INTRODUCTION: The strong physical demands that are required of lifeguards during rescues also requires an accurate self-perception of one's fitness level to be able to regulate the intensity of effort.
OBJECTIVES: The aim of this study was to determine the real aerobic capacity (RAC) and to compare it with two self-reported measurements: subjective appraisal of aerobic capacity (SAAC) and appraisal of physical exercise (APE).
METHODS: Fifty-two professional lifeguards were included in the study. For an objective assessment of RAC, the lifeguards' maximum oxygen uptake (VO2max) values were measured during treadmill stress tests. A fitness assessment questionnaire (FAQ) was used to obtain the SAAC and APE values.
RESULTS: We found a statistically significant association between the APE and RAC variables in the contingency analysis (p < 0.001). In total, 93.7% of the lifeguards who obtained a VO2max value below 43 ml·kg(-1)·min(-1) considered their aerobic capacity to be high or very high.
CONCLUSION: This self-perception error of his true aerobic capacity could lead to premature fatigue during a rescue, endangering both his life and the life of the victim. These data may help lifeguards and beach managers to become aware of the need to know lifeguards' true physical conditions through testing and structured training programs.