Objective And Subjective Assessments Of Exercise Burden In Masters Athletes Are Poorly Correlated

Accurate quantification of exercise volume (burden) is crucial for understanding links between exercise and cardiovascular outcomes in older endurance athletes (EA). Exercise burden, an integral of intensity and duration (MET{middle dot}min), is typically determined from subjective self-reports but has uncertain accuracy. We studied 40 EAs (41 to 69 yrs., 50% female) with >10 yrs. training history, during a typical outdoor cycling training session (42 km). Subjective self-reports were related to cardiac (HR{middle dot}min) and metabolic (MET{middle dot}min) components of exercise burden, monitored continuously. Subjective self-reports were highly variable and underestimated objective metrics of exercise intensity. Discordance was observed between metabolic and cardiac burden as less fit individuals accrued greater cardiac (14039{+/-}2649 vs. 11784{+/-}1132 HR{middle dot}min, P<0.01) but lower metabolic burden (808{+/-}59 vs. 858{+/-}61 MET{middle dot}min, P<0.05) vs. higher fit EA. Caution is advised in interpreting MET{middle dot}min estimates from self-reports, urging objective measurement of cardiac burden for further insights into the risk-benefit relationship of long-term exercise.