title: Combined effects of age and exercise on thromboxane B2 and platelet activation.
abstract: Nine healthy young (27.8 +/- 0.8 yr old, YM) and nine healthy older men (55.4 +/- 1.3 yr old, OM) ran on a treadmill at 70-75% of maximal O2 consumption for 30 min to determine the combined effects of age and acute exercise on plasma thromboxane B2 (TxB2) and beta-thromboglobulin (beta-TG). Blood samples (10 ml) were collected in tubes containing 0.5 ml of 4.5 mM EDTA, 30 mM acetylsalicylic acid, and 1 microM prostaglandin E1 after 15 min of rest, immediately after exercise, and at 30 min of recovery. Concentrations of TxB2 and beta-TG were determined by radioimmunoassay. Samples were adjusted for hemoconcentration and changes in platelet count not accounted for by plasma volume shifts. Data were analyzed with repeated-measures analysis of variance and Tukey's post hoc technique. Resting TxB2 was 53.3 +/- 9.6 and 79.0 +/- 18.2 pg/ml for the YM and OM, respectively. beta-TG at rest was 152.5 +/- 13.9 and 114.0 +/- 10.9 ng/ml for the YM and OM, respectively. No significant age group or exercise-induced differences for TxB2 or beta-TG were found immediately after exercise. TxB2 in the OM (101.7 +/- 16.4 pg/ml) 30 min after exercise was significantly (P = 0.05) higher than that in the YM (54.4 +/- 6.2 pg/ml). beta-TG values 30 min after exercise were not significantly different: 183.3 +/- 26.9 and 169.9 +/- 17.0 ng/ml in the OM and YM, respectively. These data suggest that OM may experience greater increases in TxB2 than YM 30 min after exercise and may be more predisposed to platelet activation.
authors.affiliation: Department of Physical Education, West Chester University, Pennsylvania 19383.
authors.forename: M K
authors.initials: MK
authors.lastname: Todd
authors.forename: A H
authors.initials: AH
authors.lastname: Goldfarb
authors.forename: R D
authors.initials: RD
authors.lastname: Kauffman
authors.forename: C
authors.initials: C
authors.lastname: Burleson
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D004041:Dietary Fats / Q000494:pharmacology; D002149:Energy Intake / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D015539:Platelet Activation / Q000502:physiology*; D011863:Radioimmunoassay; D013929:Thromboxane B2 / Q000097:blood*; D001620:beta-Thromboglobulin / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D001620:beta-Thromboglobulin; D013929:Thromboxane B2; D002784:Cholesterol