The comparison between HIIT vs low-intensity exercise on physical fitness and mental health among sedentary females

Abstract

Introduction. Sedentary women face cardiometabolic and mental-health risks, yet direct comparison of high- versus low-intensity exercise on integrated physical and psychological outcomes is sparse. Objective. To compare six weeks of high-intensity interval training (HIIT) with slow jogging in sedentary Malaysian women. Methods. Thirty sedentary females aged 24–34 years were randomised to HIIT (n = 15) or slow jogging (n = 15) and completed supervised 30-minute sessions three times weekly. Outcomes assessed at baseline and postintervention were estimated VO₂ max (20-m shuttle), curl-ups, handgrip strength, sit-and-reach, body composition (InBody 270), Rosenberg Self-Esteem Scale and Quality of Life Scale. Within-group changes were tested with paired t-tests and between-group intervention effects with independent t-tests on change scores. Effect sizes are reported as Cohen's d with 95% confidence intervals. Results. Both groups improved comparably in VO₂ max (HIIT +2.32, slow +2.11 mL·kg⁻¹·min⁻¹), curl-ups (+5.53 vs. +5.20 reps), sit-and-reach (+7.32 vs. +5.73 cm) and self-esteem (+2.94 vs. +1.80; all p > .11). HIIT increased handgrip by 2.23 kg while slow jogging decreased it by 2.60 kg (between-group d = 1.63 [0.80, 2.46], p < .001). HIIT improved all four body-composition outcomes (d = 1.44–2.66, all p < .001); slow jogging increased body fat (+2.44%) and lost skeletal muscle (−0.73 kg). Quality of life rose in HIIT (+8.87) and declined in slow jogging (−6.20); d = 1.53 [0.72, 2.34], p < .001. Conclusion. Both modalities improve cardiorespiratory fitness, muscular endurance, flexibility and self-esteem comparably; HIIT is significantly superior for handgrip, body composition and quality of life, and is the preferred modality for time-efficient, multi-domain improvement in this population.