Background/Purpose Ratings of perceived exertion (RPE) reported during maximal graded exercise testing (GXT) may predict maximal heart rate (HR) and maximal oxygen consumption (VO2max) at higher grades of RPE intensity. In theory, Borg's RPE unit can be multiplied by ten to create an adjusted RPE and used to approximate HR. This study compared adjusted RPE values of trained runners to their actual HR during GXT.
Method A modified incremental Bruce protocol was employed to measure VO2max using a TrueOne 2400 Metabolic Measurement System during GTX on a Quinton MedTrack CR 60 motor-driven treadmill. Twelve male (M VO2max = 58.58 ml kg min, SD= 11.48) and seven female (M VO2max = 49.8 ml kg min, SD= 7.12) run-trained university students (M age= 23.78 years, SD= 4.75) reported RPE at the end of each workload during GXT. RPE and HR were compared at 50, 60, 75, 85, and 100% of VO2max.
Analysis/Results Subjects underestimated their exercise intensity by 49.1, 16.8, 31.1, 17.7, and 1.7 % at 50, 60, 75, 85, and 100% of VO2max respectively. Repeated measures ANOVA indicated a significant difference (p< .001) between adjusted RPE and actual HR. Pairwise comparisons indicated that adjusted RPE and actual HR differed significantly at 50, 60, 75, and 85% (p< .001 for each) but not at 100% of VO2max (p= .097).
Conclusions Use of the Borg RPE scale to predict intensity during sub maximal exercise may not be appropriate for trained runners because they may have a blunted perception of their physical exertion.