title: Hematological recovery in male ultramarathon runners: the effect of variations in training load and running time.
abstract: OBJECTIVE
  Haematological response to the 2001 downhill Comrades Marathon was compared in high (>120 km/w in training; 3 weeks of pre-race taper) and low (<80 km/w in training; 2 weeks of pre-race taper) training status groups.
  
  
  METHODS
  Full blood counts, differential lymphocyte counts (CD3, CD4, CD8, CD19, CD56), serum cortisol, C-reactive protein (CRP) and creatine kinase (CK) were measured in blood samples donated 21 hours before and 16 hours after a 90 km ultramarathon.
  
  
  RESULTS
  Despite significantly faster mean race finishing time (8.03 h vs 10.53 h; p<0.001) and greater percentage incidence (55.6% vs 40%) of post-race upper respiratory tract infection (URTI) in the highly trained group, these faster runners did not show evidence of a slower post-race recovery in terms of total leukocyte, neutrophil, total or differential lymphocyte counts (p>0.05). CRP concentrations were, however, markedly higher in the slower, less trained group (65.3+/-10.7 vs 38.3+/-5.9; p<0.01).
  
  
  CONCLUSIONS
  Despite greater systemic evidence of post-race muscle inflammation and an acute phase response in the slower runners in a downhill ultramarathon race, the haematological recovery of well trained runners who undergo a 3-week taper period prior to the ultramarathon is not different to that in less trained runners who spend almost 3 hours longer on the road. The higher prevalence of post-race URTI symptoms in the fast, well trained group does not appear to be related to lymphocyte recovery in peripheral blood.
authors.affiliation: Department of Physiology, School of Medical Sciences, Faculty of Medicine, University of Natal, Durban, South Africa. futree@nu.ac.za
authors.forename: E M
authors.initials: EM
authors.lastname: Peters
authors.forename: P J
authors.initials: PJ
authors.lastname: Robson
authors.forename: N C
authors.initials: NC
authors.lastname: Kleinveldt
authors.forename: V L
authors.initials: VL
authors.lastname: Naicker
authors.forename: V D
authors.initials: VD
authors.lastname: Jogessar
mesh_terms: D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D010806:Physical Education and Training / Q000379:methods*; D020127:Recovery of Function / Q000502:physiology*; D012420:Running / Q000502:physiology*
chemical_list: D002097:C-Reactive Protein