Absolute or relative work load in exercise testing--significance of individual differences in working capacity

A commun multistage bicycle ergometer test (50 W increases every third minute until exhaustion) was analysed for significance of individual differences in working capacity in six young borderline hypertensive and six young normotensive males. From measurements of O2 uptake (VO2) during each of the prescribed work rates, up to and including maximal effort, relationships with relative work load (% VO2 max) could be established for each of the variables observed in the study. An alternative procedure was tested in which the relative work load was established on the basis of the individual's maximal mechanical power output (Wmax). In heavy exercise the variation coefficients for some variables were nearly halved when observed at a given relative (% VO2 max or % Wmax) rather than absolute (number of watts) exercise level. In light exercise the effect of this normalization was negligible. The two expressions of relative work load were closely correlated. Relative work load in % VO2 max could be predicted from the relative work load in % Wmax with an average standard error of estimate of 2.8%. Exercise heart rate and rate of perceived exertion (Borg scale) were also significantly correlated with relative work load. However, these latter variables were less precise as indicators of relative work load, the standard error of estimates being 3 and 5 times larger than that of % Wmax, respectively. The procedure of establishing relative work load on the basis of Wmax may be of value if a precise setting is desirable when measurements of VO2 are impracticable. The method may also be of use if an individual's HR-work load relationship is abnormal, for example because of medication.(ABSTRACT TRUNCATED AT 250 WORDS)