Cardiorespiratory Responses to High Intensity Interval Shallow Water Exercise

The purpose of this study was to investigate the cardiorespiratory responses to shallow water, high intensity interval exercise (SW-HIIE). Interestingly, no studies have investigated the physiological responses of performing HIIE in a water medium. Thus, the main question of this investigation was the following: What is the physiological load imposed on the human body during an acute SW-HIIE session? Physically active females, n=9 and 26+6 yrs, volunteered for this descriptive study. Volunteers performed a familiarization trial, an incremental maximal shallow water exercise test, and a SW-HIIE session. Participants were submerged to ~75 percent of stature (axillary level). SW-HIIE consisted of 4 X 4 minute segments with one minute recovery in between each segment. Each segment consisted of 8 X 20 seconds of maximal physical effort with 10 seconds of rest between each effort. Indirect calorimetry (Parvo-Medic metabolic analyzer) was employed to assess metabolic response and heart rate was monitored via telemetry (Polar technology). SW-HIIE elicited an overall oxygen uptake response of 2.0+0.2 lO2.min-1 (73+5% of peak aerobic capacity), nearly eight times above resting metabolic rate, while overall heart rate (HR) response was 156+8 bpm (86+2% HR peak). In conclusion, the SW-HIIE session elicited cardiorespiratory responses that would be classified as vigorous on the intensity scale according to the American College of Sports Medicine’s guidelines for exercise prescription, suggesting that an acute bout of SW-HIIE imposes a great physiological load on the human body