Implications for practice and research

• Physical activity among children can be increased by reducing screen media usage. Parents and health professionals should support children to use their screen time wisely.

• Future research must continue to investigate the link between media usage and sleep.

Context

There is a growing body of evidence linking sedentary behaviour with negative health effects.1 Excessive screen time is associated with obesity2 and mental illness,3 but the evidence is weak as to whether there is a causal relationship between screen time and health effects. In this study, Pedersen et al 4 investigate whether reducing screen use in both children and parents affects physical activity and sleep.

Findings

The children in the intervention group reduced their screen time by an average of 45 min per day, compared with the control group who reduced their screen time by an average of 1 min. The mean difference between the intervention group and the control group of children’s non-sedentary time was 45 min favouring the intervention group. No significant differences were found on adult physical activity. No significant differences for sleep outcomes were found for either children or adults.

Commentary

Although removing screens was enough to increase the children’s physical exercise, it had no effect on their parents. This leads to two lines of questions which should be investigated further in future studies: How do adults spend their screen-free time and why? From an exercise perspective, it might have been overly optimistic to expect adults to create new habits during a short period of time and without support. Motivation and access to exercise are significant here. In addition, physical exercise might not have been parents’ first choice when faced with screen-free time to fill. They may have engaged in activities that were personally meaningful yet sedentary, such as reading, household chores, meeting friends, creating art and so on. Future studies should investigate how time was spent and evaluate the effects of reduced screen time on parameters of mental health, such as life satisfaction.

No sleep effects were found as a result of limiting recreational screen media usage. This might also be due to the sample, since it was not based on people with sleeping problems, and it is difficult to measure improvements among those who already sleep well. At baseline, objective measures of sleep showed that the children slept for 9 hours on average (± 63 min), and adults for 7 hours (± 54 min), which is in line with general sleep duration recommendations for adults and school aged children.5 For future research, it would be of interest to conduct the same study among people with insomnia and/or subjectively short sleep duration. It would also be of interest to measure subjective ratings of sleep quality, when people’s judgement of their sleep quality is often based on feelings of fatigue, and mood on awakening, and during the day.6