The long-term training decreases cell-mediated immunity

Abstract

[Introduction] The prevalence of upper respiratory infection has been reported to increase due to excessive exercise. Although the effects of short-term exercise load on immune function have been studied, a few reports have evaluated the effects of prolonged exercise load. Therefore, we focused on a rugby club training camp, in order to examine the effects of prolonged high-intensity exercise load on cell-mediated immunity.

[Methods] The subjects were 10 male university students who were members of rugby football clubs. Blood samples were collected from the subjects before and after a 25-day training camp. The count of T helper 1 (Th1) and T helper 2 (Th2), Th1/Th2 ratio, noradrenaline were measured.

[Results] Th1 (pre: 20.5 ± 1.0%, post: 16.8 ± 0.8%, p < 0.01) and Th1/Th2 ratio (pre: 11.4 ± 0.9%, post: 8.8 ± 0.4%, p < 0.01) showed a significantly low value after the camp in comparison with before the camp. Th2 (pre: 1.9 ± 0.1%，post: 1.9 ± 0.1%, n.s.) and Noradrenaline (pre: 393.5 ± 36.5 pg/mL, post: 482.4 ± 38.3 pg/mL, p = 0.057) showed no significant difference.

[Conclusions] In this study involving male university students, Th1 and the Th1/Th2 ratio decreased after the 25-day exercise load, suggesting a suppression in cell-mediated immunity.