Protective effects of acute moderate exercise on vaccination induced inflammation, arterial function and vaccine efficacy

Acute induced inflammation, using vaccination, reduces flow-mediated vasodilation in the conduit artery in young healthy volunteers. However, this has not been shown in older adults. Immunosenescence with advancing age results in inadequate protection from disease because of ineffective responses to vaccination. An acute bout of moderate aerobic exercise improves arterial and endothelial function and may increase the efficacy of the vaccine in young individuals. Hence, this study sought to evaluate the effect of acute systemic inflammation on endothelial function and wave reflection in older adults. The second aim was to evaluate if acute moderate intensity endurance exercise immediately prior to induced inflammation can prevent the negative effect of acute systemic inflammation on vascular function while augmenting the efficacy of the vaccine. Fifty-nine healthy volunteers between 55 -- 75 years of age were randomly allocated to an exercise or control group. Arterial function and inflammatory markers were measured at baseline, 24 hours and 48 hours after influenza vaccine and sham injections. Antibody titers were measured at baseline and 4 weeks following the Influenza vaccine. CRP increased when measured at 24 and 48 hours and IL-6 increased at 24 hours from baseline after the Influenza vaccine compared to the sham injection while unexpectedly, arterial function was unaltered. There were no significant correlations between changes in inflammatory markers and changes in arterial function. Fitness was related to endothelial function as baseline. Endothelial function was significantly higher in individuals classified as having good fitness compared to the poor fitness category. There was a significant decrease in the endothelial function at 48 hours after vaccination compared to baseline in the fair fitness while there was significant decrease in the endothelial function when measured at 24 and 48 hours as compared to the baseline in good fitness category group. The endothelial function was unaffected in the poor fitness group. There were no differences in the levels of antibody titers against the H3N2 influenza strain between the men and women in exercise group as compared to the control group. However, women in the exercise group had a significantly higher antibody response for H1N1 influenza strain. In conclusion, there was dissociation between inflammation and endothelial function following induced acute systemic inflammation in older adults. The responses of endothelial function to induced acute systemic inflammation were related to fitness. Acute moderate aerobic exercise was not immune-stimulatory in healthy older men, but may serve as a vaccine adjuvant in older women.