Investigating heart rate responses of children to active travel: a mixed effects modeling analysis

The active travel concept has gained recognition as an effective method to enhance physical activity in children's everyday mobility. Yet, there is a notable gap of quantitative evidence on its direct impacts, especially regarding physiological outcomes that can concretely demonstrate its influences on physical intensity and overall health of children.

This study investigates the effects of active travel on children, focusing on trip-level physiological responses, specifically heart rate. Through a mixed survey design, we obtained a repeated-measures dataset from a cohort of 73 children (average age 13) across three Austrian secondary schools, each observed for 7 days. By applying mixed effects modelling approach, both fixed and random effects to children's heart rates were explored.

According to results from developed mixed linear models (maximum R² = 0.22), it revealed a significant positive association between active travel mode(s) engagement and heightened physiological responses (Low, Medium and High active level of trip compare to None: β = 1.81, 5.01 and 8.34, t-value = 4.70, 10.29 and 21.34), indicating that increased usage of active travel modes led to elevated heart rate values. Additionally, subjective perceptions also played an important role in influencing children's physiological responses. Feelings of exhausted, anxiety, and stress contributing to a higher heart rate (β = 14.79, 16.69 and 1.99, t-value = 20.42, 5.67 and 3.0), while unhappiness was associated with a lower heart rate (β = -5.96, t-value = -14.62). Effects of social interactions were also found during the trip. The presence of adults was associated with a calming effect (β = -1.92, t-value = -5.72), whereas solo travel resulted in lower heart rate compared to travel with peers (β = -1.95, t-value = -6.59).

Our article innovatively employs mixed survey methods and heart rate data to quantitatively demonstrate the positive association between engagement in active travel modes and heightened physiological responses in children, elucidating the intricate interplay of subjective perceptions and social interactions during trips, thus offering valuable insights into the health implications of active travel at a trip level. Future research will keep on leveraging survey and experimental methods.