Sleep Trackers have been around for more than a decade, and these apps or devices are aimed to measure the amount and quality of our sleep. They’ve been successful as today many big brand names, not only in the tech industry but also sports accessory manufacturers (clothes and footwear) develop and market these products. Public interest in fitness has brought these devices to be seen as a complement to pedometers and heart rate monitors.  However, the question is whether their measurements and results are relevant for professional sports coaches and sleep, medicine experts.

To answer this question a number of scientific research projects have been carried out by important universities from around the world. Their objective was to compare data collected by Sleep Trackers with those obtained from two main clinical practices in order to detect sleep disorders; polysomnography and actigraphy. The first conclusion they reached was that due to the type of device used and its way of measuring sleep cycles, the vast majority are based on actigraphy. In its clinical version, this technique records the patient’s movements while they sleep, requiring a specialist who is able to export the data obtained and to interpret them correctly. Sleep Trackers contain an algorithm designed by each brand to carry out this function. And therein lies the main issue in determining their effectiveness. Even though data obtained from professional devices as well as domestic ones can be compared in a laboratory, it is impossible to know whether the algorithm is based on the sleep pattern of the average user. As a commercial secret protected by patents, brands are not prepared to reveal it.

According to what scientists have mentioned in their studies, for the algorithm to be effective the Sleep Tracker must be based on universal validations, in other words, on a large number of people. It would be necessary to use males and females with different occupations, age ranges and social and cultural origins. This is because the best sleep is not monolithic and universal: it depends on the factors that surround each person, and on a wide range of conditions. In fact, the ideal sleep for an athlete who is training differs from that of a person who has a sedentary job.

However, as far as we know, Sleep Tracker algorithms make no such distinction. This is why they are not useful to identify sleep disorders, something which is only possible in a specialised clinic.

That said, the fact that these devices are not useful to professional sleep physicians, does not mean that they are useless to coaches, especially if they are training youth teams. To know how they have slept using a Sleep Tracker may reinforce the behaviour of an adolescent or young athlete, as relevant sleep data is shown and adds to the natural interest in technology youth have at this age. The same research to which we alluded previously reveals that the effectiveness of these measurements’ sways between 78.8% and 99.1%, according to the brand and type of sensors used. There are wristbands, which assure us they are able to distinguish between the REM and NREM phases during sleep. Others can be placed in a bedroom to monitor activity, although they are only effective if the person is sleeping alone, as a partner would interfere with the monitoring. Microphones, in combination with the ones mentioned above, record breathing and snoring. Some, which stick to the body, measure heart and respiratory activity. They all share the capability of storing the data, which at the end of the night indicates how well the user has slept and which aspects of rest must be reinforced.

This is far from being a negligible aspect in youth sport, given the epidemic of irregular sleep that affects all adolescents around the world. FC Barcelona is especially interested in this issue and in order to help provide a solution it has developed the Sleep Guide in collaboration with the Ad Salutem Institute and Allianz. Aimed at those who train at La Masia, its recommendations also explain why good sleep contributes to maximise performance, reinforce school learning and in the long run prevent injuries. As important as all of the above is promoting interest in tracking personal rest, until it becomes as natural as nowadays with nutrition. When youngsters ask whether or not to use a Sleep Tracker, it will be essential for them to know that they should not be used to detect real disorders, such as insomnia, narcolepsy or hypersomnia, among others. In the same way that the work of a coach cannot be replaced, neither can medical diagnoses be carried out by applications and sensors, however advanced they may be. The coach can improve his knowledge on the psychology of these athletes using these devices, which can indeed reinforce positive aspects and may, as with other technologies, be advantageous.

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