RESUMO
It has been suggested that elderly people are more susceptible to infectious diseases because of immunosenescence. The well-described transient immunosuppressive effect of exercise may increase health risks in such populations. Although resistance training has been recommended to older individuals, little is known regarding its acute effects on immune indexes. This study examined the acute effects of resistance exercise sessions performed at different intensities (50 vs. 80% of one-repetition maximum [1RM]) on salivary immunoglobulin A (IgA), total leukocytes, lymphocytes and their subsets, and the cortisol levels of older women. Fifteen physically independent elderly women (mean age = 67.5 +/- 3.9 years) underwent, in a randomized manner, two experimental sessions comprising resistance exercise for the major muscular groups or one control session without exercise. Session 1 consisted of two sets of 13 repetitions at 50% 1RM, whereas session 2 consisted of two sets of eight repetitions at 80% 1RM. Blood and saliva samples were collected at rest, immediately after, and at 3 and 48 hours after the completion of the sessions. Blood cortisol, total leukocytes, lymphocytes and their subpopulations, and salivary IgA were measured by standard techniques. Overall, resistance exercise sessions failed to provoke significant decline on the examined immune function indexes. Instead, resistance exercise sessions induced significant elevation in salivary IgA levels, but this was not observed after the control session. Also, experimental sessions did not induce significant elevations in blood cortisol. It was concluded that resistance exercise sessions performed at 50 or 80% of 1RM do not present suppressive effects on the studied immune parameters. Conversely, a transient elevation was observed in salivary IgA levels, which requires support in future investigations. Taken together, the observed results suggest that elderly women can engage in resistance training programs without negative acute effects on the studied parameters of the immune system.