Seasonal variation in physical activity, sedentary behaviour and sleep in a sample of UK adults

Background: Physical activity (PA), sedentary behaviour (SB), sleep and diet have all been associated with increased risk for chronic disease. Seasonality is often overlooked as a determinant of these behaviours in adults. Currently, no study has simultaneously monitored these behaviours in UK adults to assess seasonal variation. Aim: The present study investigated whether PA, SB, sleep and diet differed over season in UK adults. Subjects and methods: Forty-six adults (72% female; age -41.7 +/- 14.4 years, BMI -24.9 +/- 4.4 kg/m 2) completed four 7-day monitoring periods; one during each season of the year. The ActiGraph GT1M was used to monitor PA and SB. Daily sleep diaries monitored time spent in bed (TIB) and total sleep time (TST). The European Prospective Investigation of Cancer (EPIC) food frequency questionnaire (FFQ) assessed diet. Repeated measures ANOVAs were used to identify seasonal differences in behaviours. Results: Light-intensity PA was significantly higher in summer and spring (p<0.001). SB and TIB were significantly higher in winter (p<0.01). There were no seasonal variations detected in moderate-vigorous PA, TST or diet (p>0.05). Conclusions: Findings support the concept that health promotion campaigns need to encourage year-round participation in light intensity PA, whilst limiting SB, particularly during the winter months.