title: Cycling Exercise Training Alleviates Hypoxia-Impaired Erythrocyte Rheology.
abstract: OBJECTIVE
  Physical exercise or hypoxic exposure influences hemorheology and acid-base homeostasis. Band 3 protein in erythrocytes modulates cells' rheological properties and anion transport ability. This study investigated how cycling aerobic interval training (AIT) and moderate continuous training (MCT) affect the rheological function and band 3 activity of erythrocytes under hypoxic exercise (HE) stress.
  
  
  METHODS
  Forty-five healthy sedentary men were randomized to engage in either AIT (3-min intervals at 40% and 80% of VO2max, n = 15) or MCT (sustained 60% of VO2max, n = 15) on a bicycle ergometer for 30 min · d(-1) (5 d · wk(-1) for 5 wk) or to a control group that did not perform any exercise (n = 15). Erythrocyte rheological responses to HE (100 W under 12% O2 for 30 min) were determined before and after various regimens.
  
  
  RESULTS
  Acute HE increased the aggregation and osmotic fragility of erythrocytes, decreased the deformability of erythrocytes, and depressed erythrocyte band 3 activity, as indicated by lowered anion transport ability. Following 5 wk of intervention, the AIT group exhibited maximal work rate and VO2max higher than those in the MCT and control groups. Moreover, cycling AIT and MCT diminished the extent of erythrocytes' enhanced aggregation and osmotic fragility and reduced their deformability and band 3 activity caused by HE. Additionally, erythrocyte band 3 activity was directly related to erythrocyte deformability and inversely related to erythrocyte aggregation and osmotic fragility.
  
  
  CONCLUSIONS
  Cycling AIT is superior to cycling MCT in enhancing aerobic capacity. Moreover, either cycling AIT or MCT effectively alleviates HE-evoked impairments of erythrocyte rheological characteristics and band 3 function.
authors.affiliation: 1Heart Failure Center, Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Keelung, TAIWAN; and 2Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Medical College, Chang Gung University, Tao-Yuan, TAIWAN.
authors.forename: Szu-Ling
authors.initials: SL
authors.lastname: Chou
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Huang
authors.forename: Tieh-Cheng
authors.initials: TC
authors.lastname: Fu
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Hsu
authors.forename: Jong-Shyan
authors.initials: JS
authors.lastname: Wang
mesh_terms: D000136:Acid-Base Equilibrium; D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism; D001642:Bicycling / Q000502:physiology*; D004903:Erythrocyte Aggregation; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000378:metabolism / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology; D018056:Hemorheology; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D009996:Osmotic Fragility; D010101:Oxygen Consumption; D010806:Physical Education and Training / Q000379:methods*; D017701:Reticulocyte Count; D055815:Young Adult
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte