Biology Reference
In-Depth Information
The energy cost of activities in children and adolescents of tropical coun-
tries tended to be lower in comparison to their counterparts living in tem-
perate countries. Where data were available for similar activities in both
tropical and temperate countries, the mean energy costs (or PAR) were
lower in the tropics. For example, the PAR for sitting activities in French
boys (PAR
was higher than in Malaysian boys (PAR
¼
1.11) (
Poh et al., 2003
)
. For
standing quietly, the energy cost was higher among Malaysian boys (1.80,
16-17 years old) compared to French boys (1.42, 14-16 years old)
(
Vermorel et al., 2002
); however, it must be noted that the Malaysian boys
in this case were older than their French counterparts.
The energy cost of physical activities for boys were always lower than
girls when expressed in absolute values (kcal/min). As shown in
Table 2.2
, the same can be said when the energy cost is expressed in mul-
tiples of BMR, otherwise known as PAR; however, there are certain activ-
ities in which the opposite is true. Previous studies have shown similar
findings when comparing between the sexes among children and adolescents
(
Torun, 1990
).
Table 2.2
also shows that the energy costs for physical activ-
ities among overweight and obese children and adolescents were generally
higher than those who were of normal weight. These findings were similar
to results reported by
Maffeis, Schutz, Schena, Zaffanello, and Pinelli (1993)
among obese and nonobese prepubertal children in Italy. In terms of age,
older adolescents appeared to have higher energy costs for similar activities
compared to their younger counterparts
(
Poh et al., 2003
).
One could argue that the above studies are not strictly comparable
because of differences in methodologies employed, the lack of standardiza-
tion in the activities performed, and the small number of children who par-
ticipated in the studies. Therefore, well-designed, standardized studies must
be conducted to confirm if there are differences in the energy cost of activ-
ities for children and adolescents from differing geographic, ethnic, socio-
economic or nutritional backgrounds in the tropics. Most of the studies
were conducted in controlled laboratory environments; therefore, free-
living conditions also should be taken into consideration in future studies.
Research on the energy cost of activities in the tropics is scarce and most
of the data are old (reported between 1923 and 1986) and had already been
compiled by
Torun (1990)
.
Our efforts to search for and report on recent
studies could not locate any published data from other tropical countries
apart from our own data collected in Malaysia. Generally, there are less data
reported for girls than boys, and most countries in the tropics still lack the
¼
