The aim of the current study is to analyze and compare oxygen uptake (VO2) and heart rate (HR) in different water exercises. Eight postmenopausal women participated in a set of 4 sessions in water. Eight different exercises were randomly coupled for the 4 sessions. Each exercise was executed at a rate of 60 beats/min for 4 minutes with rest intervals of 30 min. A repeated-measures ANOVA and Bonferroni’s post hoc test were used to test for statistical differences at α < .05. Significant differences were seen in HR and VO2 between some pairs of the 8 exercises. These results suggest that water-exercises classes should be prescribed based on percentages of maximal HR or VO2, not on a fixed cadence, because different exercises correspond to different percentages of maximal effort.