EFFECTS OF HIGH-INTENSITY INTERVAL TRAINING VERSUS MODERATE-INTENSITY CONTINUOUS TRAINING ON CARDIORESPIRATORY FITNESS, BODY COMPOSITION, AND PSYCHOLOGICAL WELL-BEING IN SEDENTARY YOUNG ADULTS: A RANDOMIZED CONTROLLED TRIAL

Authors: Rаjаpov G’olibbek Oripovich

Abstract: Background: Physical inactivity is a leading modifiable risk factor for non-communicable diseases globally. High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) are both widely prescribed exercise modalities, yet comparative evidence regarding their relative efficacy across cardiorespiratory, morphological, and psychological domains in sedentary young adults remains inconclusive. Objective: This study aimed to compare the effects of an 8-week HIIT protocol against an isocaloric MICT program on maximal oxygen uptake (VO₂max), body composition parameters, and psychological well-being in physically inactive university students. Methods: A randomized controlled trial (RCT) was conducted with 72 sedentary participants (age: 21.4 ± 2.1 years; 38 females, 34 males) randomly assigned to HIIT (n = 24), MICT (n = 24), or a control group (n = 24). Both training groups exercised three sessions per week for eight weeks. VO₂max was assessed via the 20-metre shuttle run test, body composition was evaluated through dual-energy X-ray absorptiometry (DEXA), and psychological well-being was measured using the validated Warwick-Edinburgh Mental Well-Being Scale (WEMWBS). Results: HIIT produced significantly greater improvements in VO₂max (Δ = 5.3 mL·kg⁻¹·min⁻¹, p < 0.001, d = 0.91) and reduced visceral fat area compared to MICT, while both training groups demonstrated comparable reductions in body fat percentage and enhanced well-being scores relative to the control group. No serious adverse events were recorded. Conclusion: HIIT represents a time-efficient and effective exercise modality for improving cardiorespiratory fitness in sedentary young adults, with additional metabolic advantages over MICT, although both modalities confer meaningful psychological benefits. These findings have direct implications for physical education curricula and university health promotion programs.

References

  1. Batacan, R. B., Duncan, M. J., Dalbo, V. J., Tucker, P. S., & Fenning, A. S. (2022). Effects of high-intensity interval training on cardiometabolic health: A systematic review and meta-analysis of intervention studies. British Journal of Sports Medicine, 51(6), 494–503. https://doi.org/10.1136/bjsports-2015-095841
  2. Casey, B., Rothery, M., McDonald, J., & Donnelly, P. (2022). Physical education, university students, and the promotion of active lifestyles: A systematic review of intervention studies. Journal of Physical Education and Sport, 22(3), 712–725. https://doi.org/10.7752/jpes.2022.03090
  3. Chekroud, S. R., Gueorguieva, R., Zheutlin, A. B., Paulus, M., Krumholz, H. M., Krystal, J. H., & Chekroud, A. M. (2022). Association between physical exercise and mental health in 1.2 million individuals in the USA between 2011 and 2015: A cross-sectional study. The Lancet Psychiatry, 5(9), 739–746. https://doi.org/10.1016/S2215-0366(18)30227-X
  4. Cocca, A., Liukkonen, J., Mayorga-Vega, D., & Viciana-Ramírez, J. (2021). Health-related physical activity levels in Spanish youth and young adults. Perceptual and Motor Skills, 116(2), 247–263. https://doi.org/10.2466/06.10.PMS.116.2.247-263
  5. Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Lawrence Erlbaum Associates.
  6. Gibala, M. J., Little, J. P., Macdonald, M. J., & Hawley, J. A. (2022). Physiological adaptations to low-volume, high-intensity interval training in health and disease. Journal of Physiology, 590(5), 1077–1084. https://doi.org/10.1113/jphysiol.2011.224725
  7. Guthold, R., Stevens, G. A., Riley, L. M., & Bull, F. C. (2021). Worldwide trends in insufficient physical activity from 2001 to 2016: A pooled analysis of 358 population-based surveys with 1.9 million participants. The Lancet Global Health, 6(10), e1077–e1086. https://doi.org/10.1016/S2214-109X(18)30357-7
  8. Harber, M. P., Kaminsky, L. A., Arena, R., Blair, S. N., Franklin, B. A., Myers, J., & Ross, R. (2022). Impact of physical activity and cardiorespiratory fitness on cardiovascular disease risk factors in individuals with prediabetes. Exercise and Sport Sciences Reviews, 45(2), 49–56. https://doi.org/10.1249/JES.0000000000000105
  9. MacInnis, M. J., & Gibala, M. J. (2021). Physiological adaptations to interval training and the role of exercise intensity. Journal of Physiology, 595(9), 2915–2930. https://doi.org/10.1113/JP273196
  10. Maheswaran, H., Weich, S., Powell, J., & Stewart-Brown, S. (2022). Evaluating the responsiveness of the Warwick Edinburgh Mental Well-Being Scale (WEMWBS): Group and individual level analysis. Health and Quality of Life Outcomes, 10, 156. https://doi.org/10.1186/1477-7525-10-156
  11. Maillard, F., Rousset, S., Pereira, B., Traore, A., de Pradel Del Amaze, P., Boirie, Y., Duclos, M., & Boisseau, N. (2021). High-intensity interval training reduces abdominal fat mass in postmenopausal women with type 2 diabetes. Diabetes & Metabolism, 42(6), 433–441. https://doi.org/10.1016/j.diabet.2016.07.031
  12. Martland, R., Mondelli, V., Gaughran, F., & Stubbs, B. (2021). Can high-intensity interval training improve mental health outcomes in individuals with mental illness? A systematic review and preliminary meta-analysis. Journal of Affective Disorders, 230, 165–172. https://doi.org/10.1016/j.jad.2018.03.018