How a two-minute walk every hour could save your life
Spending too long on your backside has been linked to heart disease, diabetes and premature death. The good news is, it takes just a modicum of effort to offset these health hazards.
Adding only two minutes of walking each hour to your daily routine just might do the trick, says a study published last week in the Clinical Journal of the American Society of Nephrology.
This works out to an extra 400 calories expended each week for the average adult, assuming they are awake for 16 hours a day.
Researchers from the University of Utah School of Medicine thought it would be unrealistic to expect people to replace sitting with more exercise, considering that 80 per cent of Americans fall short of completing the World Health Organisation recommended 150 minutes of moderate-intensity physical activity each week.
Hongkongers aren't much better: only about one-third meet the recommendations, according to 2014 statistics from the Centre for Health Protection.
With this mind, the scientists investigated the health benefits of a more achievable goal: trading sitting for light activities, such as casual walking, light gardening or cleaning for short periods of time.
They analysed data from 3,243 participants of the US National Health and Nutrition Examination Survey, who wore accelerometers that objectively measured the intensity of their activities. The participants were then tracked for three years after the data was collected. During the period, 137 of them died.
The researchers found no benefit to decreasing sitting time by two minutes each hour, or adding a corresponding two minutes more of low-intensity activities such as standing.
However, replacing sitting with low-intensity activities for two minutes per hour reduced the risk of death by 33 per cent.
Previous studies have also shown that at least some activity is better than none. For example, experts writing in the British Medical Journal argue that the 150-minute target is beyond the reach of some people, especially the elderly.
Dr Philippe de Souto Barreto at the University Hospital of Toulouse in France suggests that health policies and actions should promote the benefits of small increases in daily physical activity rather than just focusing on meeting recommendations.
In addition, a study of more than 250,000 US adults aged 50 to 71 found that adding less than an hour of moderate physical activity a week helped to reduce the risk of all causes of death by 15 per cent, and that doing 20 minutes or more of vigorous physical activity even just once a week reduced the causes of death by 23 per cent.
"Exercise is great, but the reality is that the practical amount of vigorous exercise that can be achieved is limited," says Professor Tom Greene, the senior author of the University of Utah study and director of the Study Design and Biostatistics Centre.
Another author of the study and Utah professor of medicine Srinivasan Beddhu says: "To see that light activity had an association with lower mortality is intriguing. Based on these results we would recommend adding two minutes of walking each hour in combination with normal activities, which should include 2½ hours of moderate exercise each week."
Beddhu adds that large, randomised, interventional trials will be needed to definitively answer whether exchanging sitting for light activities leads to better health.