Biology Reference
In-Depth Information
resources and infrastructure to conduct EE studies. Sometimes, available data
were not released for public use or were not published. There is clearly a
need for more studies on the energy cost of activities in a wide range of
age groups, ethnicities, and in both tropical and temperate countries to allow
for comparison among regions of the world. In addition, the scope of activ-
ities to be measured needs to be widened to include classroom activities,
sports and games, household chores, and other tasks commonly performed
by children and adolescents in the tropics.
6. IMPLICATIONS OF PA, PF, AND ENERGY
COST ON OBESITY IN THE TROPICS
6.1. PA and obesity
Current evidence clearly indicates that obesity and physical inactivity are
two important health issues among children and adolescents. In recent
decades, many studies have been conducted to determine the possible rela-
tionships between PA and obesity; however, to date, this relationship has not
been extensively studied, particularly among these young populations in
tropical countries.
Evidence from numerous studies conducted in different countries in the
tropics consistently suggests that obesity is associated with a reduced level of
PA. Studies in Hong Kong (
Yu et al., 2002
)
and the Kingdom of Tonga
(
Smith, Phongsavan, Havea, Halavatau, & Chey, 2007
)
reported that a higher
level of PA participation was associated with a reduced likelihood of being
overweight among adolescents in these countries. Similar findings also have
been reported by
Ramachandran et al. (2002)
and
Dancause et al. (2012)
,
in which low PA was associated with overweight among urban adolescents.
Bharati et al. (2008)
also observed that adolescents who participated in less
than 30 min of outdoor games were found to have an increased risk of being
overweight or obese. This finding aligns with the findings of two other lon-
gitudinal observational studies, which concluded that increased PA could be a
protective factor for the relative weight and fatness gain across childhood and
adolescence (
Must & Tybor, 2005; Reichert, Menezes, Wells, Dumith, &
Hallal, 2009
). In addition, another recent cross-sectional study by
Rezali
et al. (2012)
revealed that PA accounts for approximately 21% of the variations
in body weight status of adolescents in Malaysia (Selangor).
In addition to low levels of PA, sedentary behavior also contributes to the
increased overweight and obesity rates in children and adolescents.
According to
Hong (2005)
,
time spent watching television during the
