Walking and the way we control our pace (known as gait) can be affected by the lack of sleep, according to a new study by researchers at MIT and the University of Sao Paulo. But no worries, there’s a simple and effective solution to reduce this clumsiness: just make up for the lost sleep, even if it’s just a few hours on the weekend.
There’s a lot of evidence out there linking our length and quality of sleep to our performance in activities that are mentally taxing, such as maintaining a conversation or solving problems. But researchers haven’t looked that closely yet on how sleep influences activities that are less cognitively demanding, such as walking.
Now, in a new study, researchers carried out a set of experiments with student volunteers and found that those who got limited sleep didn’t have much control when walking on a treadmill test. This was even more clear on students who didn’t sleep at all so to get ready for an exam the following morning, with their gait control decreasing further.
“Scientifically, it wasn’t clear that almost automatic activities like walking would be influenced by lack of sleep,” Hermano Krebs, co-author, said in a statement. “We also find that compensating for sleep could be an important strategy. For instance, for those who are chronically sleep-deprived, like shift workers, clinicians, and some military personnel.”
Sleep and walking
Over the last decade, Krebs and his colleagues at MIT have looked at gait control and the mechanics of walking, trying to develop strategies for patients who had suffered strokes and other conditions that limited their mobility. He has shown that walking actually involves some conscious influence, adding to the more automatic processes.
In 2013, MIT signed a partnership with the University of Sao Paulo to find out whether more subtle stimuli like auditory cues could also influence walking. They did experiments in which they ask volunteers to walk on a treadmill while playing and shifting the frequency of a metronome. The volunteers matched their walk to the beat without realizing it.
This suggested that gait wasn’t just an automatic process and that there was a lot of influence from the brain, Krebs explains. Experiments then continued, focusing on students from Brazil. The researchers noticed that students tended to perform worse on the experiments when being sleep-deprived, so they decided to embrace this situation.
In their new study, the researchers enlisted a group of volunteers to participate in an experiment on the effects of the lack of sleep on gait control. Students were given a watch to monitor their activity over 14 days, which in turn gave information to the researchers on how many hours were the students sleeping and how many hours were they active. No instruction was given on how much to sleep.
Students slept on average six hours per day, with some compensating with more hours during the weekend. Right before the study was about to finish, one group of students stayed awake all night in the laboratory. They were designated the Sleep Acute Deprivation Group and were asked to carry out a walking test on a treadmill placed in the laboratory.
Students had to keep step with the beat of a metronome, as researchers raised and lowered the speed without letting the participants know. There were cameras in place that captured how the students walked, especially the moment in which their heel hit the treadmill compared to the beat of the metronome. Many were off the rhythm and missed plenty of beeps, indicating that staying awake is taxing even on simple activities such as walking.
“The results show that gait is not an automatic process, and that it can be affected by sleep deprivation,” Krebs said. “They also suggest strategies for mitigating effects of sleep deprivation. Ideally, everyone should sleep eight hours a night. But if we can’t, then we should compensate as much and as regularly as possible.”