Effect of Acute High-Intensity Interval Training on Immune Function and Oxidative Stress in Canoe/Kayak Athletes

SIMPLE SUMMARY: High-intensity interval training (HIIT) is a primary training method for canoe/kayak athletes to enhance physical performance. However, intense training regimens can cause immunosuppression due to inflammation, metabolic stress, and oxidative stress. This study aimed to examine the effects of kayaking/canoeing HIIT exercise on immune and oxidative stress measures in athletes. Results showed that acute sprinting interval training on a kayak can affect immune cell count and oxidative stress biomarkers. Coaches and sports science professionals should consider these findings, as high training frequency or inadequate recovery periods between HIIT sessions can temporarily suppress immune function. ABSTRACT: The aim of this study was to investigate the effects of acute high-intensity interval training (HIIT) on immune function and oxidative stress in male canoe/kayak athletes who were well trained. A total of 22 participants were voluntarily recruited with an age range of 15.9 ± 2.3 years, height of 172.2 ± 5.5 cm, body mass of 63.30 ± 6.95 kg, and body fat of 13.77 ± 3.76%. The modified Wingate kayaking test on a kayak ergometer was performed by all participants. Blood samples were collected at three different time points: before the test (Pre-T), immediately after (Post-T), and 3 h post-test (Post-3 h). Saliva samples were collected at two different time points: before the test (Pre-T) and 3 h after the test (Post-3 h). Results indicated that acute canoe/kayak ergometry HIIT had significant effects on the percentages and counts of leukocytes, neutrophils, lymphocytes, and lymphocyte subsets. Additionally, it resulted in increased total LPS-stimulated neutrophil elastase release and alterations in plasma concentrations of superoxide dismutase, catalase, and TBARS. These findings suggest that conventional kayak HIIT regimens can have short-term effects on immune function and induce oxidative stress in athletes.