Applicability of maximal oxygen consumption criteria in obese, postmenopausal women.

Abstract

This study examines the applicability of using three standard criteria (age-predicted maximal heart rate [HRmax], respiratory exchange ratio [RER>1.10], and plateau in oxygen uptake [Vo(2)] for the measurement of maximal oxygen consumption (Vo(2)max) in postmenopausal women. One hundred eight postmenopausal (60 +/- 6 years), overweight and obese (body mass index [BMI] = 33 +/- 4 kg/m(2)), sedentary (Vo(2)max = 19 +/- 3 ml/kg/min) women underwent one exercise test (Bruce protocol), and 71 of these women underwent a second test (modified Balke protocol). On test 1, 69 (64%) women achieved age-predicted HRmax, 61 (57%) reached an RER>1.10, and 16 (15%) achieved a plateau in Vo(2) (<2 ml/kg/min change). Women who reached age-predicted HRmax and reached an RER of at least 1.10 had a higher peak Vo(2) (p <0.01) than women who did not meet these criteria. There was no difference in the highest V02 obtained between women who did and did not achieve a plateau in Vo(2) during test 1 (p = 0.55). Resting HR, HRmax, and RER were similar between the two tests. On average, peak Vo(2) was higher on the second test (p <0.01). However, Vo(2)max was not different between exercise tests in women who achieved at least two of the three criteria on both tests (n = 24; test 1, 19.4 +/- 3.4; test 2: 19.8 +/- 3.7 ml/kg/min; p = NS). In addition, Vo(2)max was similar between the two exercise tests in 14 women who reached a plateau on the second test but did not reach a plateau on the first test (19.2 +/- 3.3 vs. 19.6 +/- 4.2 ml/kg/min; p = NS). We conclude that achievement of a plateau in Vo(2) is not a necessary criterion for a valid measurement of Vo(2)max in overweight and obese, sedentary, postmenopausal women.