Physical Activity, Fitness and the Energy Cost of Activities: Implications for Obesity in Children and Adolescents in the Tropics - Advances in Food and Nutrition Research - page 62

quantifying the amount of PA, as part of the estimation of energy expended,
is necessary and can be performed by assessing the frequency, intensity, dura-
tion, and type of PA.
Over the decades, regular PA has been found to be beneficial and thus
important for the physical, mental, and social health of children and adoles-
cents ( Centers for Disease Control, Prevention (CDC), 2011 ) . Moreover, it
is an accepted norm that regular PA established during the early years, par-
ticularly the period of adolescence, not only protects against physical inac-
tivity in adulthood ( Azevedo, Ara´ jo, Silva, & Hallal, 2007; Hallal, Victora,
Azevedo, &Wells, 2006 ) but also greatly impacts the mortality and longevity
of individuals ( Hills, King, & Armstrong, 2007 ) because people establish
many of their lifestyle choices as they proceed through adolescence.
In spite of these benefits, evidence clearly indicates that PA levels decline
from childhood to adolescence ( Allison, Adlaf, Dwyer, Lysy, & Irving,
2007; Dumith, Hallal, Reis, & Kohl, 2011; McMurray, Harrell, Creighton,
Wang, & Bangdiwala, 2008; Nader, Bradley, Houts, McRitchie, &
O'Brien, 2008 ), and this decrease is more marked among girls than boys
( Allison et al., 2007; Dumith et al., 2011 ) . Nevertheless, there are still rel-
atively few studies or literature on children and adolescents' PA in tropical
countries; furthermore, far less is known about the current PA pattern and its
impact on the health of these populations.
3.2. Global data on PA in the tropics
In addition to body weight status, the GSHS also assessed the PA levels of
adolescents using a standardized questionnaire across countries ( WHO,
2011 ). We have conducted a secondary analysis to estimate the PA patterns
and levels of the adolescents in these tropical countries, and the results are
summarized in Figs. 2.4 and 2.5 . Figure 2.4 presents the percentage of ado-
lescents who were physically active for a total of at least 60 min a day over a
7-day period, while Fig. 2.5 shows the percentage of adolescents who spent
3 or more hours a day in sedentary activities.
Figure 2.4 revealed that Vanuatu had the highest percentage of adoles-
cents (46.7% boys and 45.7% girls) who were physically active for at least
60 min a day during the past 7 days, while Venezuela achieved the lowest
percentage (8.1%) among the 46 tropical countries included in the analysis.
In general, we found that most adolescents in the tropics did not engage in
sufficient amounts of PA, as only 25% of the boys (in more than half of the
countries) and 16.4% of girls (for all countries except India) met the PA