Sustained, vigorous exercise may be more
effective than lower-intensity activity in
helping children avoid obesity and stay fit,
a new study shows.
Both obesity and poor cardiovascular fitness
are growing problems among children worldwide,
Dr. Michael Sjostrom of the Karolinska Institute
in Huddinge, Sweden and colleagues note. Physical
activity is proven to fight both of these
epidemics.
Evidence is mounting that more intense activity
may be more effective in preventing excess
weight gain, they add.
To investigate how the amount and intensity
of activity might be related to obesity and
fitness in kids, the researchers looked at
780, 9- and 10-year-old children, measuring
their activity levels over four consecutive
days using a device called an accelerometer.
The study is published in the American Journal
of Clinical Nutrition.
The children who engaged in vigorous physical
activity for more than 40 minutes daily had
less body fat than those who were this active
for just 10 to 18 minutes a day, and also
had higher cardiovascular fitness, the researchers
found.
There was no association between the total
amount of a child's daily physical activity
and his or her levels of body fat, but kids
who were active for a longer amount of time
each day did have greater cardiovascular fitness.
"Our...results suggest that vigorous-intensity
physical activity may have a greater impact
in preventing obesity in children than lower
physical activity intensity levels, whereas
both total and at least moderate to vigorous
physical activity may improve children's cardiovascular
fitness," the researchers conclude.
They acknowledge that vigorous activity may
be more difficult for overweight and obese
children and teens. The doctors suggest that
these individuals begin with moderate activity
and gradually increase both the intensity
and amount of exercise.
SOURCE: American Journal of Clinical Nutrition,
August 2006.
