Relationship Between the Borg Scale Rating of Perceived Exertion and Leg- Muscle Deoxygenation During Incremental Exercise in Healthy Adults

Introduction: The Borg scale rating of perceived exertion is a reliable indicator and widely used to monitor and guide exercise intensity. We aimed to evaluate the relationships between the Borg scale score and oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) concentrations in the leg muscle as measured by near-infrared spectroscopy ( NIRS) during cardiopulmonary exercise testing (CPET) in healthy adult men. We also investigated the relationships between the Borg scale score and the work rate (WR), heart rate (HR), oxygen uptake (VO2), and minute ventilation (VE). Methods: Participants comprised 12 healthy men. Cardiopulmonary and NIRS parameters were assessed during each minute of CPET and at the end of the test. Results: The Borg scale score was significantly correlated with cardiopulmonary parameters including WR, HR, VO2, and VE during CPET (Rs = 0.87-0.95; p < 0.05). Furthermore, the Borg scale score was significantly correlated with NIRS parameters including O2Hb and HHb levels during CPET (Rs = -0.48 and 0.45, respectively; p < 0.05). Discussion: The Borg scale score is significantly correlated with cardiopulmonary parameters (WR, HR, VO2, and VE), as well as with leg-muscle oxygenation parameters as assessed by NIRS, during CPET in healthy adults. The correlation coefficients obtained from NIRS parameters were lower than those of cardiopulmonary parameters. Conclusions: The Borg scale score might better reflect cardiopulmonary responses than muscle deoxygenation during exercise. These results can aid in the planning of rehabilitation programs for healthy adults.