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Sleep, Screen use, Nutrition and Activity using Photo Images in Teens

The SNAP IT project is an observational study aimed to measure sleep, screen use, nutrition and physical activity in teenagers through the use of automated cameras.

Many New Zealand teenagers do not get enough sleep. Research has shown that the negative effects of poor sleep are widespread, influencing weight, school performance, emotional and behavioural problems, risky behaviour, physical activity and dietary intake. There is evidence for a strong relationship between a lack of sleep and obesity in children and adolescents, but the mechanisms explaining this relationship are unclear. Our research aims to assess the relationship between pre-bed time behaviours and their effect on sleep outcomes.

The results of the SNAP IT study will help us understand how pre-bed time screen use, physical activity and food intake may impact sleep in adolescents. Ultimately such findings can be used to develop appropriate interventions to improve sleep in teenagers, which will have a positive impact on both short- and long-term health and development.

Using new technologies

The SNAP IT study incorporates various novel technologies to complement traditional methods in public health research.

Wearable cameras

The study is recruiting 200 teenagers (aged 13-17 years) to wear automated cameras from 5pm until bed-time. These cameras have the potential to capture various lifestyle behaviours (such as eating, screen time and physical activity), as well as the environmental context of these behaviours.

The captured images will give insight into the quantity of screen use, types of screens, use of multiple screens and the context of use (e.g. television in the bedroom) in an adolescent population. Coupled with actigraphy, which will measure sleep outcomes, the cameras offer an objective way to understand how evening screen use might impact sleep.


An electromyogram (EMG) is a small sensor that can be placed on the cheek to measure chewing or swallowing. Combining the captured pictures of foods with a traditional diet-recall and measurements of a wireless EMG will help the research team to understand the relationship between the timing of food intake, types of food groups consumed, snacking behaviours and caffeine intake on sleep outcomes.


Galland, B. C., Gray, A. R., Penno, J., Smith, C., Lobb, C., & Taylor, R. W. (2017). Gender differences in sleep hygiene practices and sleep quality in New Zealand adolescents aged 15 to 17 years. Sleep Health, 3(2), 77-83. doi: 10.1016/j.sleh.2017.02.00


  • Dr Smith is funded by a Postdoctoral Research Fellowship, Health Sciences, University of Otago
  • Running expenses for the project: Department of Women's and Children's Health Research Committee
  • UORG


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