AUTHOR=Nakahara Hidehiro , Ueda Shin-ya , Miyamoto Tadayoshi 

TITLE=Low Frequency Severe-Intensity Interval Training Markedly Alters Respiratory Compensation Point During Incremental Exercise in Untrained Male

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.01100

DOI=10.3389/fphys.2020.01100

ISSN=1664-042X

ABSTRACT=<p>This study investigated the effect of low-frequency severe-intensity interval training on the respiratory compensation point (RCP) during incremental exercise test. Eighteen healthy males (age; 20.7 ± 2.2 years, range 18 to 29 years, height; 174.0 ± 5.6 cm, weight; 68.8 ± 13.5 kg) were randomly assigned to an interval training group or a control group. Interval training was conducted once weekly for 3 months. Each session consisted of three bouts of bicycle ergometer exercise at 80% maximum work rate until volitional fatigue. Before (baseline) and after the 3-month intervention, incremental exercise test was performed on a bicycle ergometer for determination of ventilatory threshold (VT), RCP, and peak oxygen consumption (V̇<sub>O</sub><sub>2</sub> peak). The training program resulted in significant increases of V̇<sub>O</sub><sub>2</sub> peak (+ 14%, <italic>p</italic> &lt; 0.001, <inline-formula><mml:math id="INEQ1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">η</mml:mi><mml:mrow><mml:mtext>p</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msubsup></mml:math></inline-formula> = 0.437), oxygen consumption (V̇<sub>O</sub><sub>2</sub>) at VT (+ 18%, <italic>p</italic> &lt; 0.001, <inline-formula><mml:math id="INEQ2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">η</mml:mi><mml:mrow><mml:mtext>p</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msubsup></mml:math></inline-formula> = 0.749) and RCP (+ 15%, <italic>p</italic> = 0.03, <inline-formula><mml:math id="INEQ3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">η</mml:mi><mml:mrow><mml:mtext>p</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msubsup></mml:math></inline-formula> = 0.239) during incremental exercise test in the training group. Furthermore, a significant positive correlation was observed between the increase in V̇<sub>O</sub><sub>2</sub> peak and increase in V̇<sub>O</sub><sub>2</sub> at RCP after intervention (<italic>r</italic> = 0.87, <italic>p</italic> = 0.002) in the training group. Tidal volumes at VT (<italic>p</italic> = 0.04, <inline-formula><mml:math id="INEQ4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">η</mml:mi><mml:mrow><mml:mtext>p</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msubsup></mml:math></inline-formula> = 0.270) and RCP (<italic>p</italic> = 0.01, <inline-formula><mml:math id="INEQ5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">η</mml:mi><mml:mrow><mml:mtext>p</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msubsup></mml:math></inline-formula> = 0.370) also increased significantly after intervention compared to baseline. Low-frequency severe-intensity interval training induced a shift in RCP toward higher work rate accompanied by higher tidal volume during incremental exercise test.</p>