The purpose of this study was to determine the effect of 12 wks of aerobic training on resting lymphocyte number and proliferation, and immunoglobulin and cytokine levels. Eleven college-aged males (training group = EX) performed 30 min of cycling at 75 % of VO2peak, 3 days/wk with VO2peak assessment and blood samples taken at 0,8 and 12 wks. A group of 10 sedentary controls (CT) underwent the same testing protocol. Lymphocyte proliferation response to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) was quantified as a stimulation index (SI) based on the ratio of stimulated versus control cultures, and as total counts per min (CPM). Immunoglobulin (Ig) levels (IgC, IgA, and IgM), and lymphocyte counts were also determined. There was a significant increase in VO2 in the EX group (41.0 ± 1.8 vs. 46.3 ± 1.4 ml · kg-1 · min-1 pre and post training, respectively). Training had no effect on the PHA SI for the EX group (23.9 ± 3.3, 27.7 ± 4.1, and 26.3 ± 4.0 at 0,8 and 12 wks, respectively), or the responses of the CT group (28.8 ± 6.0, 23.9 ± 3.1, and 30.6 ± 4.3). No changes were observed for the PWM SI. Significant increases were observed in the CPM for both groups. No differences in the Ig or lymphocyte levels were found during the study. These data indicate that 12 wks of moderate endurance training did not alter resting immune function as determined by mitogen stimulated lymphocyte proliferation, total circulating lymphocytes, or Ig levels.
Key words
Exercise - immune system - mitogenesis - immunoglobulins
