The objectives of this study were to compare the energy expenditure and heart rate responses between three commercial group fitness classes (group resistance exercise [PUMP]; indoor stationary cycling [RIDE]; and step aerobics [STEP]). Design One-Way Repeated Measures incorporating a Latin Square Design for class randomisation. Methods Ten participants (5 males and 5 females) completed each group fitness class in random order with energy expenditure and heart rate determined using an Actiheart monitor. Results STEP and RIDE produced significantly (p < 0.05) higher average heart rates (HRavg) (85.8 ± 5.1% and 86.4 ± 4.3% of HRmax, respectively) compared to PUMP (73.7 ± 7% of HRmax). HRpeak was also significantly (p < 0.05) higher in STEP and RIDE (97.1 ± 4.7% and 95.6 ± 4.5% of HRmax, respectively) when compared with the PUMP class (90 ± 5.9% of HRmax). Total energy expenditure (TEE), both absolute and relative, were significantly (p < 0.05) higher for STEP (2101.7 ± 560.2 kJ and 0.59 ± 0.07 kJ kg−1 min−1) and RIDE (1880.4 ± 420 kJ and 0.58 ± 0.03 kJ kg−1 min−1) when compared with the PUMP class (1385.1 ± 504 kJ and 0.36 ± 0.07 kJ kg−1 min−1). Conclusions These data suggest that overall exercise intensity and energy expenditure was highly comparable between RIDE and STEP, which suggests these group fitness classes are more effective for developing cardiovascular fitness and assisting with weight management compared with group resistance exercise classes when performed on a regular basis.