Cardiometabolic response to high intensity functional training versus rowing-based high intensity interval training

This study compared the cardiometabolic response between rowing high intensity interval training (HIIT) and high intensity functional training (HIFT). Twenty two adults (age and $\dot{\mathrm{V}}{\mathrm{O}}_2\mathrm{m}\mathrm{a}\mathrm{x}$ ​= ​[25 ​± ​7] yr and [40 ​± ​9] mL/kg/min) underwent incremental exercise on a rowing ergometer to assess $\dot{\mathrm{V}}{\mathrm{O}}_2\mathrm{m}\mathrm{a}\mathrm{x}$ and peak power output (PPO). Subsequently, they underwent rowing HIIT (six 1 minutes [min] efforts at 85% PPO with 75 seconds [s] recovery) or HIFT (six 1 ​min efforts including pushups, jump squats, mountain climbers, and air squats with 75 ​s recovery). Gas exchange data, heart rate (HR), and blood lactate concentration (BLa) were acquired during exercise and post-exercise. These regimens elicited 92%–96% HRmax, with higher peak HR ([174 ​± ​14] b/min vs. [167 ​± ​15] b/min, p ​= ​0.002) and time spent ≥ 85% HRmax ([6.1 ​± ​2.2] min vs. [5.0 ​± ​2.8] min, p ​= ​0.03) for HIFT versus rowing HIIT. Results showed similar peak $\dot{\mathrm{V}}{\mathrm{O}}_2$ between HIFT and HIIT ([81 ​± ​9] vs. [82 ​± ​8] $\dot{\mathrm{V}}{\mathrm{O}}_2\mathrm{m}\mathrm{a}\mathrm{x}$, p ​= ​0.72), yet lower mean $\dot{\mathrm{V}}{\mathrm{O}}_2$ ([1.73 ​± ​0.38] L/min vs. [1.93 ​± ​0.50] L/min, p ​< ​0.001). Mean and peak ventilation $({\dot{\mathrm{V}}}_{\mathrm{E}})$ was significantly higher (p ​< ​0.05) with HIFT ([62 ​± ​13] L/min and [84 ​± ​18] L/min vs. [53 ​± ​15] L/min and [73 ​± ​19] L/min). BLa was significantly higher with HIFT versus rowing HIIT (p ​< ​0.001) and was elevated 15 ​min post-exercise ([7.0 ​± ​3.0] mM vs. [3.5 ​± ​1.1] mM). In healthy, active adults, HIFT elicits vigorous intensities similar to traditional HIIT.