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

Abstract

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 (iO2 max), the oxygen uptake at a respiratory exchange ratio of unity (0O2 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 tO2 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 fO2 max by 9-6%. tO2 Max per kg body mass was negatively correlated with body mass. fO2 Max (mean value 130 6 mmol/min) was described in terms ofage, fat free mass, smoking (yes or no), and level of habitual activity (rated 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 fO2 max of individual men an empirical relation based on tO2 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 fO2 at R1.0 (oxygen uptake approximately 73% of maximum). Thus the tO2 max could be estimated in a higher proportion of men than could achieve fO2 max. The estimate is appropriate for assessing exercise capacity in relation to employment. For investigating the determinants ofexercise capacity in groups of subjects the submaximal index, tO2 at R,.o, is more informative.Maximal oxygen uptake (f02 max) reflects the power output for work of 4-10 minutes duration; a high value is a selection criterion for some tasks and in a population is evidence for high customary activity and hence physical fitness. It is measured during progressive exercise up to the point when oxygen uptake reaches a plateau.' An alternative end point is when cardiac frequency attains the predicted maximum2; this presupposes that the reference value for maximal cardiac frequency applies to the study population but it may not. The measurement procedure requires a high level of motivation, causes distress to some subjects, entails medical and electrocardiographic surveillance, and occasionally precipitates myocardial ischaemia or cardiac arrest.3 Indirect estimation of itO2max appears preferable; however, the method should be reproducible and the result equivalent to Accepted 3 August 1987 that obtained by direct measurement. The AO2 max is usually predicted by extrapolating the relation of cardiac frequency on oxygen uptake for progressive submaximal exercise up to the predicted maximal cardiac frequency, but the accuracy of prediction is poor.2 Greater accuracy is achieved using blood lactic acid concentrationv'; however, the requisite blood sampling is not always practicable. In a pilot study prediction from submaximal exercise, cardiac frequency, fat free mass, and...

Indices for detection of changes in cardiorespiratory fitness during exercise training in man

“…The 95 % tolerance limits of individual changes amounted to + 7 beats min-1 and represented a 4 6 % variability. These results showed that the variability attending the measurement of the three indices was small, and was consistent with their previously reported accuracy (Kappagoda et al 1979;Weller et al 1985Weller et al , 1988.…”

“…The most recent of these has been based non-invasively on the measurements of VO at a respiratory exchange ratio of unity (R. 1). This VO /R=1 index can be readily estimated with adequate reproducibility, and, because it correlated with anaerobic threshold it can provide an indicator of capacity for prolonged work (Weller et al 1985(Weller et al , 1988. In addition, the use of HR/ VO elevation or VO /R=1 value avoids the inaccuracy of extrapolations from submaximal exercise to predict maximal indices.…”

“…More recently, a quantitative index of fitness derived from submaximal exercise testing was described. This index was derived as V0, at respiratory exchange ratio (R) of 1 0 (V. /R=,), and was found useful in detecting the level of fitness in groups and individuals (Weller, El-Gamal, Reed, Bridges, Chinn & Cotes, 1985;Weller, El-Gamal, Parker, Reed & Cotes, 1988).…”

The effects of a peripherally selective alpha 2‐adrenoceptor antagonist, MK‐467, on the metabolic and cardiovascular response to exercise in healthy man.

“…For the first minute of exercise there was no externally applied load, thereafter the load was increased to 20 watts and incremented by 20 watts each minute. The exercise was terminated when the respiratory exchange ratio reached a value of unity (approximately 70% of maximal oxygen uptake, [12]). On completion of the exercise test, the subjects returned to the supine position and heart rate and blood pressure were monitored until recovery to pre-exercise resting levels.…”

Relation of lung function and exercise capacity to mood and attitudes to health.

“…Habitual physical activity was rated on a four point scale going from (1) inactive, (2) occasional exercise, (3) regular but non-competitive sport, and (4) participation in competitive sport. 5 Subjects then attended the laboratory for measurement of ventilatory capacity by dynamic spirometry, carbon monoxide transfer factor ofthe lung by the single breath method, and the physiological response to progressive submaximal exercise on a cycle ergometer. A self administered questionnaire scoring anxiety and depression and a semantic differential assessing the subjects's attitudes and beliefs regarding his health were completed.…”