caa a22 4500 467940509 CHVBK 20180406153011.0 cr unu---uuuuu 170328e20060901xx s 000 0 eng 10.1007/s00421-006-0252-3 doi (NATIONALLICENCE)springer-10.1007/s00421-006-0252-3 Factors determining the time course of $${\dot{V}}\hbox{O}_{2\max}$$ decay during bedrest: implications for $${\dot{V}}\hbox{O}_{2\max}$$ limitation [Elektronische Daten] [C. Capelli, G. Antonutto, M. Kenfack, M. Cautero, F. Lador, C. Moia, E. Tam, G. Ferretti] The aim of this study was to characterize the time course of maximal oxygen consumption $$({\dot{V}}\hbox{O}_{2\max})$$ changes during bedrests longer than 30days, on the hypothesis that the decrease in $${\dot{V}}\hbox{O}_{2\max}$$ tends to asymptote. On a total of 26 subjects who participated in one of three bedrest campaigns without countermeasures, lasting 14, 42 and 90days, respectively, $${\dot{V}}\hbox{O}_{2\max}$$ maximal cardiac output $$(\dot{Q}_{\rm max})$$ and maximal systemic O2 delivery $$({\dot{Q}}\hbox{aO}_{2{\rm max}})$$ were measured. After all periods of HDT, $${\dot{V}}\hbox{O}_{2\max},\;{\dot{Q}}_{\rm max}$$ and $${\dot{Q}}\hbox{aO}_{2{\rm max}}$$ were significantly lower than before. The $${\dot{V}}\hbox{O}_{2\max}$$ decreased less than $${\dot{Q}}_{\rm max}$$ after the two shortest bedrests, but its per cent decay was about 10% larger than that of $${\dot{Q}}_{\rm max}$$ after 90-day bedrest. The $${\dot{V}}\hbox{O}_{2\max}$$ decrease after 90-day bedrest was larger than after 42- and 14-day bedrests, where it was similar. The $${\dot{Q}}_{\rm max}$$ and $${\dot{Q}}\hbox{aO}_{2{\rm max}}$$ declines after 90-day bedrest was equal to those after 14- and 42-day bedrest. The average daily rates of the $${\dot{V}}\hbox{O}_{2\max}, \;{\dot{Q}}_{\rm max}$$ and $${\dot{Q}}\hbox{aO}_{2{\rm max}}$$ decay during bedrest were less if the bedrest duration were longer, with the exception of that of $${\dot{V}}\hbox{O}_{2\max}$$ in the longest bedrest. The asymptotic $${\dot{V}}\hbox{O}_{2\max}$$ decay demonstrates the possibility that humans could keep working effectively even after an extremely long time in microgravity. Two components in the $${\dot{V}}\hbox{O}_{2\max}$$ decrease were identified, which we postulate were related to cardiovascular deconditioning and to impairment of peripheral gas exchanges due to a possible muscle function deterioration. Springer-Verlag, 2006 Bedrest nationallicence Exercise nationallicence Maximal oxygen uptake limitation nationallicence Maximal cardiac output nationallicence Maximal cardiovascular oxygen transport nationallicence Capelli C. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut Antonutto G. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut Kenfack M. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut Cautero M. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut Lador F. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut Moia C. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut Tam E. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut Ferretti G. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut European Journal of Applied Physiology Springer-Verlag 98/2(2006-09-01), 152-160 1439-6319 98:2<152 2006 98 421 https://doi.org/10.1007/s00421-006-0252-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-006-0252-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Capelli C. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut NATIONALLICENCE 700 1- Antonutto G. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut NATIONALLICENCE 700 1- Kenfack M. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut NATIONALLICENCE 700 1- Cautero M. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut NATIONALLICENCE 700 1- Lador F. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut NATIONALLICENCE 700 1- Moia C. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut NATIONALLICENCE 700 1- Tam E. Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, P.le M. Kolbe 4, 33100, Udine, Italy aut NATIONALLICENCE 700 1- Ferretti G. Département de Physiologie, Centre Médical Universitaire, 1 rue Michel Servet, 1211, Genève 4, Switzerland aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 98/2(2006-09-01), 152-160 1439-6319 98:2<152 2006 98 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer