3.1. Daily pattern of EE and TDEE

The minute-by-minute heart-rate method was utilized to follow the EE while children were awake (SPURR and REINA, 1988a) from about 6 a.m. to 8-9 p.m. Since the schoolday in Cali operates on two 5-hour shifts (7 a.m. to 12 p.m. and 1 to 6 p.m.), the data were analyzed by 'school-time' and 'free-time' without regard to whether they were obtained in the morning or afternoon. In Figure 7 they are presented in 30-minute averages, during 5 hours in each category, together with the two and three-way analysis of variance (ANOVA; with repeated measures where appropriate).

Figure 7. Thirty-minute averages of energy expenditure in 6-8, 1012 and 14-16-year-old normal and marginally undernourished Colombian boys and girls during 5 hours of 'school-time' and 'free-time'. Where appropriate, two-way ANOVA is with repeated measures. From SPURR and REINA, 1988a.

There are statistically significant differences in nutritional group (NG) in the youngest children and during the time course of the 5-hour period in school only in the girls. In the repeated measures ANOVA over time (hours), the only significant change occurred during the fall in EE in 14-16-year-old girls during school, and all age groups of girls had significantly lower values than boys.

These data are presented primarily to show the results of a study using minute-by-minute heart-rate measurement. Another kind of application showing the failure of malnourished boys to keep up with their well-nourished counterparts is presented in the article by Torun in this volume (his Figure 6 on p. 348).