A practical method of estimating an individual's maximal oxygen intake

The premises upon which simple methods for estimating an individual's maximum oxygen intake are based have boon tested. These premises are : (a) that heart rate and oxygen intake are linear functions of each other throughout the entire range of work up to the individual's maximum; (b) that oxygen intake of the individual deviates very little from the mean straight line relating oxygon intake and rate of work for the population, so that the oxygon intake for a task performed against gravity can be estimated with reasonable precision from the rate of work; and (c) that the individual variability of maximum heart rate round the mean for the population is sufficiently small to use the moan in a routine test procedure without the introduction of largo errors. Premises (b) and (c) are fully substantiated by the results reported here, Premise (a) is not strictly valid, as there is a bias of the order of 03 1. oxygon/min in the straight line relating heart rate and oxygen intake at high levels of work in most individuals. The errors involved in the method proposed by Åstrand (1954) based on these premises have been examined and compared with those of an alternative procedure described in the present paper. The variance of maximum oxygen intake using the Astrand method, duo to errors in measurement of heart rate alone, is of the order 0·53, compared with 0·26 of the procedure described in this paper. In addition, one measurement only of heart rate in the Åstrand method introduces a bias of about 0·3 1. oxygen/min in the estimate of an individual maximum oxygon capacity of 3·0 l/min. The variance of maximum oxygen intake by the present method can be reduced by fitting a straight line by least squares to plots of four pairs of heart rate and oxygen intake values at four rates of work. © 1961, Walter de Gruyter. All rights reserved.