Acute Neurochemical and Cognitive Changes After HIIT vs MICT/LICT

This study examines whether the intensity of a single running session changes a blood marker related to brain health (brain-derived neurotrophic factor, BDNF), blood lactate, and performance on a short thinking task that measures attention and self-control (the Stroop test) in healthy young adult men. Twelve healthy males (18-25 years) will complete four separate sessions in a randomized, counterbalanced order, with at least 7 days between sessions. Each session includes an 8-minute warm-up followed by 24 minutes of one of the following conditions: low-intensity continuous running, moderate-intensity continuous running, high-intensity interval running (repeated 15-second fast runs with 15-second passive rest, organized into sets), or a seated rest control session. Running pace will be individualized based on a prior fitness test. A small venous blood sample (about 8 mL) will be collected immediately before and within 1 minute after each session. After each session, participants will complete the Stroop test. The main outcomes are the before-to-after changes in serum BDNF, blood lactate, and Stroop test performance across the four conditions.