Feeling lazy? Blame it on your nervous system!

Here's one study that could help assuage the guilty feeling associated with laziness. Scientists have discovered that the human nervous system appears wired to expend the least amount of energy and subconsciously might be pushing people to do less rather than more.

The researchers believe their findings, based on laboratory observations of people walking, suggest that the nervous system subconsciously works against the expenditure of energy and seeks to alter movement patterns to use up as little energy as possible.

Their study suggests that people change their walking gait to save even quite small amounts of energy. The findings, published in the journal Current Biology, are consistent with the long-standing observations that people tend to do things through the least effort.

"We have provided a physiological basis for laziness," said Max Donelan, professor of biomedical physiology at the Simon Fraser University in Canada, who led the study.

"We find that even during well-rehearsed movements like walking, the nervous system subconsciously monitors energy used by the body and continuously re-optimises walking patterns with the goal of expending as low energy as possible," he said in a media release.

The researchers planned their study to understand why people walk the way they do, given that there are myriad ways of moving from one point to another. They asked volunteers to walk while wearing a harness-like contraption that discouraged people to walk in their usual styles.

For instance, the contraption has braces near the knees that would hinder certain joint movements. The set-up allowed the scientists to test whether people can sense and change the way they walk in real time to use up less energy.

The experiments found that people can within minutes adapt their step frequency to converge on a new energy expenditure pattern. They do this when the energy saved is even less than five per cent, implying that energy drives our movement patterns.