New findings from the Health Behaviour in School-aged Children (HBSC) study in Czechia highlight a concerning trend: adolescents are sleeping less than ever before, with average weekday sleep duration falling below eight hours for the first time. The research, conducted by Palacký University in Olomouc, reveals that only 51% of Czech schoolchildren now meet recommended sleep guidelines, a significant drop from 65% in 2014.

Declining sleep duration and growing social jet lag

The latest data shows Czech children aged 11-15 now sleep an average of 7 hours and 57 minutes on weekdays, a decrease of 23 minutes since 2014. The situation improves on weekends, with adolescents sleeping approximately 9 hours and 31 minutes, but this too has decreased by 12 minutes since 2018.

This significant difference between weekday and weekend sleep patterns points to what researchers call “social jet lag” – a mismatch between biological rhythms and social obligations, particularly school start times. When this gap exceeds two hours, which is the case for 37% of 11-year-olds, 51% of 13-year-olds, and 55% of 15-year-olds, children face increased health risks including depressive states, irritability, obesity, and higher rates of 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,” notes Petr Baďura, data analyst for the Czech part of the HBSC study.

How much sleep do young people need?

According to international health guidelines, children have different sleep requirements based on their age. Children aged 6-12 years should get 9-12 hours of sleep per night, while adolescents aged 13-17 years need 8-10 hours. These recommendations reflect the crucial role of sleep in supporting growth, development, and overall health during these formative years.

The Czech data shows that nearly half of adolescents are failing to meet these recommended guidelines, reflecting a concerning trend that mirrors patterns across Europe but appears to be accelerating in Czechia.

The importance of sleep for health and well-being

Sufficient sleep is far more than just a way to avoid feeling tired. For adolescents, it is a fundamental pillar of healthy development with far-reaching implications for both immediate and long-term wellbeing.

During sleep, the brain consolidates memories and processes emotional experiences, which is critical for learning and psychological resilience. Adequate sleep supports healthy brain development, emotional regulation, and academic success. It also plays a vital role in physical health, supporting immune function, hormonal balance, and metabolic processes.

Insufficient sleep has been linked to a range of negative outcomes including impaired mental health, lower academic performance, and elevated risks of obesity and metabolic disorders. Research also shows connections between sleep deprivation and increased substance misuse, highlighting sleep as a critical protective factor in adolescent development.

By recognizing sleep as a modifiable lifestyle factor – on par with nutrition and physical activity – policymakers, educators, and parents can address a key determinant of youth wellbeing and long-term public health.

Later bedtimes driving the trend

A key factor in declining sleep duration is increasingly delayed bedtimes. The number of 13-year-olds going to bed after midnight has more than doubled since 2014, rising from 6% to 13%. Among 15-year-olds, this figure has increased from 12% to 22% over the same period.

Michal Kalman, head of the HBSC research team in Czechia, suggests that addressing the issue requires a two-pronged approach: “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 left aside.”

Digital devices and sleep quality

The research also reveals a clear relationship between screen time and sleep. Children meeting sleep recommendations spend significantly less time in front of screens compared to their peers who sleep less. Additionally, problematic social media users and gamers are more likely to experience social jet lag, with significant differences between their weekday and weekend sleep patterns.

Recommendations for policy and practice

These findings raise important considerations for policymakers, educators, and health professionals. International case studies suggest that several evidence-based interventions could help address adolescent sleep deprivation: 

• Delaying school start times to better align with adolescents’ biological sleep rhythms

• Implementing national digital hygiene strategies, including device-free hours before bedtime

• Integrating sleep education into school health curricula

• Launching public health campaigns targeting families to promote healthy sleep habits

The Czech HBSC team emphasizes that insufficient sleep should be recognized as a public health concern requiring structural interventions. By placing adolescent sleep firmly on the policy agenda, Czech authorities can address a key determinant of youth well-being and long-term public health.

The HBSC study in Czechia collected data from nearly 15,000 children in 250 schools across the country. This large-scale research was supported by the EU under the Jan Amos Komenský Operational Programme for top-level research.