Background: Dyspnea influences cerebral blood flow of working memory and emotions. The purpose of this study was to elucidate whether there is a difference in cerebral blood flow that affects dyspnea between the left and right hemispheres.

Methods: This study was a prospective observational study. 26 healthy males performed three breath-holding tests. During breath-holding tests, subjects were measured oxyhemoglobin (oxy-Hb) by near-infrared spectroscopy (NIRS) and the skin conductance response (SCR) by polygraphic recording. The breath-holding test measured holding time (maximum time) and dyspnea. The NIRS measured oxy-Hb of the emotion and working memory regions of the left and right hemispheres.

Result: Third maximum time (47.6±22.4 sec) was significantly longer than first maximum time (37.8±16.1sec, p<0.05). The maximum dyspnea scores were 7.4 for the first and 7.6 for the third. Emotional oxy-Hb of left and right were significantly higher at maximum time (Borg 7) than at rest in all three times (p<0.05). Working memory Oxy-Hb of left and right were no change between rest and maximum time. SCR was significantly higher at maximum time than at rest for all three times (p<0.05). There was no difference in working memory Oxy-Hb between the left and right for all three times. Right Emotional oxy-Hb (0.40±0.31) at maximum time was significantly higher than left oxy-Hb (0.26±0.36, p<0.05) at first time. Right Emotional oxy-Hb (0.20±0.28) at third time was significantly lower than first time oxy-Hb (0.40±0.31, p<0.05). No difference was observed in oxy-Hb in the left emotional and working memory.

Conclusion: These findings suggest that severe dyspnea increases right emotional cerebral blood flow.Habituation to dyspnea reduces right emotional cerebral blood flow.