Author: Júlio Costa

Ph.D. Student in Sports Science. Researcher at Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D) and at Portugal Football School (FPF).

Abstract

Sleep is considered vital for human health and well-being, being fundamental to physiology and cognitive functioning. Considering that the number of international competitions, of professional and recreational sports leagues for football athletes, of different age groups and sex, has increased significantly, this has provided new opportunities to train and compete. Consequently, athletes withstand high demands (eg. loads) of training and/or competition, being often exposed to various factors and environments that can cause sleep disturbances. This issue becomes even more relevant, given that in some countries, athletes (professional and non-professional) usually start training very late, close to bedtime, due to their daily commitments (eg. school/university) that they have to conciliate with the training and game schedules. Thus, it is necessary to investigate methods that are sensitive and non-invasive to monitor sleep patterns in athletes, in order to promote better sleep hygiene and, consequently, a better sleep and a better recovery.


Body of the article

One of the fundamental aspects for the recovery, well-being and performance of an athlete, is to obtain a sufficient amount and quality of sleep, especially during the competitive period. In fact, athletes and coaches of various sports have selected sleep as the athlete’s most important recovery strategy. A minimum of 7-9 hours of total sleep time and sleep efficiency (ie percentage of total sleep time) ≥85% per night is generally recommended to promote a better health and cognitive function in adults aged between 18 and 60 years old. Although, there is still no consensus regarding the amount of sleep that an athlete should get to maintain an optimal performance, athletes who sleep less than 7 hours per night may be more likely to get an injury.

Previous studies have analyzed the relationship between exercise and sleep, suggesting that some factors may affect sleep and recovery such as the athlete’s chronotype (circadian rhythm of a person), or the load and/or hour of the day that the athlete practices exercise. In some of our studies, although female football players from the first division Portugal have accumulated adequate sleep (≥7h), it was possible to observe a decrease in sleep duration after training sessions held at night (9:00 pm). In fact, a consistent reduction in total sleep time and a delay in sleep latency (in other words, time they took to fall asleep) was observed after training sessions held at night compared to rest days. These results are in line with other studies, where it was observed that players on game days completed before 6 pm, had adequate sleep, unlike game days and training sessions held after 6 pm, in which the total sleep time was significantly reduced.

Vitale et al (2018) observed that the quantity and quality of sleep were lower during the night immediately after the game played at night, in comparison with the previous or subsequent nights, in both female and male athletes. For example, in our study with the female Portuguese National Team, during the nine days of the international tournament (Algarve Cup 2018), there was a significant reduction in total sleep time and sleep efficiency after the game played at night (7:00 pm) compared to the other games played during the day (3:00 pm). In this way, our results suggest that the exercise performed close to bedtime, might cause difficulties in the moment to fall asleep. An explanation for the observed results may be the length of bedtime caused by the schedule/schedule of training sessions and/or games.

Thus, it is important to apply strategies to promote adequate sleep and recovery, especially after competitions that are held at night and to educate athletes about the subject. In order to detect and control sleep disorders, it is important to monitor sleep habits and perceptions about sleep, through subjective and/or objective measures. However, the sleep needs in athletes remain unknown, given that monitoring in this type of population is not very usual. The recommended equipment for monitoring sleep is the polysomnography, which uses superficial electrodes to monitor physiological parameters such as brain, muscle, cardiac and respiratory activity. Polysomnography is particularly useful to investigate sleep pathologies, including sleep-breathing disorders and sleep disorders caused by concussions. Actigraphy, on the other hand, uses accelerometers placed on portable devices to record movements that, analyzed using algorithms, estimate the quality and quantity of sleep. Actigraphy is less expensive, non-invasive and can be used in training/game routines (usually two weeks of monitoring). Thus, actigraphy is the most accessible method for objectively monitoring athletes’ sleep at night. “Sleep diaries” are also used to record the date/time of the beginning and the end for all sleep periods (in other words, night sleep and daily naps). In summary, although there are several consequences associated with sleep disturbances in athletes, identifying sleep problems (eg. monitoring through actigraphy), and following the recommendations for good sleep hygiene, can allow the athlete’s performance to reach the highest level in a safer and healthier way. Furthermore, according to our results from the observational analysis of sleep patterns and the training and game load, it can help coaches and clinical professionals to identify sleep disturbances after training and games in football players, which can constitute relevant information when prescribing individual training load and time management in football.


Practical Implications

There is a need to use sensitive and non-invasive methods (such as accelerometers) to monitor sleep patterns in order to promote better sleep hygiene and consequently an efficient recovery, especially when sessions or games are held close to bedtime. One of the important aspects of our studies and novelty in sleep research in football athletes, is the use of accelerometers during sleep in a “real scenario”. Each athlete performed wrist accelerometry recordings in their homes/hotel, so that sleep habits were not limited by the study procedures and thus confer greater ecological validity to the investigation. It is therefore suggested that athletes and coaches organize not only the schedule of training and competition, but also take into consideration sleep routines to facilitate a more efficient recovery/performance.

Finally, athletes should use good sleep hygiene to maximize sleep. Some of the strategies for good sleep hygiene in athletes are : the room must be between 18-20ºC, dark and quiet; avoid watching television, using tablets and mobile phones, at least 1h before going to sleep; maintain a regular schedule for sleeping and waking up (in other words, create a sleep routine, always trying to lie down and wake up at the same time of the day); appropriate naps (~30 min and not in the late afternoon); be aware of the food and fluid intake before going to sleep (in other words, not going to bed after consuming lots of fluids, as it can cause sleep to be interrupted for trips to the bathroom) and avoid sleeping too late on the days “off” (that is to say, on days without training and/or competition).


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