An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass

Abstract

We have reported using near‐infrared spectroscopy that an increase in prefrontal oxygenated‐hemoglobin concentration (Oxy‐Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the cardiovascular responses depending on exercise effort. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation by longitudinal comparisons in 13 subjects. The subjects performed one‐ or two‐legged cycling at various relative intensities (20%, 35%, 45%, and 60% of maximal voluntary exercise intensity) for 1 min. The prefrontal Oxy‐Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one‐ and two‐legged cycling were augmented (P<0.05) in proportion to exercise intensity and/or muscle mass recruitment. However, the increase in prefrontal Oxy‐Hb seemed independent of exercise intensity. When the rating of perceived exertion was equal, the increase in prefrontal Oxy‐Hb was not different (P>0.05) between one‐and two‐legged cycling. Furthermore, no correlations (P>0.05) were found between the increase in prefrontal Oxy‐Hb and exercise intensity or rating of perceived exertion. It is likely that increased prefrontal oxygenation at the start of cycling exercise does not represent the final output of central command descending to the autonomic nervous system.Support or Funding InformationThis study was funded by Grant‐in‐Aid (15H03061) for Scientific Research (B) from the Japan Society for the Promotion of Science (JSPS).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.