Effects of psychophysiological stress on perceptual responses during low-volume high intensity interval exercise: insights from ACTH and cortisol in overweight-to-obese adults.

Background: Low-volume high-intensity interval exercise (Lv-HIIE) is a time-efficient training strategy, but little is known about how psychophysiological stress, as reflected by endocrine markers, is associated with perceived exercise experiences in overweight-to-obese adults. More specifically, research on ACTH- and cortisol-related stress responses during multi-week Lv-HIIE is very limited, and no existing studies have examined how these hormonal patterns are related to perceptual outcomes. Purpose: This study examined the associations of ACTH and cortisol responses with perceptual outcomes during a 10-week Lv-HIIE intervention and whether these associations changed across repeated sessions. Methods: Thirty-two inactive adults (11 males, 21 females; 28.3 ± 4.9 years) with overweight or obesity completed 30 Lv-HIIE sessions over 10 weeks, HIIE consisted of 8 × 1-min work intervals performed at 90% of maximal aerobic speed (MAS), separated with 75-s recovery periods. Perceptual responses (affective valence, arousal, perceived exertion, perceived recovery, and enjoyment) and stress markers (ACTH, cortisol) were collected at sessions 1, 15, and 30. Heart-rate responses and body-composition measures were also assessed. Results: Lv-HIIE produced small but significant improvements in body composition and aerobic fitness (%BF, WHR, V̇O Conclusion: Endocrine stress markers (ACTH and cortisol) were significantly associated with perceptual responses during the 10-week Lv-HIIE, with the strength of their correlations changing across the exercise period. These findings suggest that Lv-HIIE may promote improved perceptual tolerance and affective adaptation during training in adults with excess body weight.