pressure can negatively affect your sleep. Focusing too intensely on tracking—especially if you already have sleep disorders—can put us under even greater pressure to succeed.

The result: technology is used to virtually force better, deeper, more restful, and longer sleep.

And pressure—like any form of psychological stress—is toxic to relaxation and, therefore, to sleep as well.