Browsing by Autor "D. Desplanches"

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Endurance Training at High Altitude: Effects of Inhalation of a Normoxic Gas Mixture during Exercise
(Portland Press, 1994) R. Favier; Hilde Spielvogel; D. Desplanches; Guido Ferretti; Bengt Kayser; Stan L. Lindstedt; Hans Hoppeler
Conference Abstract| January 01 1994 Endurance Training at High Altitude: Effects of Inhalation of a Normoxic Gas Mixture during Exercise R Favier; R Favier 1 Instituto Boliviano de Biologia de Altura-La Paz-Bolivia Search for other works by this author on: This Site PubMed Google Scholar H Spielvogel; H Spielvogel 1 Instituto Boliviano de Biologia de Altura-La Paz-Bolivia Search for other works by this author on: This Site PubMed Google Scholar D Desplanches; D Desplanches 2 Laboratoire de Physiologie, Université Claude Bernard-Lyon-France Search for other works by this author on: This Site PubMed Google Scholar G Ferretti; G Ferretti 3 Laboratoire de Physiologie, Centre médical Universitaire-Genève-Switzerland Search for other works by this author on: This Site PubMed Google Scholar B Kayser; B Kayser 3 Laboratoire de Physiologie, Centre médical Universitaire-Genève-Switzerland Search for other works by this author on: This Site PubMed Google Scholar S Lindstedt; S Lindstedt 4 Biology Department, Northern Arizona University-Flagstaff-USA Search for other works by this author on: This Site PubMed Google Scholar H Hoppeler H Hoppeler 5 Anatomisches Institut, Universität Bern-Bern-Switzerland Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1994) 87 (s1): 17–18. https://doi.org/10.1042/cs087s017a Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation R Favier, H Spielvogel, D Desplanches, G Ferretti, B Kayser, S Lindstedt, H Hoppeler; Endurance Training at High Altitude: Effects of Inhalation of a Normoxic Gas Mixture during Exercise. Clin Sci (Lond) 1 January 1994; 87 (s1): 17–18. doi: https://doi.org/10.1042/cs087s017a Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1994 The Biochemical Society and the Medical Research Society1994 Article PDF first page preview Close Modal You do not currently have access to this content.
Exercise training in chronic hypoxia has no effect on ventilatory muscle function in humans
(Elsevier BV, 1998) R. Thomas; Paul C. LaStayo; Hans Hoppeler; R. Favier; Guido Ferretti; Bengt Kayser; D. Desplanches; Hilde Spielvogel; Stan L. Lindstedt
Funktionelle und strukturelle Anpassungen an ein Dauerleistungstraining ober- oder unterhalb der 4 mM/l-Laktatschwelle
(1997) M. Leuenberger; Andi Grünenfelder; Hans Hoppeler; R. Favier; D. Desplanches; Hilde Spielvogel; Stan L. Lindstedt; Guido Ferretti; Bengt Kayser
Hormonal and metabolic adjustments during exercise in hypoxia or normoxia in highland natives
(American Physiological Society, 1996) R. Favier; D. Desplanches; Hans Hoppeler; Esperanza Cáceres; A. Grünenfelder; H. Koubi; M. Leuenberger; B. Semporé; L. Tüscher; Hilde Spielvogel
In sea-level natives, exposure to hypoxia for a few weeks is characterized by an increased dependence on blood glucose and a decreased reliance on lactate for energy metabolism during exercise. These metabolic adjustments have been attributed to behavioral changes in the sympathoadrenergic and pancreatic systems. The aim of this study was to test the hypothesis of a reduced sympathoadrenergic activation and subsequent metabolic changes when high-altitude natives are acutely exposed to normoxia. Young Andean natives performed incremental exercise to exhaustion during hypoxia (arterial PO2 55.1 +/- 1.1 Torr) or during acute normoxia (arterial PO2 78.7 +/- 1.7 Torr). As a whole, oxygen uptake was increased in normoxia compared with hypoxia during graded exercise. This finding is not related to a decrease in anaerobic metabolism but rather is interpreted as a consequence of a shift in substrate utilization during exercise (increased contribution of fat as assessed by a reduction in the respiratory exchange ratio). These metabolic changes are not accompanied by modifications of glucoregulatory hormones (catecholamines, insulin, and glucagon). In particular, the exercise-induced catecholamine secretion was similar in chronic hypoxia and acute normoxia. As a consequence, blood lactate accumulation during incremental exercise was similar in both conditions. It is concluded that high-altitude natives do not display any sign of a greater sympathoadrenergic activation during chronic hypoxia and that the exercise-induced hormonal changes remained unaffected by acute inhalation of a normoxic gas mixture.
Lactate and epinephrine during exercise in altitude natives
(American Physiological Society, 1996) Bengt Kayser; R. Favier; Guido Ferretti; D. Desplanches; Hilde Spielvogel; H. Koubi; B. Semporé; Hans Hoppeler
We tested the hypothesis that the reported low blood lactate accumulation ([La]) during exercise in altitude-native humans is refractory to hypoxianormoxia transitions by investigating whether acute changes in inspired O2 fraction (FIo2) affect the [La] vs. power output (W) relationship or, alternatively, as reported for lowlanders, whether changes in [La] vs. W on changes in FIo2 are related to changes in blood epinephrine concentration ([Epi]). Altitude natives [n = 8, age 24 +/- 1 (SE) yr, body mass 62 +/- 3 kg, height 167 +/- 2 cm] in La Paz, Bolivia (3,600 m) performed incremental exercise with two legs and one leg in chronic hypoxia and acute normoxia (AN). Submaximal one- and two-leg O2 uptake (Vo2) vs. W relationships were not altered by FIo2. AN increased two-leg peak Vo2 by 10% and peak W by 7%. AN paradoxically decreased one-leg peak Vo2 by 7%, whereas peak W remained the same. The [La] vs. W relationships were similar to those reported in unacclimatized lowlanders. There was a shift to the right on AN, and maximum [La] was reduced by 7 and 8% for one- and two-leg exercises, respectively. [Epi] and [La] were tightly related (mean r = 0.81) independently of FIo2. Thus normoxia attenuated the increment in both [La] and [Epi] as a function of W, whereas the correlation between [La] and [Epi] was unaffected. These data suggest loose linkage of glycolysis to oxidative phosphorylation under influence from [Epi]. In conclusion, high-altitude natives appear to be not fundamentally different from lowlanders with regard to the effect of acute changes in FIo2 on [La] during exercise.
Maximal exercise performance in chronic hypoxia and acute normoxia in high-altitude natives
(American Physiological Society, 1995) R. Favier; Hilde Spielvogel; D. Desplanches; G. Ferretti; Bengt Kayser; Hans Hoppeler
Maximal O2 uptake (VO2max) was determined on a bicycle ergometer in chronic hypoxia (CH) and during acute exposure to normoxia (AN) in 50 healthy young men who were born and had lived at 3,600 m altitude (La Paz, Bolivia). VO2max was significantly improved (approximately 8%) by AN. However, the difference in VO2max measured in CH and AN (delta VO2max) was lower than that reported in sea-level natives (SN) who exercised in chronic normoxia and acute hypoxia. It is shown that high-altitude natives (HN) and SN have a similar VO2max in normoxia, but highlanders can attain a greater VO2max when O2 availability is reduced by altitude exposure. In addition, in HN, the higher the subject's VO2max in hypoxia, the smaller his delta VO2max. These results contrast with the data obtained in 14 lowlanders acclimatized to high altitude who showed that their delta VO2max was positively related to their VO2max in hypoxia, as previously reported in SN who exercised in acute hypoxia (A. J. Young, A. Cymerman, and R. L. Burse. Eur. J. Appl. Physiol. Occup. Physiol. 54: 12-15, 1985). Furthermore, arterial O2 saturation of HN behaved differently from acclimatized lowland natives, inasmuch as it fell less during exercise both in CH and AN. HN with high aerobic capacity display a lower exercise ventilation and a reduced arterial saturation, which could explain their inability to improve VO2max with normoxia.(ABSTRACT TRUNCATED AT 250 WORDS)
Maximal Exercise Performance in Chronic Hypoxia and Acute Normoxia in High-Altitude Natives
(Portland Press, 1994) R. Favier; Hilde Spielvogel; D. Desplanches; Guido Ferretti; Bengt Kayser; Stan L. Lindstedt; Hans Hoppeler
Conference Abstract| January 01 1994 Maximal Exercise Performance in Chronic Hypoxia and Acute Normoxia in High-Altitude Natives R Favier; R Favier 1 Instituto Boliviano de Biologia de Altura-La Paz-Bolivia Search for other works by this author on: This Site PubMed Google Scholar H Spielvogel; H Spielvogel 1 Instituto Boliviano de Biologia de Altura-La Paz-Bolivia Search for other works by this author on: This Site PubMed Google Scholar D Desplanches; D Desplanches 2 Laboratoire de Physiologie, Université Claude Bernard-Lyon-France Search for other works by this author on: This Site PubMed Google Scholar G Ferretti; G Ferretti 3 Laboratoire de Physiologie, Centre médical Universitaire-Genève-Switzerland Search for other works by this author on: This Site PubMed Google Scholar B Kayser; B Kayser 3 Laboratoire de Physiologie, Centre médical Universitaire-Genève-Switzerland Search for other works by this author on: This Site PubMed Google Scholar S Lindstedt; S Lindstedt 4 Biology Department, Northern Arizona University-Flagstaff-USA Search for other works by this author on: This Site PubMed Google Scholar H Hoppeler H Hoppeler 5 Anatomisches Institut, Universität Bern-Bern-Switzerland Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1994) 87 (s1): 46–47. https://doi.org/10.1042/cs087s046a Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation R Favier, H Spielvogel, D Desplanches, G Ferretti, B Kayser, S Lindstedt, H Hoppeler; Maximal Exercise Performance in Chronic Hypoxia and Acute Normoxia in High-Altitude Natives. Clin Sci (Lond) 1 January 1994; 87 (s1): 46–47. doi: https://doi.org/10.1042/cs087s046a Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1994 The Biochemical Society and the Medical Research Society1994 Article PDF first page preview Close Modal You do not currently have access to this content.
Muscle tissue adaptations of high-altitude natives to training in chronic hypoxia or acute normoxia
(American Physiological Society, 1996) D. Desplanches; Hans Hoppeler; L. Tüscher; M. H. Mayet; Hilde Spielvogel; G. Ferretti; Bengt Kayser; M. Leuenberger; A. Grünenfelder; R. Favier
Twenty healthy high-altitude natives, residents of La Paz, Bolivia (3,600 m), participated in 6 wk of endurance exercise training on bicycle ergometers, 5 times/wk, 30 min/session, as previously described in normoxia-trained sea-level natives (H. Hoppeler, H. Howald, K. E. Conley, S. L. Lindstedt, H. Claassen, P. Vock, and E. R. Weibel. J. Appl. Physiol. 59: 320-327, 1985). A first group of 10 subjects was trained in chronic hypoxia (HT; barometric pressure = 500 mmHg; inspired O2 fraction = 0.209); a second group of 10 subjects was trained in acute normoxia (NT; barometric pressure = 500 mmHg; inspired O2 fraction = 0.314). The workloads were adjusted to approximately 70% of peak O2 consumption (VO2peak) measured either in hypoxia for the HT group or in normoxia for the NT group. VO2peak determination and biopsies of the vastus lateralis muscle were taken before and after the training program. VO2peak in the HT group was increased (14%) in a way similar to that in NT sea-level natives with the same protocol. Moreover, VO2peak in the NT group was not further increased by additional O2 delivery during the training session. HT or NT induced similar increases in muscle capillary-to-fiber ratio (26%) and capillary density (19%) as well as in the volume density of total mitochondria and citrate synthase activity (45%). It is concluded that high-altitude natives have a reduced capillarity and muscle tissue oxidative capacity; however, their training response is similar to that of sea-level residents, independent of whether training is carried out in hypobaric hypoxia or hypobaric normoxia.
Training in hypoxia vs. training in normoxia in high-altitude natives
(American Physiological Society, 1995) R. Favier; Hilde Spielvogel; D. Desplanches; G. Ferretti; Bengt Kayser; A. Grünenfelder; M. Leuenberger; L. Tüscher; Esperanza Cáceres; Hans Hoppeler
To determine the interactions between endurance training and hypoxia on maximal exercise performance, we performed a study on sedentary high-altitude natives who were trained in normoxia at the same relative (n = 10) or at the same absolute (n = 10) intensity of work as hypoxia-trained subjects (n = 10). The training-induced improvement of maximal oxygen uptake (VO2max) in hypoxia-trained subjects was similar to that obtained in normoxia-trained sea-level natives submitted to the same training protocol (H. Hoppeler, H. Howald, K. Conley, S. L. Lindstedt, H. Claassen, P. Vock, and E. W. Weibel. J. Appl. Physiol. 59: 320-327, 1985). Training at the same absolute work intensity in the presence of increased oxygen delivery failed to provide a further increase in VO2max. VO2max was not improved to a greater extent by simultaneously increasing absolute work intensity and O2 delivery during the training sessions. In addition, training in normoxia is accompanied by an increased blood lactate accumulation during maximal exercise, leading to greater drops in arterial pH, bicarbonate concentration, and base excess. We conclude that, in high-altitude natives, 1) training at altitude does not provide any advantage over training at sea level for maximal aerobic capacity, whether assessed in chronic hypoxia or in acute normoxia; 2) VO2max improvement with training cannot be further enhanced by increasing O2 availability alone or in combination with an increased work intensity during the exercising sessions; and 3) training in normoxia in these subjects results in a reduced buffer capacity.