Humans wired to use fewer calories while walking, study shows

Relief in the form of a new study! Your tendency to take it easy — whether that means moving slowly, or not at all — is biological.

According to a recent study conducted at the Simon Fraser University in Canada, our nervous system is adept in changing our behavior to expend the least amount of energy possible. ‘We found that people readily change the way they walk – including characteristics of their gait that have been established with millions of steps over the course of their lifetime – to save quite small amounts of energy,’ explained lead researcher Max Donelan.

‘Even within a well-rehearsed movement like walking, the nervous system subconsciously monitors energy use and continuously re-optimises movement patterns in a constant quest to move as cheaply as possible,’ Bonelan informed.

To reach this conclusion, the researchers asked people to walk while they wore a robotic exoskeleton. This contraption allowed the researchers to discourage people from walking in their usual way by making it more costly to walk normally than to walk some other way. More specifically, the researchers made it more difficult for participants to swing their legs by putting resistance on the knee during normal walking, whereas the researchers eased this resistance for other ways of walking.

This allowed the researchers to test whether people can sense and optimise the cost associated with their movements in real time. The experiment revealed that people adapt their step frequency to converge on a new energetic optimum very quickly – within minutes. What’s more, people do this even when the energy savings is quite small: less than 5 percent. There is a bright side to this. ‘Sensing and optimising energy use that quickly and accurately is an impressive feat on the part of the nervous system. You have to be smart to be that lazy!’ noted lead author Jessica Selinger. The findings, which were made by studying the energetic costs of walking, apply to most of our movements. The paper appeared in the Cell Press journal Current Biology.

Agencies/Canadajournal