Exploring Associations Between Sleep, Physical Activity And Glycaemic Control

Background:

Physical activity and sleep are lifestyle behaviours associated with health and well-being. However, few studies have examined a potential interaction among the two behaviours and most investigations of these relationships relied on self-report. Wrist accelerometers can capture the whole 24-hour physical behaviour profile but limited data on the validity of these to measure sleep exists.

Aims:

1) Assess the criterion validity of an automated sleep detection algorithm for common research-grade raw acceleration accelerometers worn on both wrists against polysomnography.

2) Establish comparability of sleep outcomes between common research-grade raw acceleration accelerometer brands, wrist placements, and sleep log condition (with/without) in free-living setting.

3) Examine the effect of exercise on sleep and the bidirectional associations with accelerometer-assessed physical activity in men with obesity.

4) Examine associations between chronotype, accelerometer-assessed sleep duration and physical activity, and short-term glycaemic control in people with type 2 diabetes.

Key findings:

1) The automated sleep detection algorithm applied to three commonly used accelerometers, worn on either wrist, provides comparable estimates of sleep compared to polysomnography but a poor measure of wakefulness during the sleep period.

2) At group level, sleep data were comparable from different accelerometers worn on either wrist irrespective of the accelerometer brand when the sleep log was not used.

3) An exercise intervention had a chronic but not an acute effect on sleep duration. Day-to-day, more physical activity predicted earlier timing of sleep onset, but worse sleep quality during the following night and vice versa.

4) Being a morning or evening chronotype was not associated with short-term glycaemic control in adults with type 2 diabetes. Achieving optimal sleep duration and increasing moderate-to-vigorous physical activity could be important for daily glucose regulation.

Conclusions:

Wrist accelerometry can be used to assess sleep and provides concurrent measures of physical activity and sleep. Evidence of an inter-relationship between the two behaviours and their association with glucose profiles highlights the importance of measuring the full 24-hour day of physical behaviours in future studies.