[Heart rate, blood lactate concentration and subjective stress perception in submaximal running: new nomograms for assessment of endurance capacity].

Considering the protective effect of physical activity against coronary heart disease, the estimation of endurance capacity is not only recommended for sportsmen but is also useful for exercise counselling of unfit persons. Endurance capacity can be estimated with test protocols leading to complete exhaustion, or by submaximal test procedures. Submaximal tests have the advantage of putting less stress on subjects than maximal test protocols; on the other hand, they are less accurate. As a complement to traditional submaximal test protocols based on heart rate analysis, a new submaximal protocol is proposed based on measurements of capillary blood lactate concentration during exercise. Incremental tests of 319 men with wide variation of endurance capacity were used to calculate nomograms of the typical pattern of exercise-induced increase in capillary blood lactate concentration, heart rate, and rating of perceived exertion in relation to endurance capacity. The running velocity eliciting a capillary blood concentration of 4 mmol/l lactate was selected as the parameter for endurance capacity. With the help of these nomograms, the 4 mmol/l-velocity could be estimated with submaximal values of lactate, heart rate or rating of perceived exertion. The appropriateness of the nomograms was checked against the data of 100 independent maximal treadmill tests. Estimation of 4 mmol/l-velocity with submaximal lactate values showed good precision (with a small standard deviation of +/-0.17 m/s); in contrast, the estimation of endurance capacity with submaximal values for heart rate and rating of perceived exertion showed substantially larger standard deviations (approximately +/-0.56 m/s). We conclude that, for estimation of endurance capacity from submaximal running values, the nomogram for blood lactate concentrations can be recommended.