The purpose of this study was to investigate the relationship of the Borg scale score with leg-muscle oxygenated haemoglobin (O2Hb) and deoxygenated haemoglobin (HHb) levels on near infrared spectroscopy (NIRS) and the work rate, heart rate (HR), oxygen uptake (VO2) and minute ventilation (VE) during supine cardiopulmonary exercise testing (CPET) in healthy adult men. We also investigated the relationships between the leg-muscle O2Hb and HHb levels and the work rate during supine CPET. Fifteen healthy male volunteers (mean age, 20.7 ± 0.6 years; mean height, 172.1 ± 5.7 cm; mean body weight, 61.7 ± 6.6 kg) participated in this study. The cardiopulmonary and NIRS parameters were assessed during each minute of supine CPET and at the end of the test. The Borg scale score significantly correlated with the work rate, HR, VO2, and VE during supine CPET (Rs = 0.86-0.94, p < 0.05). Furthermore, the Borg scale score significantly correlated with the leg-muscle O2Hb and HHb levels during supine CPET (Rs = -0.6, and 0.8, respectively; p < 0.05). The leg-muscle O2Hb and HHb levels had significant correlations with the work rate (R = -0.62 and 0.8, respectively; p < 0.05). The Borg scale score may be used to determine the rating of perceived exertion, whole-body fatigue and local-muscle fatigue during supine exercise. Moreover, leg-muscle oxygenation is associated with the work rate in supine exercise, similar to that observed in upright exercise.
Keywords: Borg scale score; Fatigue; Leg muscle hemoglobin oxygenation; NIRS.
© 2022. Springer Nature Switzerland AG.