Author(s): KAO, Y.L., LIM, A.Y., WANG, J.S., Institution: CHANG GUNG UNIVERSITY, Country: TAIWAN, Abstract-ID: 397

INTRODUCTION:
Regular exercise ameliorates cardiorespiratory fitness and is associated with immune regulation. Circuit exercise is a relevantly new concept involving multi-station training and targeting multiple major muscle groups. Although previous studies reported benefits of improved physical fitness with lesser fatigue experienced during exercise, most of the research involved resistance exercise or functional training. How aerobic exercise in a circuit pattern affects immunity was not explored. This study aimed to investigate the effects of a 6-week circuit aerobic exercise, as compared to cycling exercise, on exercise performance and neutrophil function.
METHODS:
We recruited and randomized 16 inactive young men to the circuit exercise group (CAT, n=8, cycling-rowing-elliptical training, each 10-minute bout) or cycling exercise group (CYC, n=8, cycling, 3 sets of 10-minute bout) with moderate intensity (60% of heart rate reserve), 5days/week for 6 weeks. Participants’ body composition and cardiorespiratory fitness, were assessed before and after training, using cardiopulmonary exercise testing, respectively. Venous blood samples were collected for analysis of neutrophil subtypes, phagocytosis ability, respiratory burst, and apoptosis using a flow cytometer.
RESULTS:
At baseline, CAT and CYC did not show significant differences in mean age, body composition, and cardiorespiratory fitness (VO2peak=30.97±2.93 and 27.86±1.11, respectively). After training, both groups showed significant improvement in VO2peak (within-group mean difference 4.23±0.8, p<0.001 and 7.91±0.13, p<0.001, for CAT and CYC, respectively). Both groups demonstrated a significant increase in the expression of adhesion molecules (CD16b, p<0.05 and CD88, p<0.05) on neutrophils. CYC, but not CAT, enhanced phagocytosis of Escherichia coli (E. coli) in neutrophils was observed in (p<0.05). However, both training was insufficient in facilitating respiratory burst and the subsequent apoptotic activity.
CONCLUSION:
A 6-week circuit aerobic exercise improves cardiorespiratory fitness in inactive men along with improved expression of adhesion molecules and phagocytosis, but did not regulate the release of oxidant product and subsequent apoptosis of neutrophils.