Warning by HBSC study researchers: Czech children are sleeping increasingly less

According to the findings of the HBSC study, whose researchers are based at the UP Sts Cyril and Methodius Faculty of Theology (UP CMFT), Czech children and teenagers are sleeping less each year. For the first time in history, the average weekday sleep duration has fallen below eight hours. Only one half of Czech schoolchildren get the recommended amount of sleep. They are thus suffering from a sleep deficit so great that it cannot be compensated at the weekend. The discrepancy between the weekday and weekend sleep patterns of some schoolchildren has become a phenomenon called social jet lag.

Czech children and teenagers are experiencing a gradual reduction in sleep duration. On weekdays, they spend an average of 7 hours and 57 minutes sleeping. Since the last data collection in 2018, the sleep duration of children aged 11–15 has decreased by 11 minutes. Compared to national data from 2014, the difference is already more than 20 minutes. This means one in two school children (49%) are sleeping less than the recommended minimum, whereas in 2014, only 35% of schoolchildren fell into this category.

“Sleep is vital for children’s healthy development, as well as school performance and overall life satisfaction. In contrast, poor quality or insufficient sleep is directly linked to a wide range of problems, including an increased risk of mental health problems. Research shows that children in the Czech Republic perceive the world as a dangerous place and, unfortunately, there is a growing level of anxiety and depression, and an increasing number of suicide attempts by children. Therefore, instead of constantly ‘putting out fires’, we need to focus on coordinated prevention, educate children and parents about sleep hygiene, and make sure that mental health services are accessible to all those in need. Our top priority remains that all children are provided with the conditions for a happy and healthy childhood,” said Klára Šimáčková Laurenčíková, the Czech Government Commissioner for Human Rights.

They sleep better at the weekend – but then there’s social jet lag

The situation is better on weekends, holidays, and public holidays. Children sleep an average of 9 hours and 31 minutes, that is an hour and a half longer than on school days, and roughly two-thirds of them (65% of boys and 67% of girls) meet sleep recommendations. However, even weekend sleep is gradually getting shorter. Compared to 2018 research data, children sleep 12 minutes less on their days of leisure.

Moreover, “catching up on sleep” at the weekends indicates social jet lag, i.e. the mismatch between biological rhythms and social obligations – i.e., the beginning of the school day in the case of schoolchildren. If the difference between weekend and weekday sleep exceeds 2 hours, which is the case for 37% of fifth-graders, 51% of seventh-graders, and 55% of ninth-graders, children are at risk of increased health risks. These include depressive states, feelings of irritability and nervousness, and being overweight or obese. Researchers also point to a link between social jet lag and increased substance use.

“Late bedtime is an important indicator. For children who go to bed very late, our statistics show a 3–6 times higher risk of regular smoking or repeated drunkenness. Increased health risks are faced both by those who experience a significant deficit accumulated during the week, as well as by those who cut their sleep even shorter on weekends compared to school days,” points out Petr Baďura, data analyst for the Czech part of the global HBSC study from the Olomouc University Social Health Institute (OUSHI) at UP CMFT.

Trend: Children going to bed later

Czech children are going to bed increasingly later. In the case of seventh and ninth graders, the number of those who go to bed after midnight has doubled since 2014 (from 6% to 13% in 13-year-olds and from 12% to 22% in 15-year-olds). The decreasing overall sleep duration is due to the postponement of the moment when children fall asleep. The time when school starts, which means the time of getting up in the morning on weekdays, has not changed much in Czech schools over the years. This raises the question of whether starting school later would help to increase sleep duration or reduce the incidence of social jet lag.

“Although it is not directly the subject of our research, this question cannot be avoided when looking at the data. We think the answer to it is ‘Yes’. For one thing, children’s sleep duration is shortened by falling asleep later. On the other hand, it is limited by getting up early for school. Change makes sense at both ends. We need to work with children, but also with us adults, to improve habits related to falling asleep. But changing the wake-up time, i.e. starting school later, is a perfectly valid consideration and should not be ignored,” says Michal Kalman, head of the HBSC research team.

Sleep in the light of the screen

What is the relationship between sleep and screen time? The latest data shows that schoolchildren who meet sleep recommendations spend less time in front of a screen on average than their peers who spend less time sleeping. Or vice versa – schoolchildren who are in control of their screen time are more likely to meet sleep recommendations. At the same time, 11–15-year-olds who sleep more on weekends, or less than on school days (increased risk of social jet lag), more likely become “problematic” social media users and gamers.

“Reduced sleep duration in adolescents is a growing public health problem with serious consequences for mental and physical wellbeing. Almost half of Czech schoolchildren sleep less than recommended, thus increasing the risk of depression, anxiety, obesity, and substance abuse. Evidence shows that starting the school day later, improving sleep habits, and reducing screen time can have a positive impact. WHO encourages legislators, educators, and families to take action to promote healthy sleep habits in children and ensure a better future for them,” said Zsofia Pusztai, Head of the WHO Office in the Czech Republic.

Further details and materials on the topic can be found on the Healthy Generation website.