Some people may find it harder to do physical exercise or activity than others. A study has shown that dopamine levels may have a say in this.
Dopamine: the Brain's Reward Center
According to the Cleveland Clinic, dopamine is one of the brain-produced neurotransmitters that takes on the role of the brain's reward center; it stated it is linked to pleasure. High or low dopamine levels are linked to various conditions, such as Parkinson's disease, ADHD (attention deficit hyperactivity disorder), and restless legs syndrome.
Aside from being linked to reward-seeking, motivation, and pleasure, dopamine has now been observed to explain why physical activity and exercise may feel difficult for some but easy for others.
Dopamine Levels Affect How Difficult Physical Exercise Feels
The study, led by a team from Johns Hopkins Medicine, covered patients with Parkinson's disease. It was published in the Parkinson's Disease Journal.
According to the researchers, these findings could lead to a deeper understanding of Parkinson's disease, new fatigue treatments linked with depression and other conditions, and more effective methods of establishing and sticking to fitness regimens.
Science Daily reports that Vikram Chib, Ph.D., an associate professor from Johns Hopkins University School of Medicine's Department of Biomedical Engineering and a research scientist from the Kennedy Krieger Institute, says that researchers have been trying to know why making physical efforts is easier for some compared to others. The study's findings show that dopamine levels in the brain could be a vital factor.
Professor Chib notes that after going through physical activities, people's perceptions and self-reports regarding their efforts vary. This also affects how they decide to undertake future physical exertions.
As per Science Daily, prior studies have shown that those with higher dopamine levels are more willing to exert physical activity for the rewards that come with it. However, this study focuses on the role of dopamine when it comes to a person's self-assessment regarding the physical effort required to finish a task. This is without a promised reward.
As part of the study, the researchers recruited 19 adults who had Parkinson's disease, which is a brain condition linked to depleted dopamine levels that leads to uncontrollable and unintended movements.
In a laboratory setting, nine female volunteers and ten male volunteers, whose average ages were 67, were asked to perform a physical task on two varying days within four weeks of each other. This task was to squeeze a hand grip that had a sensor.
In one day, the patients were tasked with taking their daily dopamine medication. On the other hand, they were asked not to take their medication for over 12 hours before the squeezing task.
When they took their dopamine medication, the participants had more accurate self-assessments of their efforts compared to when they did not take the medication. There was also less effort variability, revealing accurate squeezes when asked to squeeze at varying effort levels.
On the contrary, their efforts were overreported when they did not take the medication. This meant that the task appeared physically harder. They also had higher grip variability after the cues.
The researchers also conducted a second and third experiments. The second one revealed that when the participants took medication, they had a higher willingness to take chances with performing more physically effortful tasks compared to when they did not take their medication. The third experiment, on the other hand, suggests that dopamine's influence on risk-taking preferences is linked to decision-making based on physical effort.
Altogether, the findings show how dopamine plays a role in assessing how physically effortful a task is. This may, in turn, affect their willingness to exert more effort in future physical studies.
Knowing more about the biology and chemistry of motivation can help devise ways to motivate more people to undergo and stick with their physical therapy and exercise regimens. Moreover, inefficient dopamine signaling may also shed light on the fatigue experienced by those with depression or long COVID.
At present, researchers are looking into how dopamine impacts clinical fatigue.
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