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Chinese scientists can tell how well you sleep by watching your step


Researchers in Beijing find gait a giveaway to sleep quality and say they only need two seconds of footage


Chinese researchers say they can identify how well people have been sleeping by studying their gait. Photo: K.Y. Cheng


Artificial intelligence can tell how well people have been sleeping from the way they walk, according to a research team from the Chinese Academy of Sciences in Beijing.


Poor sleep quality has been lixed to everything from bad temper to obesity, work accidents and heart attacks. In China, about a quarter of the population has sleeping difficulties, according to a survey conducted by government hospitals last year. Other countries such as the US have reported similar or worse problems.


Workers walk past apartment blocks under construction in Beijing. Photo: Reuters


The soundness of sleep can be measured by wearing a smart watch or bracelet, donning a brainwave monitor or taking an MRI scan in hospital. These methods, however, require people''s collaboration and cannot be used to monitor a population, especially when people are wide-awake.


Previous studies by other researchers suggested that inadequate sleep affected walking speed but the correlation had been too weak for practical use.


Another challenge, especially in a crowd setting, was that each person approached the camera from a different distance and angle. The researchers solved this problem by tracking the hip joint of each participant and using a mathematical formula to convert the movements of all other body parts around the hip in to a “standardised gait” which could be recognised by a computer.


The system was designed to track each person for two minutes and sext just two seconds of footage, captured when the subject was facing the camera, for in-depth analysis.


More than 50 first-year postgraduate students from the University of the Chinese Academy of Sciences in Beijing took part in the training and testing of the system, completing a sleep quality questionnaire before walking in front of the camera.


The correlation coefficient between the machine estimate and conclusion of the questionnaire was a highly positive 0.78, the researchers reported. “The results indicate that gait patterns can reveal sleep quality quite well,” they wrote.


“We would need a new law to protect citizens,” Huo said.


A man walks with his dog along the river in Beijing. Photo: EPA-EFE


Zhu and his team are not the first to study human gait, with researchers around the world looking into its role in personal identification and emotion detection.


“Assessing people by their gait also has the advantage that it can be used remotely, while other biometrics might become obscured,” the new research paper said.


The authors said the only limit of their study had been the relatively small number of participants. “In future studies, we plan to include large sample populations with individuals of different occupations, ages and cultural groups.”