Predictive accuracy of criteria used to assess maximal oxygen consumption.
To evaluate criteria frequently used to designate an exercise test as maximal, 33 men and 18 women completed progressive incremental cycle ergometry to exhaustion with direct measurement of oxygen consumption (VO2). On a separate day, subjects exercised at 115% of the maximal work rate attained in the first test following a 5-minute warm-up. If VO2 exceeded that of the progressive test by greater than or equal to 150 ml/min, subjects returned on a third day and pedalled at 125% of the first day's work ratepeak. This procedure was repeated until VO2 increased less than 150 ml/min, and defined whether the progressive test was a maximal or nonmaximal test. There were 45 tests that met the criterion for maximum during the progressive test and six nonmaximal tests. Respiratory exchange ratio and 85% age-predicted maximal heart rate were sensitive criteria for a maximal test but were not specific. Attainment of age-predicted maximal heart rate and peak lactate greater than 8 mmol/L were highly specific but insensitive measures of a maximal test. In the absence of a VO2 plateau, age-predicted maximal heart rate and lactate greater than 8 mmol/L can be used as indicators of maximal tests with a high degree of confidence. When age-predicted maximal heart rate or lactate greater than 8 mmol/L are not attained, the test may still be maximal because negative predictive value is low.