In this study, thermal behaviours of the athletes were investigated with respect to thermal comfort and exercise intensity. The relationship between an index for analysing thermal comfort (Predicted Mean Vote: PMV) and Rating of Perceived Exertion (RPE) which shows exercise intensity and exhaustion level was evaluated. Eleven moderately trained male athletes (V) over dotO(2max) 54 +/- 9.9 mL.min(-1).kg(-1)) had volunteered for the study (age: 22.2 +/- 3.7 years; body mass: 73.8 +/- 6.9 kg; height: 181 +/- 6.3 cm; Body surface area (BSA): 1.93 +/- 0.1 m(2); body fat: 12.6% +/- 4.2%; (V) over dotO(2max): 54 +/- 9.9 mL.min(-1).kg(-1)). Experiments were carried out by using a cycle ergometer in an air-conditioned test chamber which provided fresh air and had the ability to control the temperature and relative humidity. The study cohort was divided into two groups according to maximal oxygen consumption levels of the participants. Statistical analyses were conducted with the whole study cohort as well as the two separated groups. There was a moderate correlation between PMV and RPE for whole cohort (r: -0.51). When the whole cohort divided as low and high aerobic power groups, an average correlation coefficient at high oxygen consumption cohort decreased to r: -0.21, while the average correlation coefficient at low oxygen consumption cohort increased to r: -0.77. In conclusion, PMV and RPE have a high correlation in less trained participants, but not in the more trained ones. The case may bring to mind that thermal distribution may be better in high aerobic power group in spite of high RPE and thus the relation between PMV and RPE is affected by exercise performance status.