Dopamine release explains why exercise boosts your brain

An international team of researchers has explored the mechanisms behind why cognitive performance improves in response to exercise — and they’ve found that dopamine plays a key role.

The neurotransmitter and hormone — which is tied to pleasure, satisfaction and motivation — is already known to increase when you work out, but the new study suggests it is also linked to faster reaction time during exercise. The researchers say it could lead to a new therapeutic pathway for cognitive health, because of dopamine’s significant role in conditions including Parkinson’s disease, schizophrenia, ADHD, addiction and depression.

The researchers measured the release of dopamine in the brain using a PET scanner, which tracks the metabolic and biochemical activity of the cells in the body. When a participant cycled lying down in the machine, their brain increased the amount of dopamine released, and this process was linked with improved reaction time.

“We know cardiovascular exercise improves cognitive performance, but the exact mechanisms behind this process have not been rigorously investigated in humans until now,” said Dr Joe Costello, from the University of Portsmouth.

“Using novel brain imaging techniques, we were able to examine the role dopamine plays in boosting brain function during exercise, and the results are really promising. Our current study suggests the hormone is an important neuromodulator for improved reaction time ... [supporting] growing evidence that exercise prescription is a viable therapy for a host of health conditions.”

Three experiments were carried out with a total of 52 male participants. In the first, individuals were asked to carry out cognitive tasks at rest and while cycling in the PET scanner, so the team could monitor the movement of dopamine in their brain. The second used electrical muscle stimulation to test whether forced muscle movement to stimulate exercise would also improve cognitive performance. The final experiment combined both voluntary and involuntary exercise.

In the experiments where voluntary exercise was carried out, cognitive performance improved. This was not the case when only forced electrical stimulation was used.

“We wanted to remove voluntary muscle movement for part of the study, to see if the process in which acute exercise improves cognitive performance is present during manufactured exercise — but our results indicate that the exercise has to be from the central signals of the brain, and not just the muscle itself,” said Associate Professor Soichi Ando, from The University of Electro-Communications in Japan.

“This suggests that when we tell our central command to move our body during a workout, that’s the process which helps the dopamine release in the brain.”

The team’s previous study tested the theory that the more oxygen we breathe during a workout, the more awake our brain is — and found no change to an individual’s reaction time when cycling both inside and outside of an environment with low levels of oxygen (hypoxia). According to Costello, “These latest findings support our previous theory that cognitive performance during exercise is affected by changes to brain-regulating hormones, including dopamine.”

The research paper, published in The Journal of Physiology, says further studies are needed to fully understand how dopamine release is linked to cognitive performance following exercise. The authors recommend that more participants are needed in future experiments, from a range of populations including women and older individuals, over a longer period of time.