earticle

영어

Regular running and strength training are the best ways to improve aer-obic capacity and develop the size of skeletal muscles. However, un-controlled physical activities can often lead to an undertraining or over-training syndrome. In particular, overtraining causes persistent fatigue and reduces physical performance due to changes in the various phys-iological and immunological factors. In this study, we gave an exhaus-tive submaximal endurance or resistance exercise to participants and investigated the relationship between physical stress (cortisol level in blood), oxidative stress (intracellular ROS accumulation), and adaptive immune response (CD4:CD8 ratio). Ten male volunteers were recruited, and performed a submaximal endurance or resistance exercise with 85% of VO2max or 1-repetition maximum until exhaustion. Blood sam-ples were collected at rest, and at 0 and 30 min after the exercise. Corti-sol levels, oxidative stress, and immune cell phenotypes in peripheral blood were evaluated. Cortisol levels in the sera increased after the ex-haustive endurance and resistance exercises and such increments were maintained through the recovery. Intracellular ROS levels also in-creased after the exhaustive endurance and resistance exercises. The ratio of CD4+ T cells to CD8+ T cells after each type of submaximal ex-ercise decreased compared with that at the resting stage, and returned to the resting level at 30 min after the exercise. In this study, an exhaus-tive endurance or a resistance exercise with submaximal intensity caused excessive physical stress, intracellular oxidative stress, and post-exercise immunosuppression. This result suggests that excessive physical stress induced temporary immune dysfunction via physical and oxidative stress.