Summary
A group of 10 prepubertal boys was studied during prolonged exercise (60 min) on bicycle ergometer and on treadmill at two levels of work load (appr. 40% and 60% \(\dot V\)O2 max). The hematocrit, serum proteins, Cl− and K+ were followed, and from the blood hematocrit changes the plasma volume changes were calculated. At the exercises of lower intensity of both types a slight hemodilution was found (appr. +5% increase in plasma volume), at higher intensity practically no changes could be demonstrated. These findings are supported by the values of serum protein concentration, where no increase was found, and by the fact that at the lower work loads a rather decreasing trend was found for this blood constituent. These findings are at variance with those in adults under similar conditions. The authors suggest that different changes of plasma volume during exercise in boys than in adults could be related to the disparate lactate production and fate in these age groups.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ahlborg, B., Bergström, J., Ekelund, J. G., Hultman, E.: Muscle glycogen and muscle electrolytes during prolonged physical exercise. Acta physiol. scand. 70, 129–142 (1967)
Astrand, P. O.: Experimental studies of physical working capacity in relation to sex and age. Copenhagen: Munksgaard 1952
van Beaumont, W., Greenleaf, J. E., Juhos, L.: Disproportional changes in hematocrit, plasma volume changes and proteins during exercise and bed rest. J. appl. Physiol. 33, 55–62 (1972)
van Beaumont, W., Strand, J. C., Petrofsky, J. S., Hipskind, S. G., Greenleaf, J. E.: Changes in total plasma content of electrolytes and proteins with maximal exercise. J. appl. Physiol. 34, 102–106 (1973)
Bergström, J., Guarneri, G., Hultman, E.: Carbohydrate metabolism and electrolyte changes in human muscle tissue during heavy exercise. J. appl. Physiol. 30, 122–125 (1971)
Ekblom B., Astrand, P. O., Saltin, B., Stenberg, J., Wallström, B.: Effect of training on circulatory response to exercise. J. appl. Physiol. 24, 518–528 (1968)
Ekelund, L. G.: Circulatory and respiratory adaptation during prolonged exercise of moderate intensity in the sitting position. Acta physiol. scand. 69, 327–340 (1967)
Eriksson, B. O., Karlsson, J., Saltin, B.: Muscle metabolites during exercise in pubertal boys. Acta paediat, scand., Suppl. 217, 154–157 (1971)
Jacobsson, S., Kjellmer, J.: Accumulation of fluid in exercising skeletal muscle. Acta physiol. scand. 60, 286–292 (1964)
Máček, M., Vávra, J.: Cardiopulmonary and metabolic changes during exercise in children 6–14 years old. J. appl. Physiol. 30, 202–204 (1971)
Máček, M., Vávra, J., Novosadová, J.: Prolonged exercise in prepubertal boys. I. Cardiovascular and metabolic adjustment. Europ. J. appl. Physiol. 35, 291–298 (1976)
Mellander, S.: Tissue osmolality as a mediator of exercise hyperemia. Scand. J. clin. Lab. Invest. 29, 139–144 (1972)
Poortmans, J. R.: Influence of physical exercise on proteins in biological fluids. In: Biochemistry of exercise. Medicine and sport, Vol. 3 (J. R. Poortmans, ed.), pp. 312–327. Basel: Karger 1969
Saltin, B., Stenberg, J.: Circulatory response to prolonged severe exercise. J. appl. Physiol. 19, 833–838 (1964)
Senay, L. C.: Movement of water, protein, and crystalloids between vascular and extravascular compartments in heat-exposed men during dehydration and following limited relief of dehydration. J. Physiol. (Lond.) 210, 617–635 (1970)
Trtílek, J.: Difenylkarbazon jako merkurimetrický indikátor stanovení chloridů v moči a krvi. Bratisl. lek. Listy 17, 266–273 (1973)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Máček, M., Vávra, J. & Novosadová, J. Prolonged exercise in prepubertal boys. Europ. J. Appl. Physiol. 35, 299–303 (1976). https://doi.org/10.1007/BF00423290
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00423290