Impact of a Single Exercise Bout on Energy Expenditure and Spontaneous Physical Activity of Obese Boys

Abstract

The main objective of the present study was to determine whether a structured, laboratory-based exercise task would modify the energy expenditure (EE) and the pattern of spontaneous physical activity (PA) of obese boys on the day of an exercise laboratory visit and on the following day. Fourteen 10- to 15-y-old moderately obese (36.6+/-3.3% fat) boys volunteered. They each had three laboratory visits, I wk apart. In one visit, they performed a strenuous 50-min cycling task; in another, a 30-min medium-intensity cycling task; and in another (which served as placebo), they did not exercise. PA was monitored the day before (d 1), during (d 2), and after (d 3) each laboratory visit by use of a heart rate monitor and a 12-h recall interview. EE was calculated from minute-by-minute heart rate and each child's predetermined relationship between oxygen uptake and heart rate. EE and PA were analyzed from 1300 to 1900 h each day using 15-min intervals. EE tended to decrease (p < 0.087) in the afternoon of all d 2 compared with d 1, and it increased on d 3 after the medium-intensity exercise (p < 0.0005). EE during d 2 and 3 combined, compared with d 1, decreased after the high-intensity exercise (534.2 versus 564.3 kJ/h, p < 0.05). It increased after the medium-intensity exercise (561.8 versus 526.7 kJ/h, p = 0.052) and was not affected after the placebo visit (589.4 versus 574.3 kJ/h). Time spent outdoors was consistently reduced on the day of laboratory visit compared with the day before and after the visit, regardless of the contents of intervention. In conclusion, a single laboratory visit is followed by a reduction in EE and PA on the day of intervention. However, its effect on EE the following day may be dose dependent: medium-intensity exercise induces an increase in EE, but high-intensity exercise causes a decrease in EE. One implication is that intervention by physical training should employ medium-intensity exercise to enhance the EE of obese boys.

The ActivityStat Hypothesis

“…The majority of studies investigated compensation in adults [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] however eight studies recruited children [18,28,[44][45][46][47][48][49] and five the elderly [27,[50][51][52][53] . Only one study [18] specifically aimed to test the activitystat hypothesis.…”

“…The frequency and duration of the exercise stimulus ranged one day [29] to 4 years [48] and outcome measures included doubly labeled water (n=10), accelerometry (n=13), heart rate monitoring (n=7), resting metabolic rate (n=13), indirect 18 of 35 calorimetry (n=2), pedometry (n=1), subjective recall questionnaire (n=11) and activity-related time index (n=2). ***Insert Table I about here*** Thirteen of the 28 papers reported clear evidence of compensation [27,31,32,37,39,43,44,[46][47][48][49][51][52][53] , with a further three studies reporting mixed results; for example evidence of compensation in females but not males [37] , with high intensity exercise only [46] or in 'responders' (those that achieved the expected amount of weight loss) only [35] . Critical appraisal scores ranged from three [45] to seven [32,40,51,52] out of a possible total of eight.…”

“…Examples include use of subjective recall questionnaires when investigating physical activity [44,45] , approximation of total energy expenditure based on heart rate telemetry [36,41,46,53] , and subjective and factorial methods for estimating total energy expenditure [53] . While heart rate is considered a feasible method for the estimation of total energy expenditure [57] , it must be acknowledged that doubly labeled water is currently the gold standard method of measurement.…”

Potential causes, mechanisms, and implications of post exercise hypotension

“…However, for those not involved in regular activity, a single session of moderate intensity often induces a decrease in physical activity and exercise energy expenditure in the hours post exercise. 80 We have recently completed a study in a controlled setting using continuous, indwelling blood pressure monitoring and tracked the blood pressure changes during a standardised protocol of mild exercise and activities of daily living following both rest and a bout of cycle ergometry. We showed a significant decrease in SBP, DBP, and mean arterial pressure (MAP) to the end of the 70-min monitoring period, with no trend towards returning to baseline values when preceded by prior exercise.…”

Physical Activity, Energy Expenditure and Intake in 11 to 12 Years Old Japanese Prepubertal Obese Boys.

“…daily EE in children (Yamamoto et al, 1983;Kriemler et al, 1999). According to Waxman and Stunkard (1980), although differences were not found in EE at school, EE of obese children after school was significantly lower than that of nonobese children.…”