This study was carried out to examine the effects of forced running exercise on the immune functions of male ICR mice. Mice aged 4 weeks were divided into two groups: a non-exercise group (control) and a group given forced running exercise (exercise group). The exercise applied was forced running at 15m/min on a flat floor without any slope for 60min a day. The duration of exercise was 5 days per week for 12 weeks.
The results obtained were as follows:
1) After 12 weeks of forced running exercise, the weight of the anterior tibialis muscle and succinate dehydrogenase activity in the anterior tibialis muscle increased significantly (p<0.01) in the exercise group compared with the control group. A tendency for thymus weight to increase was shown in the exercise group, and liver and spleen weights were significantly (p<0.01) greater than in the control group.
2) The potentiation of phagocytic function of the reticulo-endothelial system, examined by the carbon clearance method, was seen in the exercise group.
3) The ability of peritoneal macrophages (Mφ) to phagocytose latex beads significantly increased (p<0.01) in the exercise group. The acid phosphatase activity of peritoneal Mφ remained in both groups. However, lactate dehydrogenase activity of peritoneal Mφ significantly increased (p<0.01) in the exercise group compared with the control group.
4) The proliferation of splenocytes induced by Con A in the exercise group significantly increased (p<0.01) compared with the control group.
These results suggested that endurance training could enhance immune functions and might also intensify the function of the host defense system in mice.