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The majority of youth of all ages fail to meet international guidelines for the level of activity required for optimal health. In addition, physical activity is known to decline throughout adolescence, reducing by approximately 5% per year from the age of twelve. This study (PEACH: Personal and Environmental Associations with Children’s Health) investigated possible modifiable determinants of children’s physical activity behaviour in 1307 children measured in their final year of primary school, and again 1 year later (n=958) in their first year of secondary school. A novel component of the study was to use personal GPS receivers to measure how much physical activity is accumulated during the journey to school, and to describe the relationship between time outdoors and physical activity level.
The aim of the current study was to measure the same children again in mid adolescence to explore whether physical activity changes with increasing age, whether travel mode was associated with any change, and to explore associations between greenspace, physical activity and stress, measured by self report and objectively by salivary cortisol.
Data were collected during secondary school year 10, when participants were aged 14-15 years. Adolescents who had previously taken part in PEACH were re-contacted within their tutor groups at secondary school. Written informed consent was obtained from a parent/guardian of all children who took part in the study. Physical activity was measured for 7 days using an accelerometer (Actigraph GT1M), and spatial location was measured with a personal GPS receiver. Time-matched accelerometer and GPS data were visualised in a Geographical Information System (GIS). Self-reported stress was assessed by questionnaire and cortisol was measured in saliva samples collected from participants over the course of 1 day (on waking, thirty minutes later and just before bed). Neighbourhood greenspace within 800m of the residential home location of each child was determined from Ordnance Survey datasets.
All pupils who had taken part in PEACH in their primary school and where secondary school location was known (n=1055) were invited to participate. Of these, 586 (55.5%; Male n=270 (46.1%)) consented and attended measures. Physical activity declined between the ages of 12 and 15 years by approximately 13.8% (556.4 (181.8) vs 479.3 (167.8) accelerometer counts per minute; p<0.001). Participants who walked were significantly more active overall and accrued more daily MVPA than those travelling by car (508.7 (156.7) vs 400.0 (161.5) cpm, p<0.001; 61.8 (21.7) vs 41.5 (22.1) minutes of MVPA, p<0.001 respectively), but physical activity declined in both groups with increasing age. Spatial segmentation in a GIS found that the average journey time to school was 19.0 (8.7) minutes, during which 13.7 (7.0) minutes of MVPA were accumulated, similar to values at 12 years of age.
We found that perceived stress was higher in neighbourhoods of lower social class, and identified a clear sex difference in both perceived and measured stress, with girls having higher values than boys. However, we could find no association between either self-reported or objective stress measures, physical activity or proximity to greenspace.
Active travel to school is important for young people’s physical activity. The segmentation data suggest that walking the return journey to and from school could contribute approximately 43% of daily MVPA in adolescents, and those who walked to school were more active than car users. Whilst it is generally believed that greener environments are beneficial for health, and in particular aspects of mental health, this study does not provide supporting evidence for a relationship with stress in this sample of adolescents.
The majority of youth of all ages fail to meet international guidelines for the level of activity required for optimal health. The WCRF-funded PEACH (Personal and Environmental Associations with Children’s Health) project aimed to identify factors that were associated with physical activity in youth and which could be changed to increase physical activity. The first phase of the study measured 1,307 children in their final year of primary school, and 958 of these children 1 year later in their first year of secondary school. The study aimed to explore whether physical activity declined over the primary-secondary school transition, since this has been proposed to be an important transitional time in children’s behaviours. A novel component of the study was to use personal GPS receivers to measure how much physical activity is accumulated during the journey to school, and to describe the relationship between time outdoors and physical activity level.
This study found that that in the sample overall, physical activity did not decline between primary and secondary school, but how children travelled to school was an important factor, with those who continued to walk to school increasing their daily physical activity, due to walking longer distances, whilst those moving to motorised travel had significantly lower daily physical activity. Analysis of GPS data showed that walking to school made an important contribution to young people’s physical activity, contributing up to one-third of daily physical activity. In addition, the GPS data showed that being outside was strongly associated with higher activity and that activity in green spaces such as parks was higher than elsewhere.
The aim of the current project was to measure the children again in mid-adolescence to explore whether:
All pupils who had taken part in PEACH in their primary school and where secondary school location was known were invited to participate. Of these, 586 consented and attended measures. Participants wore activity monitors and GPS receivers for 1 week, provided saliva samples for cortisol assessment three times on one day and completed questionnaires to measure travel mode and stress.
Physical activity had declined between ages 12 and 15 years by approximately 14%, and whilst participants who walked to school were still more active than those travelling by motorised transport, both car/bus users and walkers showed similar reductions in physical activity with age. GPS data continued to show that greater time spent outdoors was associated with higher overall physical activity, and that the contribution of walking to school to daily physical activity was essentially unchanged between 12 and 15 years of age. No associations were found between proximity to greenspace and levels of stress.
Active travel to school is important for young people’s physical activity. Those who walk to school are more active than car users, but show a similar age related decline in physical activity. Whilst it is generally believed that greener environments are beneficial for health, and in particular aspects of mental health, this study does not provide supporting evidence in this sample of adolescents.