caa a22 4500 467940657 CHVBK 20180406153011.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00421-005-0052-1 doi (NATIONALLICENCE)springer-10.1007/s00421-005-0052-1 The heart rate increase at the onset of high-work intensity exercise is accelerated by central blood volume loading [Elektronische Daten] [Tadayoshi Miyamoto, Yoshitake Oshima, Komei Ikuta, Hiroshi Kinoshita] Using a water immersion (WI) method, the combined effect of central blood volume (CBV) loading and work intensity on the time course of heart rate (HR) at the onset of upright dynamic exercise was investigated. Seven males cranked a cycle ergometer for 12min using their un-immersed arms at low-, moderate- and high-work intensities, followed by a 12-min rest. For WI, the pre-exercise resting cardiac output increased by 36%, while HR decreased by 22% [from 76.8 (10.4) to 59.6 (9.8) beats/min]. WI also increased the high-frequency (HF, 0.15-0.40Hz) component of the HR variability, suggesting an increased vagal activity. During the initial 2min of the exercise period at low-work intensity, HR increased by 34.9 and 25.8% in the WI and control conditions, respectively. These were 117 and 73% at high-work intensity, indicating more accelerated HR with WI than the control. The plasma norepinephrine concentration increased less during high-work intensity exercise during WI, as compared to exercise during control conditions. In conclusion, the HR increase at the onset of high-work intensity exercise is accelerated by CBV loading but not at low intensity, possibly reflecting vago-sympathetic interaction and reduced baroreflex sensitivity. Springer-Verlag, 2005 Water immersion nationallicence Central hyperbolemia nationallicence Heart rate variability nationallicence Norepinephrine nationallicence Vago-sympathetic interaction nationallicence Miyamoto Tadayoshi Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, 565-8565, Osaka, Japan aut Oshima Yoshitake Omron Institute of Life Science Co., Ltd, Kyoto, Tapan aut Ikuta Komei School of Health and Sport Sciences, Osaka University, Osaka, Japan aut Kinoshita Hiroshi School of Health and Sport Sciences, Osaka University, Osaka, Japan aut European Journal of Applied Physiology Springer-Verlag 96/1(2006-01-01), 86-96 1439-6319 96:1<86 2006 96 421 https://doi.org/10.1007/s00421-005-0052-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-005-0052-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Miyamoto Tadayoshi Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, 565-8565, Osaka, Japan aut NATIONALLICENCE 700 1- Oshima Yoshitake Omron Institute of Life Science Co., Ltd, Kyoto, Tapan aut NATIONALLICENCE 700 1- Ikuta Komei School of Health and Sport Sciences, Osaka University, Osaka, Japan aut NATIONALLICENCE 700 1- Kinoshita Hiroshi School of Health and Sport Sciences, Osaka University, Osaka, Japan aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 96/1(2006-01-01), 86-96 1439-6319 96:1<86 2006 96 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer