Overall , toddlers tend to exceed the total PA recommendation of 180 min/day ; however , very little of this time is spent at higher movement intensities .
Even with high PA rates , toddlers still engage in substantial ST .
Early experiences in physical activity ( PA ) are important to shape healthy movement behaviours long-term ; as such , it is critical that PA is promoted from infancy , and that detrimental behaviours ( e.g. , prolonged sedentary time [ ST ] ) are minimized .
The purpose of this systematic review and meta- analysis was to examine infants ’ and toddlers ’ movement behaviours across daytime hours .
Relation of Heart Rate and its Variability during Sleep with Age, Physical Activity, and Body Composition in Young Children
Background : Recent studies have cl aim ed a positive effect of physical activity and body composition on vagal tone . In pediatric population s , there is a pronounced decrease in heart rate with age . While this decrease is often interpreted as an age-related increase in vagal tone , there is some evidence that it may be related to a decrease in intrinsic heart rate . This factor has not been taken into account in most previous studies . The aim of the present study was to assess the association between physical activity and /or body composition and heart rate variability ( HRV ) independently of the decline in heart rate in young children . Methods : Anthropometric measurements were taken in 309 children aged 2–6 years .  Ambulatory electrocardiograms  were collected over 14–18 h comprising a full night and accelerometry over 7 days . HRV was determined of three different night segments : ( 1 ) over 5 min during deep sleep identified automatically based on HRV characteristics ; ( 2 ) during a 20 min segment starting 15 min after sleep onset ; ( 3 ) over a 4-h segment between midnight and 4 a.m. Linear models were computed for HRV parameters with anthropometric and physical activity variables adjusted for heart rate and other confounding variables ( e.g. , age for physical activity models ) . Results : We found a decline in heart rate with increasing physical activity and decreasing skinfold thickness . HRV parameters decreased with increasing age , height , and weight in HR-adjusted regression models . These relationships were only found in segments of deep sleep detected automatically based on HRV or manually 15 min after sleep onset , but not in the 4-h segment with r and om sleep phases . Conclusions : Contrary to most previous studies , we found no increase of st and ard HRV parameters with age , however , when adjusted for heart rate , there was a significant decrease of HRV parameters with increasing age . Without knowing intrinsic heart rate correct interpretation of HRV in growing children is impossible
Overall , toddlers tend to exceed the total PA recommendation of 180 min/day ; however , very little of this time is spent at higher movement intensities .
Even with high PA rates , toddlers still engage in substantial ST .
Early experiences in physical activity ( PA ) are important to shape healthy movement behaviours long-term ; as such , it is critical that PA is promoted from infancy , and that detrimental behaviours ( e.g. , prolonged sedentary time [ ST ] ) are minimized .
The purpose of this systematic review and meta- analysis was to examine infants ’ and toddlers ’ movement behaviours across daytime hours .