Walking 4,400 steps a day keeps the doctor away - EJ Insight


Walking 4,400 steps a day keeps the doctor away


Following the unprecedented social disturbances in Hong Kong, many citizens have become restless, making them vulnerable to health problems. To ensure their personal well-being, people need to be on top of their health condition, using various means. Among the useful tools would be smart bracelets that can help monitor the sleep quality.


Many Americans monitor their health condition using smart bracelets. A smart bracelet company had in the recent past announced the collection of 6 billion nights of sleep data. By factoring in the users' gender, age, weight, location and daily activity, we can draw some conclusions about Americans' living style from the anonymous data.


• In general, women sleep an average of 6 hours and 50 minutes per night, 25 minutes more than men, and both groups sleep shorter than the recommended 8 hours. However, women have up to 40 percent more chance of insomnia than men.


• Many elderly people have insomnia. People aged 20 have half an hour more of deep sleep every night than people aged 70.


• Many city dwellers are used to going to bed late on weekends. The Americans go to bed 64 minutes late on weekends, that is, they may go to bed at 11 on weekdays, and after midnight on Saturday and Sunday. They have "social jet lag" – like the time difference experienced in travelling, it is difficult to fall asleep when the biological clock has deviated from the actual time. As a result, they feel sleepy during the day. This is why many people have Monday Blues.


In Hong Kong, there is no record of the number of people who wear smart bracelets during sleep. But it is common to wear a smart device during sports activity. With a built-in pedometer function, it is easy to check one's physical condition after daily exercise.


Earlier, I had mentioned some Western research about nature walks in parks to relieve depression. However, there are different views on the duration required for such activity — some say 15 minutes should be sufficient, while others recommend 45 minutes or so.


What then is the most effective duration? And is there a difference between slow and fast walking?


Since the World Health Organization (WHO) proposed a guideline of "10,000 steps per day" in 2008, it has become a golden rule that is widely quoted. With the iPhone pedometer as the measurement tool, it takes me at least an hour and a half to complete 10,000 steps. I am afraid it is impossible for a full-time working person to met the guideline several times a week.


Recently, I saw some new research that modified the guideline and said that 4,000 steps every time is good enough to improve the health condition.


In a study, researchers from the Harvard Medical School in the United States targeted 16,741 old women aged 72 on average. For the study, the women had to wear an accelerometer during waking hours for 7 days. The study found that people who walked about 4,400 steps per day had a significantly lower mortality rate than those who walked only 2,700 steps. If they could reach 7,500 steps per day, mortality rates would significantly be decreased.


The study tracked the respondents for more than four years (2011-2015). During the period, 504 women died, and over half of them were in the group of 2,700 steps per day.


The average person's pace is about 100 steps per minute, and walking 4,400 steps is like walking for 44 minutes. If we count the steps of commuting to and from office and going out for lunch, it almost meets the standard.


Apart from at least 4,400 steps a day, what is the optimal walking speed? In another research, the University of Leicester in the United Kingdom collected data from more than 470,000 people within seven years. The study indicated that brisk walking is more beneficial to all people. Those engaged in such activity would live 10 years longer than those who are leisure walkers.


According to the standard of the US Centers for Disease Control and Prevention, "brisk pace" means at least 3.5 miles per hour, which is about the speed at which you can talk but not sing while walking.


The Hong Kong government is actively promoting the "Walk in Hong Kong" initiative to enhance the overall walkability and encourage the public to lead a healthy life. The initiative can help improve people's physical condition and help relieve depression. Let's get moving now!



Dr. Winnie Tang
Adjunct Professor, Department of Computer Science, Faculty of Engineering and Faculty of Architecture, The University of Hong Kong