Even healthy children as young as nine-years-old can start to show an
increased risk of future heart problems if they are physically inactive,
according to a study in the May issue of Acta Paediatrica.
A team of researchers from Sweden and Denmark studied 223 children - 123
boys and 100 girls - with an average age of 9.8 years, assessing their
physical activity levels over four days.
They found that the children who were more physically active had a lower
composite risk factor score for cardiovascular disease (CVD) than the children
with lower amounts of moderate to vigorous physical activity and vigorous
physical activity.
"It is well known that physical inactivity in adults is associated with a wide
range of diseases and all causes of death" says lead author Dr Tina Tanha
from the Department of Clinical Sciences at Skane University Hospital in
Malmo, Sweden.
"We believe that our study now demonstrates a clear clinical association
between physical inactivity and multiple CVD risk factors in children. It reveals
that up to 11 per cent of the variance in composite CVD risk factor scores in
the children could be explained by differences in their physical activity."
The children wore an accelerometer strapped to an elastic waist belt for four
consecutive days to measure physical activity levels, using parameters set by
two large accelerometer studies. Children were only included in the study if
they wore the belt for a minimum of eight hours a day for three days. They
also underwent tests for various CVD risk factors, including blood pressure,
resting heart rate, fitness and body fat.
Key findings included:
-The children's average body mass index was 17.5 for the girls and 17.4 for
the boys.
-The boys were significantly more physically active than the girls, with
higher levels of general physical activity (746 mean counts per minute
versus 620), moderate to vigorous physical activity (45 minutes versus 35
minutes) and vigorous physical activity (15 minutes versus 11 minutes).
-There were no significant differences between the genders when it came to
systolic and diastolic blood pressure, mean arterial pressure and pulse
pressure. However the resting heart rate was significantly higher in the girls
(85 versus 80 beats per minute).
-The boys had lower total body fat mass than the girls (6.3kg versus 8.3kg)
and lower percentage body fat (16.2 per cent versus 22.6 per cent), but a
higher peak oxygen uptake (41.7mL/min/kg versus 35.7).
-Vigorous physical activity accounted for ten per cent of the variance in the
accumulated cardiac risk scores and moderate to vigorous physical activity
accounted for eight per cent of the variance. The results were similar for
boys and girls.
-But there was a difference when it came to general physical activity. This
accounted for 11 per cent of the variance in the boys, but showed no
significant variance in the girls.
"Previous research into CVD risk factors in children have focused on quite
specific single risk factors, but our study covers multiple risk factors" explains
Dr Tanha.
"Our results show a significant association between low levels of activity and
high composite risk factors for CVD, even in young children. Much of the
association was driven by body fat measurements and oxygen intake.
"This is important because the accumulation of these risk factors, if started in
early childhood and sustained over a long period, is believed to have greater
impact on CVD and mortality than one single risk factor."
Notes
Lack of physical activity in young children is related to a higher composite risk factor score
for cardiovascular disease. Tanha et al. Acta Paediatrica. 100, pp717-721. (May 2011).
DOI: 10.1111/j.1651-2227.2011.02226.x
Source:
Wiley-Blackwell