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Behaviours across the 24-hour day

Collaborators

Overview

New health guidelines in New Zealand emphasise the importance of accurately measuring the full range of activities that occur across the 24-hour day with the slogan "Sit less, Move more, Sleep well".

However, collecting and analysing 24-hour movement patterns is complicated. To date, a tool that accurately measures all relevant behaviours in the free-living environment does not exist. Actigraphs provide the best measure at present. Considerable problems remain, particularly regarding their ability to discriminate between sleep and other sedentary behaviours such as television viewing or lying quietly awake. Analysing these data is also complicated because of the fixed 24-hour window—if one activity goes up (such as sleep) then another has to decrease (such as sedentary time), meaning that compositional data analysis techniques need to be used.

This study incorporates actigraphs to measure both sleep and physical activity to see if we can accurately assess 24-hour movement patterns (sleep, sedentary time, physical activity) in children aged 8 to 16 years. Specific objectives are to:

  • validate the use of multisite actigraphs as an accurate measure of sleep and wake against polysomnography
  • determine the validity actigraphs in correctly classifying a range of physical activities in both laboratory and free-living conditions
  • develop machine learning algorithms for correctly identifying 24-hr movement patterns