title: Exercise-induced muscle damage: effect on circulating leukocyte and lymphocyte subsets.
abstract: The purpose of this study was to determine the effect of downhill and level running on circulating leukocyte and lymphocyte subsets and T lymphocyte activation. Using a random cross-over design, 10 runners completed two trials of 60 min of level running (0% grade; LR) and downhill running (-10% grade; DHR) at 70% of level VO2max. Blood samples were obtained preexercise and immediately postexercise (POST) and at 1.5, 12, 24, and 48 h of recovery. Creatine kinase activity peaked at 12 h of recovery from DHR and was not significantly altered following LR. The number of total T, CD16+, CD3+CD56+ cells were significantly higher POST DHR compared with LR. Leukocyte and neutrophil counts were significantly higher at 1.5 and 12 h of recovery from DHR compared with LR. The number of activated CD8+ cells (CD25+ CD8+) was significantly higher at 12 h of DHR compared to LR. Total T cells were significantly reduced at various time points during the 48 h of recovery from LR and DHR. In summary, DHR relative to LR resulted in a greater mobilization of lymphocytes (post), neutrophils (1.5-12 h of recovery) and activation of CD8+ cells at 12 h of recovery. In addition, reductions in circulating T lymphocyte subsets occurred following both conditions.
authors.affiliation: Department of Physical Education, Texas Christian University, Fort Worth 76129, USA.
authors.forename: F X
authors.initials: FX
authors.lastname: Pizza
authors.forename: J B
authors.initials: JB
authors.lastname: Mitchell
authors.forename: B H
authors.initials: BH
authors.lastname: Davis
authors.forename: R D
authors.initials: RD
authors.lastname: Starling
authors.forename: R W
authors.initials: RW
authors.lastname: Holtz
authors.forename: N
authors.initials: N
authors.lastname: Bigelow
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology; D003402:Creatine Kinase / Q000097:blood; D018592:Cross-Over Studies; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000473:pathology; D007958:Leukocyte Count; D007962:Leukocytes / Q000473:pathology*; D008213:Lymphocyte Activation / Q000502:physiology; D018655:Lymphocyte Count; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D009504:Neutrophils / Q000473:pathology; D012420:Running / Q000145:classification / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology*; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology
chemical_list: D003402:Creatine Kinase