caa a22 4500 467941637 CHVBK 20180406153014.0 cr unu---uuuuu 170328e20060501xx s 000 0 eng 10.1007/s00421-006-0152-6 doi (NATIONALLICENCE)springer-10.1007/s00421-006-0152-6 Environmental heat stress, hyperammonemia and nucleotide metabolism during intermittent exercise [Elektronische Daten] [Magni Mohr, Peter Rasmussen, Barry Drust, Bodil Nielsen, Lars Nybo] This study investigated the influence of environmental heat stress on ammonia (NH3) accumulation in relation to nucleotide metabolism and fatigue during intermittent exercise. Eight males performed 40min of intermittent exercise (15s at 306±22W alternating with 15s of unloaded cycling) followed by five 15s all-out sprints. Control trials were conducted in a 20°C environment while heat stress trials were performed at an ambient temperature of 40°C. Muscle biopsies and venous blood samples were obtained at rest, after 40min of exercise and following the maximal sprints. Following exercise with heat stress, the core and muscle temperatures peaked at 39.5±0.2 and 40.2±0.2°C to be ~ 1°C higher (P<0.05) than the corresponding control values. Mean power output during the five maximal sprints was reduced from 618±12W in control to 558±14W during the heat stress trial (P<0.05). During the hot trial, plasma NH3 increased from 31±2μM at rest to 93±6 at 40min and 151±15μM after the maximal sprints to be 34% higher than control (P<0.05). In contrast, plasma K+ and muscle H+ accumulation were lower (P<0.05) following the maximal sprints with heat stress compared to control, while muscle glycogen, CP, ATP and IMP levels were similar across trials. In conclusion, altered levels of "classical peripheral fatiguing agents” does apparently not explain the reduced capacity for performing repeated sprints following intermittent exercise in the heat, whereas the augmented systemic NH3 response may be a factor influencing fatigue during exercise with superimposed heat stress. Springer-Verlag, 2006 Sprint performance nationallicence Fatigue nationallicence Muscle metabolism nationallicence Exercise nationallicence Hyperthermia nationallicence Mohr Magni Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut Rasmussen Peter Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut Drust Barry Research Institute for Sport and Exercise Sciences, John Moore University, Liverpool, England aut Nielsen Bodil Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut Nybo Lars Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut European Journal of Applied Physiology Springer-Verlag 97/1(2006-05-01), 89-95 1439-6319 97:1<89 2006 97 421 https://doi.org/10.1007/s00421-006-0152-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-006-0152-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mohr Magni Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut NATIONALLICENCE 700 1- Rasmussen Peter Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut NATIONALLICENCE 700 1- Drust Barry Research Institute for Sport and Exercise Sciences, John Moore University, Liverpool, England aut NATIONALLICENCE 700 1- Nielsen Bodil Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut NATIONALLICENCE 700 1- Nybo Lars Institute of Exercise and Sport Sciences, Department of Human Physiology, August Krogh Institute, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen Ø, Denmark aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 97/1(2006-05-01), 89-95 1439-6319 97:1<89 2006 97 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer