Effect of exercise, aging and functional capacity on acute secretory immunoglobulin A response in elderly people over 75 years of age.

Background: Age-associated decline in immune function and regulation, referred to as immunosenescence, brings about an increased incidence of infectious diseases in the aged; however, there are few data on the effect of aging and exercise on mucosal immune function in elderly people. Moreover, there is no evidence on whether the change in functional capacity affects mucosal immunity in elderly people. Therefore, the aim of the present study was to examine the effects of exercise, aging and functional capacity on mucosal immune function in elderly people over 75 years of age.

Methods: The subjects were 92 community-dwelling elderly women aged over 75 years who lived in a rural community in Miyagi Prefecture. The subjects periodically performed approximately 20 min of low intensity exercise. Saliva samples were collected before and after exercise, and saliva flow (SF), secretory immunoglobulin A (SIgA) concentration (SIgA-C) and SIgA secretion rate (SIgA-SR) were determined. The Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) was used to measure functional capacity.

Results: In comparison with before exercise, SF, SIgA-C and SIgA-SR were significantly increased after exercise in elderly subjects. In addition, when low and high value groups of resting SIgA levels were compared, acute SIgA responses were observed only in the low value group; however, there was no significant effect of aging and decline in functional capacity on exercise-induced SIgA response.

Conclusion: These results suggest that resting SIgA levels influence the mucosal immune function response to exercise in elderly people over 75 years of age.