It had become both the obsession and the nightmare of parents: how to fight against the bad habits adopted by a large part of today’s teenagers in order to prevent them from reducing their quality of sleep to zero? Using screens until bedtime, snacking without setting a schedule, doing physical exercise at all hours: particularly singled out, these three behaviors have just been scrutinized by scientists… who concluded that ultimately, the effects were not so significant.
The research, carried out at the New Zealand University of Otago and relayed by New Atlas, aimed to determine how this type of behavior affected the sleep of pre-teens and teenagers. “Few studies have examined pre-bedtime behavior and how it may impact rest using objective measures such as cameras”notes Chao Gu, lead author of the study and doctoral student in the university’s department of medicine.
The premise is that screen use can disrupt melatonin production and circadian rhythms, exercise can keep the body overly alert, and diet, particularly consuming caffeine or sugary foods, can disrupt sleep.
Most of the evidence supporting these rules comes from questionnaires and cross-sectional studies, which are unreliable and cannot establish cause and effect. The current study aimed to test whether these common pre-bedtime behaviors were actually harmful.
Recommendations too strict?
The study concerns a group of eighty-three young New Zealanders, a small sample which will therefore require subsequent testing on a larger and more diverse population. It shows, for example, that the use of screens in the evening has no significant effect on the total duration of sleep or its quality; on the other hand, the time to fall asleep is 23 minutes longer than that of young people who do not use screens in the period before going to bed.
As for physical activity practiced in the evening, it seems on the contrary that it pushes teenagers to sleep longer – something that school schedules do not always allow. After exercising in the evening, young people slept about 34 minutes more than average. It therefore seems that sport, even practiced shortly before bedtime, produces “good” fatigue and prevents insomnia.
As for the consumption of food and drinks, it may well have no effect on the sleep of the target audience. No significant link has in fact been established between diet and beverage consumption – including products containing caffeine, sugar or fat – and effects on sleep.
These results, which remain to be confirmed, could suggest that current sleep hygiene recommendations are too strict. Would the way in which the body and the brain react to stimuli evolve to match the changes in adolescents’ habits, so that these have as moderate an impact as possible on their sleep and their state of fatigue? This is what the conclusions of the study published in the journal Pediatrics Open Science seem to indicate – pending the results of a new study, currently being carried out among 10-15 year olds.
