Metabolic and cardiorespiratory responses to maximal and submaximal exercise in eutrophic and stunted girls

Abstract

OBJECTIVE: The metabolic and cardiovascular responses of eutrophic girls and girls who underwent early undernutrition, were examined during physical exercise, in order to verify whether previous undernutrition could, in addition to cause a deficit in the children's height, and limit their functional capability to perform a maximal and submaximal exercise in an ergometric bicycle. SUBJECTS: Our sample was composed of 24 girls, of which 12 were eutrophic, with 9.13 +/- 0.79 years (mean +/- s.d.), 27.64 +/- 3.64 kg of body weight, and 131.31 +/- 6.04 cm in height. The 12 early undernourished girls were 9.75 +/- 1.1 years old, 25.16 +/- 2.33 kg, and 125.06 +/- 3.9 cm high. MEASUREMENTS: The method included clinical evaluation and ergo-spirometric test on an ergometric bicycle, from which all the metabolic and cardiac-respiratory variables were obtained and analyzed. The test protocol was an initial two minutes period with 25 watts, followed by increments of 15 watts every two minutes, until exhaustion. RESULTS: Analysis of the results of the test of maximal effort did not reveal significant differences between eutrophic (E) and early undernourished (UN) girls in any of the variables: VO2max expressed in l/min (E = 1.11 +/- 0.25; UN = 1.02 +/- 0.19); VO2max expressed in ml/min/kg (E = 40.23 +/- 6.98; UN = 40.53 +/- 6.32), VEmax (E = 40.61 +/- 8.79; UN = 38.25 +/- 8.95), R (E = 1.13 +/- 0.07; UN = 1.13 +/- 0.05), HRmax (E = 195.33 +/- 9.13; UN = 193.85 +/- 11.18), previous % HRmax (E = 92.87 +/- 4.33; UN = 92.80 +/- 4.87), and maximum watts (E = 90.00 +/- 20.56; UN = 91.25 +/- 11.33). Analysis of the results obtained in test of submaximal effort, reflected by the intensity of effort in the anaerobic threshold (AT), showed differences between the groups in the following variables: VO2max expressed in l/min. (E = 0.77 +/- 0.14; UN = 0.62 +/- 0.13), % of VO2max (E = 70.07 +/- 7.52; UN = 61.21 +/- 9.83), HR (E = 166.58 +/- 14.25; UN = 146.33 +/- 17.40), % HRmax (E = 85.31 +/-6.41; UN = 75.50 +/- 7.73), VE (E = 24.18 +/- 5.81; UN = 17.69 +/- 4.30), % VEmax (E = 59.64 +/- 8.45; UN = 46.95 +/- 10.59). No differences were found for VO2max, expressed in l/min/kg (E = 28.06 +/- 4.87; UN = 24.81 +/- 5.31) and watts (E = 51.25 +/- 17.47; UN = 45.00 +/- 9.77). CONCLUSION: The reestablishment of the ratio weight/height in early undernourished girls is also useful to indicate lack of limitation of functional capability to perform physical exercises.