We live in an increasingly technologically connected society, which even extends to children – for example, 74% of children (9-16 years old) in the UK use a mobile phone, with most receiving their first phone at the age of 10 years old; while around half have a television in their bedroom at age 7. For many it can be difficult to switch off at the end of the day – the allure of one more video, or another scan of social media can be strong. As such, many children use technology at bedtime, which may impact on their sleep as the light emitted by these devices has a higher concentration of ‘blue light’, which affects the levels of melatonin, a sleep-inducing hormone. Previous research has shown the importance of sleep on children’s health and behaviour, and so Fuller and colleagues conducted a study looking at use of technology at bedtime and its effects on various health outcomes. They surveyed 207 parents of 8-17 year olds and found that children who watched television at bedtime were significantly more likely to be overweight or obese than those who did not (odds ratio 2.4, 95% CI 1.35-4.18). Similar results were found for children who used a phone at bedtime (OR=2.3, 95% CI 1.31-4.05). There were no significant differences seen with computer or video game use. The authors also looked at sleeping behaviour and found a significant relationship between average hours of sleep and bedtime use of television (P=0.025), phone (P<0.001), computer (P<0.001), and video games (P=0.02). Further analysis showed that children who used various technologies were also more likely to be tired in the morning, less likely to eat breakfast, and more likely to text during the middle of the night. The authors recommend setting up ‘tech-free’ zones and making sure that devices are charged outside of the child’s bedroom.
Of course, this study only shows an association – it may be that some children have difficulty getting to sleep and so turn to technology in order to help them drift off. Meanwhile, the study is subject to reporting bias from the self-reported surveys of the parents, and so further studies are needed.
— Peter Chilton, Research Fellow
- GSMA report. https://www.gsma.com/publicpolicy/wp-content/uploads/2012/03/GSMA_Childrens_use_of_mobile_phones_2014.pdf. 2014.
- Heilmann A, Rouxel P, Fitzsimons E, Kelly Y, Watt RG. Longitudinal associations between television in the bedroom and body fatness in a UK cohort study. Int J Obes. 2017; 41: 1503-9.
- Fuller C, Lehman E, Hicks S, Novick MB. Bedtime Use of Technology and Associated Sleep Problems in Children. Glob Pediatr Health. 2017.
- Schmerler J. Q&A: Why Is Blue Light before Bedtime Bad for Sleep? Scientific American. 01 September 2015.