Seasonal variations in lifestyle behaviours and their relationship with indicators for poor health
2013-02-13T16:08:21Z (GMT) by
The increasing evidence of associations between physical activity, sedentary behaviour, sleep duration and diet and both immediate and long term health implications is of public health concern. There is a need to further our understanding of the patterns of these behaviours and how they affect poor health indicators individually and simultaneously. This thesis aims to advance the current literature by investigating associations between multiple lifestyle behaviours and indicators for poor health and identifying patterns of physical activity, sedentary behaviour, sleep duration and dietary intake. Anthropometric measurements and bioelectrical impedance analysis were collected from 72 UK adults. These participants were asked to wear an ActiGraph GT1M accelerometer to objectively measure their physical activity and sedentary behaviour across 7 consecutive days. Over these 7 days, participants also completed a self-report daily sleep diary and a food frequency questionnaire. Participants were asked to complete these measurements at 4 different time points across the year in order to capture these behaviours over each season; 46 participants completed all 4 seasons. Using the data collected from the 72 participants who completed at least 1 season, regression analyses were conducted to identify associations between lifestyle behaviours and indicators for poor health. Repeated measures ANOVAs were conducted on data from 52 participants who provided the full 7 days of data during their initial measurement period to assess day of the week variations in physical activity, sedentary behaviour and sleep patterns. Repeated measures ANOVAs were also conducted on physical activity, sedentary behaviour, sleep and dietary intake data provided by the 46 participants who provided 4 seasons of data to assess seasonal variation. This thesis demonstrated that in a sample of relatively active, UK adults, time spent in moderate-vigorous physical activity and sedentary behaviour had a negative association with BMI and body fat percentage, increased time spent in moderate-vigorous physical activity was also associated with decreases in waist circumference. Light intensity physical activity had a positive association with BMI, body fat percentage and diastolic blood pressure. There were significant day of the week variations in light intensity physical activity, sedentary behaviour and time spent in bed, with light intensity physical activity and time in bed being significantly higher on a Sunday, whilst sedentary behaviour was significantly lower on a Sunday in this sample of UK adults. In addition to day of the week variations, there were seasonal variations in light intensity physical activity, sedentary behaviour and time spent in bed and sleep durations (weekdays only). Over the winter months, light intensity physical activity was significantly lower, whilst sedentary behaviour, time in bed and total sleep time was significantly higher. No seasonal variations in time spent in moderate-vigorous intensity physical activity or diet were observed in the present sample. This thesis demonstrates that lifestyle behaviours that have been found to affect health do vary over the week and across different seasons. This research has implications for surveillance studies which estimate these behaviours at one time point throughout the year, and also for interventions aimed at improving these behaviours which are implemented at just one time period of the year. Strategies for overcoming barriers to PA under unfavourable environmental conditions will be needed for this to be achieved, in addition to interventions reducing SB, even in the winter months.