Summary: Does a 15-minute run benefit an athlete more than a beginner? New research from UCL shows the answer is yes. The study demonstrates that as aerobic fitness improves, the brain becomes better at releasing brain-derived neurotrophic factor (BDNF) — a key protein that supports neuron growth, strengthens synapses, and helps regulate executive functions such as attention and inhibition.
While any person can gain cognitive benefits from exercise, people who completed a 12-week training program experienced substantially larger post-exercise increases in BDNF and improved prefrontal cortex activity after a single bout of exercise. In short, improving your fitness enhances your brain’s ability to extract greater benefit from every subsequent workout.
Key Facts
- The 15-minute trigger: A single 15-minute session of moderate-to-vigorous aerobic exercise is sufficient to stimulate BDNF release.
- Fitness amplifies the effect: Individuals with higher aerobic fitness show a much larger surge in BDNF following intense exercise than unfit individuals.
- Rapid gains: Inactive people began to show improved brain responses to exercise after as little as six weeks of consistent training.
- Executive function improvement: Post-exercise increases in BDNF were linked to better performance on attention and inhibition tasks governed by the prefrontal cortex.
- VO2 max connection: The magnitude of the BDNF response correlated with improvements in VO2 max, underlining the link between aerobic fitness and brain health.
Source: UCL
Overview of the study
Published in Brain Research and led by Dr Flaminia Ronca (UCL Surgery & Interventional Science and the Institute of Sport, Exercise and Health), the study followed inactive adults through a 12-week cycling program (three sessions per week). The goal was to measure how improvements in aerobic fitness changed the brain’s biochemical and functional response to exercise.
Thirty participants (23 male, 7 female) entered the 12-week intervention. Fitness was tracked with VO2 max tests every six weeks. BDNF levels were measured before and after VO2 max testing. Researchers also administered cognitive tests focused on executive functions and memory while recording prefrontal cortex activity using functional near-infrared spectroscopy (fNIRS).
By the end of the program, baseline (resting) BDNF levels had not changed significantly. However, participants produced a larger spike in BDNF following intense exercise than they did before training. That amplified response was correlated with improvements in VO2 max. Greater BDNF increases and higher overall BDNF measures were associated with altered activity in frontopolar, dorsolateral and orbitofrontal regions of the prefrontal cortex during attention and inhibition tasks, but not during the memory task.
Lead author Dr Flaminia Ronca commented that although exercise’s benefits to the brain are well known, this study shows the brain’s responsiveness to a single session of exercise improves as fitness increases — and meaningful changes can occur in just six weeks.
Key Questions Answered
A: Yes. Fifteen minutes of moderate-to-vigorous exercise is enough to trigger BDNF release. Over time, as you become fitter, that same 15-minute session yields increasingly larger BDNF responses — effectively training your brain to respond more strongly to exercise.
A: BDNF (brain-derived neurotrophic factor) supports the growth and survival of neurons, strengthens synaptic connections, and supports neural plasticity. This study finds fitter individuals produce more BDNF in response to acute exercise.
A: The study linked exercise-induced BDNF boosts primarily with improvements in executive functions — attention and decision-making — rather than direct memory performance. A short cardio session can therefore be especially helpful before tasks that require sustained focus and inhibitory control.
Editorial Notes
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full for accuracy.
- Additional context was added by editorial staff.
About this exercise and neuroscience research news
Author: Tom Cramp
Source: UCL
Contact: Tom Cramp – UCL
Image: Image credited to Neuroscience News
Original Research: Open access. “BDNF relates to prefrontal cortex activity in the context of physical exercise” by Flaminia Ronca, Cian Xu, Ellen Kong, Dennis Chan, Antonia Hamilton, Giampietro Schiavo, Ilias Tachtsidis, Paola Pinti, Benjamin Tari, Tom Gurney, and Paul W. Burgess. Brain Research. DOI: 10.1016/j.brainres.2026.150253
Abstract
BDNF relates to prefrontal cortex activity in the context of physical exercise
Exercise supports brain health and cognitive function and elevates brain-derived neurotrophic factor (BDNF). BDNF improves brain metabolism, vascular function, neurotransmission and synaptic plasticity, but how exercise-induced BDNF changes relate to cognitive improvements remains unclear. This study examined the relationship between changes in plasma and serum BDNF and haemodynamic indicators of prefrontal cortex function in sedentary adults.
Participants were randomized into a 12-week cycling intervention group and a no-intervention control group. VO2 max tests tracked fitness changes. Blood samples measured plasma and serum BDNF before and after exercise testing. Executive function and memory tasks were completed while prefrontal cortex activity was recorded with fNIRS. The correlation-based signal improvement (CBSI) method assessed haemodynamic changes.
Results showed no increase in resting-state BDNF at the end of the intervention, but a significant exercise-induced increase in serum BDNF after 12 weeks correlated with VO2 max improvements. Higher plasma BDNF and exercise-induced serum BDNF were linked to reduced CBSI values in frontopolar, dorsolateral and orbitofrontal prefrontal regions during attention and inhibition tasks, but not during a memory task. These findings indicate that improving physical fitness enhances BDNF transcription in response to acute exercise, which may help modulate neural function during executive tasks after exercise.