Acute Cardiorespiratory and Blood Lactate Responses Between Four Different High-Intensity Interval Cycle Exercise Protocols

Abstract

The effects of high-intensity interval training (HIIT) on a cycle ergometer have been observed to elicit health and performance improvements in clinical, sedentary, recreationally-active, and highly-trained populations. However, few studies have compared acute exercise responses between evidence-based HIIT protocols. PURPOSE: To compare cardiorespiratory and blood lactate (BLA) responses between four HIIT cycle protocols from the literature. METHODS: Ten college-age, recreationally-active males and females initially completed an incremental VO2max test in order to prescribe wattage for the HIIT cycle protocols (Table 1). Participants returned on four separate occasions to perform the HIIT sessions in random order. Oxygen consumption (VO2), heart rate (HR), blood lactate (BLA) and rating of perceived exertion (RPE) were measured during each session. Repeated measures ANOVAs (p ≤ 0.05) with post-hoc tests were used to determine significant differences between HIIT cycle protocols for VO2, HR, BLA, and RPE. RESULTS: Several significant differences (p < 0.05) were observed for work, rest, and peak data between protocols (Table 1). CONCLUSION: Protocol A elicited the highest RPE due to the supramaximal work bouts. HR increased rapidly during the 30-s work bouts of Protocol A, which resulted in the highest work and peak HR. The 1-min work bouts for Protocol B elicited greater BLA, peak VO2 and peak HR compared to the 30-sec work intervals for Protocol C despite similar work VO2, work HR, and work to rest ratios (1:1). Protocol D, which was considered HIIT for clinical populations, was not challenging for the recreationally-active population in this study. Future research should examine the responses to longer work intervals at 100% VO2max or intensities greater than 100% VO2max, but less than the supramaximal loads used in Protocol A.Table 1: Descriptive statistics