Researchers from the exercise science and communication sciences and disorders departments in the University of South Carolina Arnold School of Public Health have completed a study on the effect of energy-matched exercise intensity on brain-derived neurotrophic factor and motor learning. The paper was published in Neurobiology of Learning and Memory.
Previous research suggests that pairing high-intensity exercise with motor task practice can enhance motor learning beyond task practice alone. This enhancement is thought, in part, to be facilitated by an exercise-related increase in the protein, brain-derived neurotrophic factor (BDNF).
This study examined the effect of different exercise intensities on BDNF levels and motor learning while controlling for exercise-related energy expenditure. Participants included 48 young, healthy adults who were assigned to one of three groups: high-intensity exercise, low-intensity exercise, or quiet rest.
Each participant expended 200 kcals regardless of intensity or duration of the exercise bouts.
BDNF was measured before and after exercise or rest. After exercise or rest, all participants practiced a three-dimensional motor learning task, which involved reach movements made to sequentially presented targets, and retention was tested after 24 hours. BDNF genotype was determined for each participant to explore its effects on BDNF and motor learning.
The authors found that all participants equally improved performance. This improvement was indicated by a reduction in time to complete the task. However, the kinematic profile used to control the reach movement differed by group. The quiet rest group traveled the shortest distance between the targets, the high-intensity group had higher reach speed (peak velocity), and the low-intensity group had earlier peak velocities.
The rise in BDNF post-exercise was not significant, regardless of exercise intensity, and the change in BDNF was not associated with motor learning. The BDNF response to exercise did not differ by genotype. However, performance differed between those with the polymorphism (Met carriers) and those without (Val/Val). Compared to the Val/Val genotype, Met carriers had faster response times throughout task practice, which was supported by higher reach speeds and earlier peak velocities.
The researchers concluded that while exercise (both low- and high-intensity) can alter the kinematic approach used to complete a reach task, these changes appear unrelated to a change in BDNF. In addition, the BDNF genotype did not influence BDNF concentration, but it did have an effect on motor performance of a sequential target reach task.