AUTHOR=Zhao Kegang , Hu Zhongyi , Wang Tao , Tian Lei , Wang Maoye , Liu Ruijiang , Zuo Chongwen , Jihua Wang 

TITLE=Acute effects of two different work-to-rest ratio of high-intensity interval training on brain-derived neurotrophic factor in untrained young men

JOURNAL=Frontiers in Physiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.988773

DOI=10.3389/fphys.2022.988773

ISSN=1664-042X

ABSTRACT=Background: Aerobic exercise could produce a positive effective on the brain by releasing brain-derived neurotrophic factor (BDNF). In untrained healthy humans there seems to be a linear correlation between exercise duration and the positive effect of acute aerobic exercise on BDNF levels. Therefore, we performed two different duration of high-intensity interval training pro-tocols (HIIT), both known to improve cardiovascular fitness, to determine whether then have a similar efficacy in affecting BDNF levels.
Methods: 12 untrained young males (aged 23.7±1.8 years), participated in a randomized con-trolled cross-over trail. They underwent two different work-to-rest ratio HIIT protocols: HIIT1(30minutes, 15 intervals of 1minute efforts at 85-90% VO2max with 1minute of active recovery at 50-60% VO2max) and HIIT2(30minutes, 10 intervals of 2minutes efforts at 85-90% VO2max with 1minute of active recovery at 50-60% VO2max). Serum cortisol, BDNF were collected at baseline, immediately following intervention, and 30minutes into recovery for measurements using a sandwich ELISA method, blood lactate was measured by using a porta-ble lactate analyzer.
Results: Our results showed that the similar serum BDNF change in both HIIT protocols, with maximal serum BDNF levels being reached toward the end of intervention. There was no signif-icant change in serum BDNF from baseline after 30minutes recovery. We then showed that both HIIT protocols significantly increase blood lactate and serum cortisol compared with base-line value (HIIT1 p < 0.01; HIIT2 p < 0.01), with HIIT2 reaching higher blood lactate levels than HIIT1 (p = 0.027), but no difference was observed in serum cortisol between both protocols. Moreover, changes in serum BDNF did correlate with change in blood lactate (HIIT1 r=0.577, p < 0.05; HIIT2 r = 0.635, p < 0.05), but did not correlate with the change in serum cortisol.
Conclusions: BDNF levels in untrained young men are significantly increased in response to different work-to-rest ratio of HIIT protocols, and the magnitude of increase is exercise dura-tion independent. Moreover, the higher blood lactate did not raise circulating BDNF. Therefore, given that prolonged exercise causes higher levels of cortisol. we suggest that the 1:1work-to-rest ratio of HIIT protocol might represent a preferred intervention for promoting brain health.