Chronic resistance exercise training improves natural killer cell activity in older women

Background. Regular exercise has been reported to slow the age-associated declines in natural killer cell activity (NKCA). To evaluate this response, we recruited older, postmenopausal women (65-85 years old) to fill one of two groups: training (10 weeks of resistance exercise; TR) or control. Methods. Blood samples were collected from an arm vein in the TR group at rest (PRE), immediately following (POST), and 2 hours (211) following an acute bout of resistance exercise both before (BEFORE) and after (AFTER) training. Leukocytes and NKCA were determined by flow cytometry and a whole blood Cr-51 release assay, respectively. Results. Acute exercise increased total leukocyte (p <.05), CD8 (p <.05), CD4 (p <.05), and CD56 counts (p <.05), but there was no effect of training. NKCA was greater TR-AFTER-PRE (136%), -POST (80%), and -2H (127%) compared to similar values from TR-BEFORE (p <.05). Conclusion. Increased resting NKCA after chronic resistance training suggests that immunity has been improved.