Perceived exertion can be lower when exercising in field versus indoors

Purpose Studies indicate that the rated perceived exertion (RPE) during physical exercise can be lower in field environments than indoors. The environmental conditions of those studies are explored. Furthermore, we study if the same phenomenon is valid when cycling indoors versus in cycle commuting environments with high levels of stimuli from both traffic and suburban-urban elements. Methods Twenty commuter cyclists underwent measurements of heart rate (HR) and oxygen uptake (V˙O2) and RPE assessments for breathing and legs, respectively, while cycling in both laboratory and field conditions. A validated mobile metabolic system was used in the field to measure V˙O2. Three submaximal cycle ergometer workloads in the laboratory were used to establish linear regression equations between RPE and % of HR reserve (%HRR) and %V˙O2max, separately. Based on these equations, RPE from the laboratory was predicted and compared with RPE levels at the participants' individual cycle commutes at equal intensities. The same approach was used to predict field intensities and for comparisons with corresponding measured intensities at equal RPE levels. Results The predicted RPE levels based on the laboratory cycling were significantly higher than the RPE levels in cycle commuting at equal intensities (67% of HRR; 65% of V˙O2max). For breathing, the mean RPE levels were; 14.0–14.2 in the laboratory and 12.6 in the field. The corresponding levels for legs were; 14.0–14.2 and 11.5. The range of predicted field intensities in terms of %HRR and %V˙O2max was 46–56%, which corresponded to median differences of 19–30% compared to the measured intensities in field at equal RPE. Conclusion The cycle commuters perceived a lower exertion during their cycle commutes compared to ergometer cycling in a laboratory at equal exercise intensities. This may be due to a higher degree of external stimuli in field, although influences from other possible causes cannot be ruled out.