INFLUENCE OF THE LEVEL OF DIETARY-LIPID INTAKE AND MAXIMAL EXERCISE ON THE IMMUNE STATUS IN RUNNERS

Chronic exercise and high fat diets are associated with immune suppres sion. This study compares cellular immune responses at rest and after maximal exercise in runners after eating diets comprised of 17% low fa t (LF), 32% medium fat (MF), and 41% high fat (HF) (4 wk each). V over dotO(2max) increased significantly from the 17% to 41% fat diet. The leukocyte cell counts were significantly increased after exercise. In men, significantly higher proliferative response to phytohemagglutinin (PHA) (P < 0.004) was observed with MF diet, while response to pokewe ed mitogen (PWM) was significantly decreased by MF and HF diets. The n umber of CD8(+) (suppressor) T cells was significantly higher in men a nd exercise increased it significantly, while CD4(+) (helper) T cells were not affected. Natural killer cells number was significantly incre ased 2.5 fold by exercise and with increase in dietary fat. The produc tion of IL-2 by peripheral blood mononuclear cells was significantly h igher in men (P < 0.0001) and increasing dietary fat significantly inc reased IL-2 production (P < 0.001). In men, exercise decreased the lev el of the proinflammatory cytokines (IL-1, IL-6 and TNF-alpha), wherea s in women, with the exception of MF diet for IL-6, exercise had no ef fect. This study indicates that short, intense bouts of exercise in ru nners training 40 miles . wk(-1) have mixed effects on the immune syst em. A high percentage of fat intake (41%) did not have any deleterious effects on the immune system of the well-trained runners.