title: Effects of high- vs moderate-intensity exercise on natural killer cell activity.
abstract: The effect of 45 min of high- (80% VO2max) vs moderate- (50% VO2max) intensity treadmill exercise on natural killer cell cytotoxic activity (NKCA) was investigated in 10 well-conditioned (66.0 +/- 1.9 ml.kg-1.min-1), young males (22.1 +/- 1.3 yr). Blood samples were taken before and immediately after exercise, with three more samples taken during 3.5 h of recovery, and analyzed for proportion of NK cells (CD3-CD16+CD56+) and NKCA. Exercise at 80% vs 50% VO2max resulted in a greater immediate postexercise increase in proportion of NK cells, followed by a 1-h and 2-h decrease below preexercise levels for both intensity conditions. NKCA rose significantly above preexercise levels following high- but not moderate-intensity exercise. For both exercise intensity conditions, NKCA tended to drop below preexercise levels by 1 h postexercise, rising back to preexercise levels by 3.5 h postexercise. When NKCA was expressed on a per-NK cell basis, however, no change relative to preexercise levels occurred following moderate-intensity exercise, while a significant increase occurred after 2-h recovery from high-intensity exercise. These data demonstrate that both high- and moderate-intensity exercise are associated with significant shifts in circulating proportions of NK cells which significantly influence interpretation of NKCA data based on assays using separated mononuclear cells.
authors.affiliation: Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC 28608.
authors.forename: D C
authors.initials: DC
authors.lastname: Nieman
authors.forename: A R
authors.initials: AR
authors.lastname: Miller
authors.forename: D A
authors.initials: DA
authors.lastname: Henson
authors.forename: B J
authors.initials: BJ
authors.lastname: Warren
authors.forename: G
authors.initials: G
authors.lastname: Gusewitch
authors.forename: R L
authors.initials: RL
authors.lastname: Johnson
authors.forename: J M
authors.initials: JM
authors.lastname: Davis
authors.forename: D E
authors.initials: DE
authors.lastname: Butterworth
authors.forename: S L
authors.initials: SL
authors.lastname: Nehlsen-Cannarella
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001402:B-Lymphocytes; D002395:Catecholamines / Q000097:blood; D003602:Cytotoxicity, Immunologic / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007694:Killer Cells, Natural / Q000502:physiology*; D007958:Leukocyte Count; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010953:Plasma Volume; D013601:T-Lymphocytes; D013997:Time Factors
chemical_list: D002395:Catecholamines; D006854:Hydrocortisone