Human brains are naturally attracted to laziness: Study

If getting off the couch for a workout feels like a battle of willpower, there may be a biological reason behind it. Researchers have found that the human brain may be naturally drawn towards sedentary behaviour, making physical activity require greater mental effort.

The study, led by researchers from the University of British Columbia (UBC) in Canada, suggests that although people can consciously choose to be active, the brain may instinctively find relaxation and inactivity more appealing.

The findings were published in the journal Neuropsychologia.

For the study, researchers recruited young adults and asked them to sit in front of a computer while controlling an on-screen avatar. Images representing physical activity and inactivity were displayed one at a time.

Participants were instructed to move the avatar as quickly as possible towards images showing physical activity and away from those depicting inactivity. They were then asked to perform the opposite task.

At the same time, electrodes were used to record the participants' brain activity.

The researchers found that participants were generally quicker at moving towards images associated with physical activity and away from sedentary activities. However, brain activity measurements revealed an important difference: moving away from inactivity required greater involvement of brain resources.

“This faster avoidance of physical inactivity comes at a cost -- and that is an increased involvement of brain resources,” said Matthieu Boisgontier, a postdoctoral researcher at UBC.

According to the researchers, the findings suggest that the brain may have an inherent tendency to conserve energy and favour less physically demanding behaviour. This could help explain why people may know that exercise is beneficial but still find it difficult to make physical activity a regular habit.

The researchers believe this tendency may have an evolutionary explanation. For much of human history, conserving energy could have been advantageous when food and physical resources were uncertain. Modern lifestyles, however, have dramatically reduced the need for regular physical exertion while making sedentary activities increasingly accessible.

Boisgontier suggested that this underlying brain response could also help explain why public health campaigns have struggled to reverse the growing problem of physical inactivity.

The study does not mean that people are biologically destined to be lazy or incapable of exercising. Rather, it indicates that choosing an active lifestyle may sometimes require consciously overriding an automatic preference for inactivity.

An important question now is whether the brain can be trained to respond differently.

Boisgontier said that automatic behaviours can be difficult to suppress precisely because people are often unaware of them. However, recognising that such an automatic response exists could be an important first step towards changing it.

The findings add another dimension to the challenge of encouraging people to exercise, suggesting that tackling physical inactivity may require not only motivation and better opportunities for exercise, but also an understanding of how the brain naturally responds to movement and rest.