title: Run training versus cross-training: effect of increased training on circulating leukocyte subsets.
abstract: The purpose of this study was to determine the effects of increased training via cross-training (run + cycle) and run training on circulating leukocyte subsets. Male runners (N = 11) participated in two randomly assigned increased training (IT) periods after 30 d of normal training (NT). Each IT began after a 14 d period of reduced training (80% of NT) followed by 10 d of IT (200% of NT). During IT, the subjects ran in the afternoon for 10 d (100% NT) and performed 8 additional training sessions in the morning (100% NT) on a treadmill (ITRT) or a bicycle ergometer (ITCT). Blood samples were obtained before (D0), on day 5(D5) and after 10 d (D11) of ITRT and ITCT. A significant increase in the CD4+/CD8+ ratio occurred at D5 compared with D0 and D11. The CD4+/CD8+ ratio was significantly lower during ITRT compared with ITCT at D11. The number of circulating CD3+, CD4+, and CD8+ cells were significantly reduced at D11 compared with D0. In conclusion, 10 d of IT resulted in a significant reduction in the number of circulating T cells independent of the training mode and a reduction in the CD4+/CD8+ ratio for ITRT but not for ITCT.
authors.affiliation: Department of Health Promotion and Human Performance, University of Toledo, OH 43606, USA.
authors.forename: F X
authors.initials: FX
authors.lastname: Pizza
authors.forename: M G
authors.initials: MG
authors.lastname: Flynn
authors.forename: T
authors.initials: T
authors.lastname: Sawyer
authors.forename: P G
authors.initials: PG
authors.lastname: Brolinson
authors.forename: R D
authors.initials: RD
authors.lastname: Starling
authors.forename: F F
authors.initials: FF
authors.lastname: Andres
mesh_terms: D000328:Adult; D001642:Bicycling / Q000193:education / Q000502:physiology*; D018791:CD4 Lymphocyte Count; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D003402:Creatine Kinase / Q000097:blood; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology; D018655:Lymphocyte Count; D008297:Male; D010806:Physical Education and Training; D012420:Running / Q000193:education / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000166:cytology*; D013601:T-Lymphocytes / Q000166:cytology
chemical_list: D003402:Creatine Kinase