The aim of this study was to provide objective data on the cardiopulmonary fitness and physical activity patterns of Northern Irish postprimary schoolchildren. Forty-five children (23 boys, 22 girls), ages 11-16 years, took part in this study. Each child performed a laboratory test of peak aerobic power (PVO2) and had his/her heart rate monitored for up to 4 school days. The mean values of PVO2 in both boys and girls were in keeping with previous literature. No significant difference was observed between boys and girls in terms of total activity (>50% PVO2), but boys engaged in significantly more vigorous activity (>70% PVO2 than girls did (p<0.05). Younger boys engaged in significantly more vigorous activity than both older boys (p<0.01) and younger girls (p<0.05). A significant negative correlation was found between age and total activity for boys (r= −0.476, p<0.05), but not for girls (r= -0.173, n.s.). The surprisingly low levels of physical activity on the part of older children of both sexes are a cause for concern.
Chris Riddoch, Craig Mahoney, Niamh Murphy, Colin Boreham and Gordon Cran
Trynke Hoekstra, Colin A. Boreham, Liam J. Murray and Jos W.R. Twisk
It is not clear what the relative contribution is of specific components of physical fitness (aerobic and muscular) to cardiovascular disease (CVD) risk. We investigated associations between aerobic fitness (endurance) and muscular fitness (power) and CVD risk factors.
Data were obtained from the Young Hearts project, a representative sample of 12- and 15-year-old boys and girls from Northern Ireland (N = 2016). Aerobic fitness was determined by the 20-m shuttle run test, muscular fitness by the Sargent jump test. CVD risk factors included sum of skinfolds, systolic and diastolic blood pressure, serum total cholesterol (TC), HDL cholesterol, and TC:HDL ratio. Several linear regression analyses were conducted for 4 age and gender groups separately, with the risk factor as the outcome variable.
Significant associations between aerobic fitness and a healthy CVD risk profile were found. These observed relationships were independent of power, whereas the (few) relationships between muscular fitness and the risk factors were partly explained by endurance.
Tailored, preventive strategies during adolescence, incorporating endurance rather than power sports, could be encouraged to help prevent CVD. This is important because existing studies propose that healthiness during adulthood is founded on healthiness in adolescence.
David P. McKee, Colin A.G. Boreham, Marie H. Murphy and Alan M. Nevill
Activity measurement using a uniaxial pedometer was validated against behavioral observation using the Children’s Activity Rating Scale (CARS) in 30 three- to four-year-old children in a nursery school setting. Correlations were calculated for individual children, whereas the relationship for the total group was investigated using multilevel linear regression. The mean counts for boys and girls for the Digiwalker™ were 66.8 (± 64.0) and 47.4 (± 61.3; p < .01) steps per 3 minutes, respectively, whereas the mean CARS scores for boys and girls were 1.8 (± 0.6) and 1.6 (± 0.6; p < .01), respectively. Within-child correlations for CARS versus Digiwalker counts ranged from 0.64 to 0.95 with a median value of 0.86, whereas the multilevel analysis provided strong evidence of a relationship between CARS and Digiwalker (all p < .001). Data from the current study show that gender differences in physical levels exist in very young children and support the utility of the Digiwalker pedometer for assessing physical activity in this age group.
Elaine M. Murtagh, Colin Boreham, Alan Nevill, Gareth Davison, Tom Trinick, Ellie Duly, Mawloud El-Agnaf and Marie H. Murphy
Markers of inflammation are emerging as novel indices of cardiovascular risk. These markers have been shown to alter acutely after intense exercise; however, the effects of more moderate intensity exercise in healthy individuals is not known. Walking forms a cornerstone of physical activity promotion, so the inflammatory response to this exercise merits investigation. This study evaluated the effects of a 45-min walk on C-reactive protein (CRP) and interleukin 6 (IL-6), in sedentary, overweight men.
Fifteen men (49.7 ± 5.9 y) walked for 45 min at 60 to 70% of predicted maximum heart rate. Fasted blood samples were taken prior to and immediately 1 hr and 24 h post-walk.
IL-6 decreased from 1 h post-walk to 24 h post-walk (P < 0.01). No significant changes were observed in CRP.
These findings suggest that 45 min walking at 60 to 70% HRmax-p causes a decrease in IL-6 24 h post-exercise, but does not evoke a significant response in CRP levels.
Chris Riddoch, Dawn Edwards, Angie Page, Karsten Froberg, Sigmund A. Anderssen, Niels Wedderkopp, Søren Brage, Ashley R. Cooper, Luis B. Sardinha, Maarike Harro, Lena Klasson-Heggebø, Willem van Mechelen, Colin Boreham, Ulf Ekelund, Lars Bo Andersen and The European Youth Heart Study Team
The aim of the European Youth Heart Study (EYHS) is to establish the nature, strength, and interactions between personal, environmental, and lifestyle influences on cardiovascular disease (CVD) risk factors in European children.
The EYHS is an international study measuring CVD risk factors, and their associated influences, in children. Relationships between these independent factors and risk of disease will inform the design of CVD interventions in children. A minimum of 1000 boys and girls ages 9 and 15 y were recruited from four European countries—Denmark, Estonia, Norway, and Portugal. Variables measured included physical, biochemical, lifestyle, psychosocial, and sociodemographic data.
Of the 5664 children invited to participate, 4169 (74%) accepted. Response rates for most individual tests were moderate to high. All test protocols were well received by the children.
EYHS protocols are valid, reliable, acceptable to children, and feasible for use in large, field-based studies.