Purpose: To compare psychological responses to, and preferences for, moderate-intensity continuous training (MICT), high-intensity interval training (HIIT), and sprint interval training (SIT) among inactive adults; and to investigate the relationships between affect, enjoyment, exercise preferences, and subsequent exercise behavior over a 4-wk follow-up period. Methods: Thirty inactive men and women (21.23 ± 3.81 yr), inexperienced with HIIT or SIT, completed three trials of cycle ergometer exercise in random order on separate days: MICT (45 min continuous; approximately 70% to 75% of HR maximum (HRmax)); HIIT (10 × 1 min bouts at approximately 85% to 90% HRmax with 1-min recovery periods); and SIT (3 × 20-s “all-out” sprints with 2-min recovery periods). Perceived exertion (RPE), affect, and arousal were measured throughout the trials and enjoyment was measured postexercise. Participants rank-ordered the protocols (1–3) according to preference and logged their exercise over a 4-wk follow-up. Results: Despite elevated HR, RPE, and arousal during work periods (P ’s < 0.05), and negative affect during HIIT and SIT, enjoyment and preferences for MICT, HIIT, and SIT were similar (P’ s > 0.05). In-task affect was predictive of postexercise enjoyment for each type of exercise (r’ s = 0.32 to 0.47; P’ s < 0.05). In-task affect and postexercise enjoyment predicted preferences for HIIT and SIT (r s’s = −0.34 to −0.61; P’ s < 0.05), but not for MICT (P’ s > 0.05), respectively. Over the follow-up, participants completed more MICT (M = 6.11 ± 4.12) than SIT sessions (M = 1.39 ± 1.85; P < 0.01, d = 1.34). Although participants tended to complete more sessions of MICT than HIIT (M = 3.54 ± 4.23; P = 0.16, d = 0.56), and more sessions of HIIT than SIT (P = 0.07, d = 0.60), differences were not significant. In-task affect predicted the number of sessions of MICT (r = 0.40; P < 0.05), but not HIIT or SIT (P’ s > 0.05). Conclusions: This study provides new evidence that a single session of HIIT and SIT can be as enjoyable and preferable as MICT among inactive individuals and that there may be differences in the exercise affect–behavior relationship between interval and continuous exercise. [ABSTRACT FROM AUTHOR]