Effect of exercise on in vitro immune function: a 12-month randomized, controlled trial among postmenopausal women.

Publication Type:

Journal Article

Source:

Journal of applied physiology (Bethesda, Md. : 1985), Volume 104, Issue 6, p.1648-55 (2008)

Keywords:

2008, Aged, Cell Proliferation, Cells, Cultured, Center-Authored Paper, Cytotoxicity, Immunologic, Exercise, Female, Health Behavior, Humans, Immunoglobulins, K562 Cells, Killer Cells, Natural, Lymphocyte Activation, Lymphocyte Count, Middle Aged, Obesity, Overweight, PHENOTYPE, Postmenopause, Prevention Center Core Facility, Public Health Sciences Division, Shared Resources, T-Lymphocytes, Time Factors

Abstract:

Cross-sectional studies suggest that moderate physical activity is associated with enhanced resting immune function; however, few randomized controlled trials have investigated this link. We investigated the effect of 12-mo aerobic exercise, relative to stretching control, on in vitro immune function in a randomized, controlled trial of 115 postmenopausal, overweight, or obese sedentary women, aged 50-75 yr. The exercise goal was > or =45 min/day, 5 days/wk. Control women participated in 1 day/wk stretching classes. Immune markers (natural killer cell cytotoxicity, T-lymphocyte proliferation, immune cell counts and phenotypes, and serum immunoglobulins) were assessed at baseline, 3 mo, and 12 mo under strict blood-draw criteria. General estimation equations evaluated intervention effects at 3 and 12 mo, controlling for baseline. Of the 115 women who began the trial, blood samples were available from 109 at 3 mo (95%) and 108 at 12 mo (94%). From baseline to 12 mo, the exercise group participated in 87% of the prescribed physical activity minutes per week and increased maximal O(2) uptake by 13.8%; controls experienced no change in fitness. The main outcomes, natural killer cell cytotoxicity and T-lymphocyte proliferation, did not differ between groups at 3 and 12 mo. Secondary outcome and subgroup (e.g., stratification by baseline categories of body mass index, immune status, C-reactive protein, and age) analyses did not show any clear patterns of association. This 12-mo randomized, controlled trial showed no effect of aerobic exercise on in vitro immune function, despite excellent retention, high adherence, and demonstrable efficacy of the exercise intervention.