Our bodies adapt to expend little energy

By RAYYAN JOKHAI

Researchers have come across an astonishing observation that may discourage or at the very least concern those of you who spend hours at the recreational center trying to burn as many calories as physically possible.

Jessica C. Selinger, Shawn M. O’Connor, Jeremy D. Wong and J. Maxwell Donelan have observed that our own nervous systems are actually working against us as we incessantly push ourselves to exercise.

It’s been known quite some time that, given options, people choose to move in an energetically optimal path. In fact, this idea is ingrained in the science of movement and is simply observed in how most people would rather walk the shortest path between ‘Point A’ and ‘Point B,’ would rather sit than stand and would rather drive than jog.

However, the way in which people are able to adapt their movements to best suit the energy efficient method of action has been a mystery. While many hypotheses have been offered as answers to this puzzling question, none have used the nervous system as a central point in their argument, meaning that the system’s objective of energy minimization has been largely unaddressed.

The study performed by these four researchers suggests that at a subconscious level our nervous systems are constantly adapting the way in which we move so that we expend the least amount of energy possible at all times. In doing so when we are at the gym, without us being aware, our nervous system is keeping the amount of calories we burn to a minimum by changing how we are moving when we exercise in order to conserve the most amount of energy. Regardless of how active we are, there may be no getting away from our instinctive lethargy.

The experimental design allowed the researchers to test whether or not people would be able to recognize the change in gait environment and subsequently adapt to this new environment and achieve new optima.

“We think of our experiment like dropping someone into a new world with all new rules. Any walking strategies that may have developed over evolutionary or developmental timescales are now obsolete in this new world,” Selinger said in a press release.

The researchers used robotic exoskeletons to create varying gait situations to see how subjects would alter their movement to achieve a new efficient method of walking. Step frequency specifically was the variable manipulated since it is such a fundamental characteristic of walking and is a major factor in gait optimization. The robotic exoskeletons were used to act against the knee joints providing resistance against the walking motion of the subjects.

While the minimal time it took for subjects to alter their step frequency to achieve new optima is incredible, what’s even more bewildering is that the subjects did so even when the energy saved was below five percent. In conducting this experiment, the researchers were able to conclude that energetic costs shape our movements at a subconscious neurological level.

Despite having walked for as long as physically possible, subjects readily adapted to keep energy disbursement at a physiological minimum. The way we walk, while seemingly immutable to us, is in fact quite supple.

The researchers don’t plan to stop at this conclusion and intend to delve into the question of how our bodies are able to ultimately choose which method conserves maximum energy.