The sub-acute effects of high-intensity interval training in healthy young adults: respiratory parameters, aerobic capacity and perceived stress.

Background: Although the effects of sub-maximal continuous aerobic training (SCT) and high-intensity interval training (HIIT) are well studied in performance athletes and in several patient groups, there is not much evidence about the effects of these exercises in sedentary healthy young population. The aim of the study was to compare the effects of these two different types of aerobic exercises on respiratory parameters, aerobic capacity and perceived stress in healthy university students.

Methods: Thirty-six healthy, young subjects with a mean age of 20.83±0.97 years were included in the study (N.=19 in HIIT and N.=17 in SCT). Pulmonary function tests (PFTs) and respiratory muscle strength (RMS) assessments were done using a desktop spirometer. Aerobic capacity was estimated with the Bruce treadmill exercise test. The Perceived Stress Scale (PSS) was used for the assessment of stress perception. All participants exercised 3 times per week for 4 weeks (a total of 12 sessions).

Results: After 12 sessions, the peak expiratory flow parameter (a PFT value) of both groups showed significant increases, but there was no difference between the groups. The RMS of the subjects increased significantly in both the groups (P<0.05), but there was no significant difference between the groups. Both groups showed significant increases in terms of aerobic capacity (P>0.05), and the improvement was significantly higher in the HIIT group. Perceived stress values showed a significant increase in the SCT group.

Conclusions: Based on the results of this study, the two exercise types were found to have similar effects on RMS. Also, when compared with SCT, HIIT was found to have more effect on aerobic capacity.