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 73

Many of the estimates were derived from the energy cost of activities per-
formed by adults and were expressed by unit of body weight; however,
Torun (1990) questioned the validity of such estimates of energy costs.
Rowland, Auchinachie, Keenan, and Green (1987) found that the
weight-related energy cost of exercise is lower in adults than children.
The difference is likely due to physiology-related mechanisms ( Rowland &
Green, 1988 ) . In addition, differences in body height ( Bonen, Heyward,
Cureton, Boileau, & Massey, 1979 ) , body weight, and body composition
( Murray et al., 1993 ) also contribute. It is thus more appropriate to
determine the energy cost of activities in children and adolescents themselves
to derive an accurate estimate of daily EE and recommendations for energy
intake based on this EE would therefore be more appropriate.
TEE includes BMR, resting metabolic rate, the thermic effect of food
and activity energy expenditure (AEE). BMR contributes approximately
60-70% of daily EE ( Ravussin, Lillioja, Anderson, Christin, & Bogardus,
1986 ). The BMR is often used for the calculation of TEE by multiplying
the time spent in various activities by the respective energy cost calculated
based on a BMR multiple (also known as the physical activity ratio, PAR).
The PAR is the ratio that expresses the energy cost of an individual activity
per minute as multiples of BMR ( James & Schofield, 1990 ). The assumption
for using this approach to calculate energy requirements is that it compen-
sates for differences in body weight between individuals. The PAR of activ-
ities can be obtained either by direct measurements or from data in the
published literature.
Published data on the PARs of different activities are available primarily
for Caucasian children ( Ainsworth et al., 1993, 2000; FAO, 1985, 2004;
James & Schofield, 1990 ). Using data from previously published literature,
Torun (1990) compiled the energy cost of physical activities among healthy
children in developing countries. The following section summarizes the
information currently available in the tropics on the energy cost of habitual
activities commonly performed by children.
5.2. Methods of measuring energy cost
EE can be estimated by indirect estimates or by direct measurements of oxy-
gen uptake. Indirect methods include PA questionnaires, pedometers, and
accelerometers ( Kashiwazaki, Inaoka, Suzuki, & Kondo, 1986 ), heart rate
(HR) monitors ( Spurr et al., 1988 ) , and doubly labeled water ( Stager,
Lindeman, & Edwards, 1995 ) . The Douglas bag (DB) technique is the classic