Effects of High-Intensity Interval Training on Executive Functions and IGF-1 Levels in Sedentary Young Women: A Randomized Controlled Trial

Manuel Jesús Jiménez Roldán^1,2*Luis Carrasco¹Borja Sañudo Corrales¹

• ¹Faculty of Education Sciences, University of Seville, Seville, Spain
• ²University School 'Francisco Maldonado', University of Seville, Seville, Spain

Purpose: Sedentary behavior among university students negatively affects physical and neurocognitive health, including executive functions and insulin-like growth factor 1 (IGF-1) levels. Physical activity can increase IGF-1 and improve cognitive performance, but the combined effect of high-intensity interval training (HIIT) and increased physical activity on these outcomes is not well understood. This study examined the chronic effects of a 12-week HIIT program, with or without added daily physical activity, on executive functions and IGF-1 concentrations in sedentary female university students, including a 12-week follow-up period.Method: In this randomized controlled trial, 77 sedentary female students were assigned to three groups: HIIT (n=25), HIIT plus increased physical activity (HIIT+PA, n=25), and control (CG, n=27). Assessments were conducted at baseline (T1), post-intervention (T2), and follow-up (T3). Salivary IGF-1 was measured via ELISA. Executive functions were assessed using the Stroop Test, Wisconsin Card Sorting Test (WCST), and Digit Span Test (DST). HIIT sessions lasted 40 minutes, three times per week, and were delivered online. The HIIT+PA group also aimed to complete 10,000 steps daily.Results: No significant changes in IGF-1 levels were found over time or between groups, though both HIIT groups showed upward trends at follow-up. Improvements were observed in cognitive flexibility (WCST) and working memory (DST-B, DST-T) over time, but without significant group × time interactions. Only WCST-E-P showed a significant group effect (p = 0.028), suggesting differences in cognitive rigidity. The HIIT+PA group showed a non-significant trend toward improved inhibitory control (Stroop accuracy), and working memory improved significantly over time, particularly in the HIIT group.Conclusion: A 12-week HIIT program, with or without additional physical activity, may enhance executive functions—especially working memory and cognitive flexibility—in sedentary young women. However, these benefits were not exclusive to intervention groups, indicating possible test-related or external influences. While IGF-1 levels trended upward, no significant effects were confirmed. These results suggest HIIT may support cognitive health, but further research is needed to explore underlying mechanisms and long-term effects.