Indirect estimation of maximal oxygen uptake for study of working populations.

A total of 345 shipyard workers (aged 23 to 47) volunteered to perform progressive exercise on a cycle ergometer (15 W/min increments) up to the symptom limited maximum. The results were used to obtain maximal oxygen uptake (nO2 max), the oxygen uptake at a respiratory exchange ratio of unity (nO2 at R1.0), and cardiac frequency at an oxygen uptake of 45 mmol/min (fC45). In this group 156 men (45% of initial population) attained nO2 max as defined, 108 (31%) withdrew or did not exercise maximally, and 49 (14%) had transient electrocardiographic abnormalities. For the 156 men extrapolation of the relation of cardiac frequency on oxygen uptake to the predicted maximal cardiac frequency resulted in overestimation of nO2 max by 9.6%. nO2 Max per kg body mass was negatively correlated with body mass. nO2 Max (mean value 130.6 mmol/min) was described in terms of age, fat free mass, smoking (yes or no), and level of habitual activity (rated 1 to 4): the standard error of the estimate (SEE) was 17.3 mmol/min (R2 0.42); the equation was suitable for reference values. For estimating the nO2 max of individual men an empirical relation based on nO2 at R1.0, fC45, fat free mass, and % body fat had an SEE of 12.1 mmol/min (R2 0.67). Seventy six per cent of men (88% of those who exercised) attained nO2 at R1.0 (oxygen uptake approximately 73% of maximum). Thus the nO2 max could be estimated in a higher proportion of men than could achieve nO2 max. The estimate is appropriate for assessing exercise capacity in relation to employment.(ABSTRACT TRUNCATED AT 250 WORDS)