title: Effects of submaximal exercise on blood rheology and sympathetic nerve activity.
abstract: BACKGROUND
  To explore the acute effects of submaximal exercise on blood rheology and sympathetic nerve activity.
  
  
  RESULTS
  The effects of exercise (20 or 80 Watts (W)) on blood rheology and sympathetic nerve activity were assessed in 10 healthy Japanese men. Blood sampling and heart rate variability (HRV) recording were performed during 20-min supine rest and standing ergometric exercise (20 W for 10 min, 80 W for 10 min) and recovery. Blood passage time across the microchannels (diameter, 7 microm) as a parameter of blood rheology, and the number of adhesive leukocytes on microchannel terraces as a parameter of leukocyte activation were measured. Sympathetic nerve activity was evaluated by plasma noradrenalin levels and the ratio of low-frequency (LF)/high-frequency (HF) by spectral analysis of HRV. Compared with values while supine at rest, significant increases in hematocrit, leukocyte count, noradrenalin level and blood passage time were seen after strenuous ergometer exercise at 80 W (P<0.01 each). The LF/HF ratio and nitric oxide metabolites tended to be increased with 80 W exercise.
  
  
  CONCLUSIONS
  Strenuous exercise dynamically alters blood rheological parameters, probably by changes in hematocrit and sympathetic nerve activity.
authors.affiliation: First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
authors.forename: Nahoko
authors.initials: N
authors.lastname: Ikeda
authors.forename: Takanori
authors.initials: T
authors.lastname: Yasu
authors.forename: Ken
authors.initials: K
authors.lastname: Tsuboi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sugawara
authors.forename: Norifumi
authors.initials: N
authors.lastname: Kubo
authors.forename: Tomio
authors.initials: T
authors.lastname: Umemoto
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Arao
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kawakami
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Momomura
mesh_terms: D000328:Adult; D001775:Blood Circulation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006400:Hematocrit; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D009638:Norepinephrine / Q000097:blood; D010953:Plasma Volume / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D012212:Rheology; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D009569:Nitric Oxide; D009638:Norepinephrine