Purpose: This study compared physiological and perceptual variables between short and long durations of rowing-based high intensity interval exercise (HIIE). Methods: Fourteen active adults (age = 26.4 +/- 7.2 yr) performed incremental rowing exercise to fatigue to measure maximal oxygen uptake (VO(2)max) and peak power output (PPO). The subsequent 20 min sessions required HIIE (eight 60 s efforts at 85%PPO with 90 s of active recovery at 20%PPO or 24 20 s efforts at 85%PPO with 30 s of active recovery at 20%PPO) or moderate intensity continuous exercise (MICE) at 40%PPO. During exercise, VO2, heart rate (HR), blood lactate concentration (BLa), rating of perceived exertion (RPE), and affective valence were measured. Results: Data show significantly (p < 0.001) higher peak VO2 (84 +/- 7 vs. 76 +/- 5%VO(2)peak, d = 0.99), peak HR (94 +/- 4%HRpeak vs. 90 +/- 4%HRpeak, d = 1.12), BLa (7.0 +/- 2.5 mM vs. 4.1 +/- 1.0 mM, d = 1.22), end-exercise RPE (12.8 +/- 2.0 vs. 11.0 +/- 1.7, d = 1.29), and lower affective valence (2.1 +/- 1.6 vs. 2.9 +/- 1.2, d = 0.61) with long versus short HIIE. Time spent above 85%HRpeak was significantly higher (p < 0.001) in short versus long HIIE (606 +/- 259 vs. 448 +/- 26 s, d = 0.91). Conclusion: Longer rowing-based intervals elicit greater cardiometabolic and perceptual strain versus shorter efforts, making the latter preferable to optimize perceptual responses to HIIE.