Although it is generally thought that habitual exercise protects an individual from infections, few careful scientific studies have been conducted. To clarify the influences of physical training on non-specific humoral immunity, both serum opsonic activity, which is a more direct indicator for the strength of non-specific humoral immunity to infections, and serum immunoglobulin and complement levels of 18 healthy male volunteers were assayed before and after a 10-week of training as indices of immuno defense.
The serum levels of three immunoglobulins (IgG, IgA and 1gM) and one complement (C3) were compared prior to and immediately after exercise both before and after training. Paired t-test revealed that before training exercise-induced increases in IgG and C 3 were significant and after training increases in IgG, IgA, IgM and C 3 were significant. But baseline (prior to exercise) levels of these immunoglobulins and complement were significantly suppressed during the training period.
Serum opsonic activity was compared with each other in the same way as serum protein levels. The noutrophilic chemiluminescence Peak Height (PH), which is one of the indicators of serum opsonic activity, was significantly decreased immediately after exercise at the beginning stage of the training. After the training period, serum opsonic activity showed no noteworthy exercise-induced variations and baseline levels were slightly increased during the training period.
These findings suggest that resistance and reactivity to the physical stress are improved and the non-specific humoral immunity, self-defense ability against infections, is considered to be improved by the training.