Muscle Metabolism in Children—a Review

Eriksson, Bengt O.

doi:10.1111/j.1651-2227.1980.tb15304.x

Cited by 78 publications

(43 citation statements)

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“…The largest differences in THR between adults and children occurred after high-intensity exercise, and it is in the above-AT range where increases in hydrogen ion, lactate, and catecholamines are known to be smaller in children compared with adults (22)(23)(24). Thus, we hypothesize that the differences in HR response to work intensity are a reflection of substantially different hormonal and metabolic responses to high-intensity exercise in adults compared with children.…”

Section: Discussionmentioning

confidence: 99%

Heart Rate Recovery from 1 Minute of Exercise in Children and Adults

1991

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ABSTRACT. Previous studies demonstrated that the time required for oxygen uptake, COz production, and minute ventilation to return to baseline levels after I-min bursts of exercise is different in children compared with adults. To test the hypothesis that the heart rate (HR) recovery time after exercise is also different in children compared with adults, we examined H R in 10 children (range 7-11 y old) and 12 adults (26-42 y old) for 10 min after I min of cycle ergometer exercise. Each subject exercised a t work rates corresponding to 80% of the lactate or anaerobic threshold (AT), 50% of the difference between AT and maximal O 2 uptake (A), 100% of maximal uptake, and 125% of maximal uptake. Gas exchange was measured breath by breath. In adults, the H R recovery time increased significantly with work intensity a s judged by the time constant of a single exponential curve fit to postburstexercise H R 123 f 8 (SD) s a t 80% AT, 55 f 16 at 50%A, 7 4 f 13 a t 100% of maximal uptake, and 83 k 20 a t 125% of maximal uptake]. H R recovery time tended to increase with work intensity in children (16 f 7, 20 f 4, 23 f 7, and 27 f 9; for 80%AT, 50%A, 100% of maximal uptake, and 125% of maximal uptake respectively), but to a much smaller extent, and the H R recovery time was significantly smaller in children in the high-intensity (above AT) range of exercise (p < 0.001). Despite the markedly faster recoveries in children, the time course of the O 2 pulse (Voz/ HR) was indistinguishable between children and adults. These data suggest that the regulation of H R after highintensity exercise is different in children compared with adults, and that the pulsatile delivery of O z to the tissues is controlled during the growth period. (Pediatr Res 29: 575-579,1991) Abbreviations AT, anaerobic threshold HR, heart rate ~0 2 , 0 2 uptake vcoz, C 0 2 production v*:, minute ventilation vozmax, maximal O 2 uptake %max, % of Vo-m a x A, difference between vo2max and AT THR, H R recovery timeThe adaptive response to sudden changes in metabolic rate can be characterized by physiologic responses at the beginning of exercise as well as by those occurring in the recovery phase. Sudden changes in metabolic rate are common occurrences in children who, in general, tend toward frequent short intervals of physical activity. In previous studies of gas exchange responses to exercise, we observed that growth-related changes of V O~ kinetics (i.e. the time course of VO? adjustments at the onset of exercise) were the same in adults and children, but dynamic ventilatory (VI-) and Vco7 responses were faster in children ( I , 2). Similarly, in recent preliminary studies (3, 4), the recovery period (i.e. the time required to return to baseline values after 1 min of exercise) for Vo2 was surprisingly similar in adults and children over a,wide range of exercise intensities, whereas recovery for V E and VcoZ was substantially faster in children compared with adults for exercise performed in the high-intensity range.The goal of our study was to determine w...

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Section: Discussionmentioning

confidence: 99%

Heart Rate Recovery from 1 Minute of Exercise in Children and Adults

1991

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“…Little is known about ventilatory responses in the high-intensity range when respiration is regulated not only by Vcoz but also by increases in hydrogen ion concentration resulting from lactic acid production (6). Both of these coupled mechanisms (lactic acid production and reduction in pH) appear to be less active in children than in adults (6)(7)(8)(9). Thus, it seemed reasonable to hypothesize that the differences in ventilatory responses between children and adults would be greater in the high-intensity exercise range.…”

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confidence: 99%

Maturation of Ventilatory Responses to 1-Minute Exercise

Armon

Zanconato

1991

Pediatr Res

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ABSTRACT. To test the hypothesis that ventilatory responses to exercise mature during growth in healthy children, we examined C 0 2 production (VCO~) and minute ventilation (VE) before, during, and for 10 min after 1-min bursts of cycle ergometry exercise. Ten children (range: 7-11 y old) and 13 adults (26-42 y old) exercised at work rates corresponding to 50 and 80% of the anaerobic or lactate threshold, 50% of the difference between anaerobic threshold and maximum 0 2 consumption, 100% of maximum O2 consumption, and 125% of maximum 0 2 consumption (125% max). Gas exchange was measured breath by breath. Children recovered faster from high-intensity (above anaerobic threshold) exercise as judged by the time constant of single exponential curve-fits to postexercise Vco2 (55 f 10 s (1 SD) at 125%. max in children compared with 92 2 17 s at 125% max in adults; p < 0.0011 and VE (58 f 10 s at 125% max in children compared with 125 & 37 s in adults, p c 0:001). Although we found no significant difference between VCOZ and VE recovery times in children, VE was significantly slower than Vco2 in adults for highintensity exercise. Moreover, recovery times in adults increased with work intensity but were independent of them in children. Whereas the C 0 2 costs [calculated as total C 0 2 produced above baseline per unit work done (mL. J-I)] increased with work intensity in adults, no similar significant relationship was observed in children. Finally, at 125% max, the ratio of C 0 2 cost to O2 cost was 1.48 f 0.07, less than the ratio in adults (1.83 -C 0.07, p < 0.01).These results demonstrate marked differences in dynamic ventilatory response to short bursts of exercise reflecting maturation of both respiratory control and cellular metabolic factors. (Pediatr Res 29: 362-368, 1991) Abbreviations AT, anaerobic threshold VCOZ, C 0 2 production VE, minute ventilation VO~, 0 2 consumption Petco2, end-tidal Pco2 Vo2max, maximum O2. uptake A, difference between V02max and AT % max, % of Vo2max 7Vco2, time constant for V C O~ recovery 7VE, time constant for Ve recovery Ventilation in humans is regulated to maintain cellular homeostasis of COz and bicarbonate when the metabolic rate changes. The link between cellular activity and ventilation is, in large part, dependent on the distribution and transport of .COz molecules (l,2). There is evidence that the linkage between Vco2 and VE undergoes a process of maturation during growth, i.e. there is a difference between children and adults in the ventilatory response to changes in metabolic rate (3). The magnitude and mechanisms of these differences have not been fully elucidated, most likely because studying gas exchange in ways that are acceptable to children is difficult and because there are no uniform approaches to normalizing physiologic responses in subjects of widely different sizes. In this study, we employed an exercise protocol specifically designed for the behavioral characteristics of children, and the data were normalized and analyzed in a manner that facilitated compar...

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“…That was the first work where age changes in possible human anaerobic -glycolytic source at the tissue level were discovered. Next by means of biochemical (Eriksson, 1980;Ferretti et al, 1994;Kornienko et al, 1980;Ratel et al, 2002), histochemical (Tambovtseva, 2003;Kornienko et al, 2000) and physiological (Kornienko et al, 2000;Pyarnat & Viru, 1975;Son'kin, 1988;) methods numerous confirmations of an abrupt activation of anaerobic -glycolytic energy production in the process of pubescence reconstructions were obtained, especially for boys (Boisseau & Delamarche, 2000;Van Praagh & Dore, 2002).…”

Section: Age Changes Of Anaerobic Metabolism Ferments Activity In Musmentioning

confidence: 99%