The aim of present study was to analyze the oxygen uptake, the heart rate, and the energetic expenditure of women in two water aerobics routines: continuous and interval. The sample comprised ten voluntary active women who performed two water aerobics routines with a minimal interval of 48 hours and randomized order. Each routine was performed with the same exercises and duration, along 32 minutes. The intensity was controlled through Borg’s rate of perceived exertion (RPE), adopting RPE 13 for continuous routine and RPE 17 and RPE 9 for interval routines. It was utilized the paired t test, with the level of significance established at α < .05 (SPSS version 13.0). For all variables, it has been found in interval significantly higher values than continuous routine. Thus, it can be concluded that the interval routine is more intense, being indicted for people looking for a major energy expenditure.