This pilot study, conducted in advance of a future definitive randomized controlled trial, aimed to investigate the feasibility of using a HIIT-based intervention to induce neurophysiological stress responses that could be associated with possible changes in mood. Twenty-five active male college students with an average age of 21.7 ± 2.1 years, weight 72.6 ± 8.4 kg, height 177 ± 6.1 cm, and BMI: 23.1 ± 1.4 kg/m2 took part in this quasi-experimental pilot study in which they were evaluated in two different sessions. In the first session, subjects performed a graded exercise test to determine the cycling power output corresponding to VO2peak. The second session consisted of (a) pre-intervention assessment (collection of blood samples for measuring plasma corticotropin and cortisol levels, and application of POMS questionnaire to evaluate mood states); (b) exercise intervention (10 × 1-min of cycling at VO2peak power output); (c) post-intervention assessment, and (d) 30-min post-intervention evaluation. Significant post-exercise increases in corticotropin and cortisol plasma levels were observed whereas mood states decreased significantly at this assessment time-point. However, a significant increase in mood was found 30-min after exercise. Finally, significant relationships between increases in stress hormones concentrations and changes in mood states after intense exercise were observed. In conclusion, our HIIT-based intervention was feasible to deliver and acceptable to participants. A single bout of HIIT induced acute changes in mood states that seems to be associated with hypothalamic-pituitary-adrenal axis activation.
Keywords: HIIT; corticotropin; cortisol; exercise; mood states; stress.