Walking two minutes every hour can reduce risk of early death
Previous research has found that a sedentary lifestyle is linked to poorer health and premature death, but a new study suggests that walking just two minutes every hour a day can offset the risk of death linked to prolonged sitting.
Prolonged sitting has also been linked to diabetes, heart disease, and other chronic health problems. But researchers found that, while low-intensity activity such as standing may not be enough to offset the effect of sitting for long periods, adding two minutes of walking per hour to a weekly routine of moderate exercise may decrease the chances of premature death.
Researchers analyzed data on 3,626 participants in the 2003-04 National Health and Nutrition Examination Survey (NHANES), 383 of whom had chronic kidney disease. Participants were asked to wear accelerometers for several days to monitor the intensity of their physical activity. During a three-year follow-up period, 137 participants died.
Based on the accelerometer readings, the researchers were able to determine how many minutes per hour were spent on sedentary (less than 100 accelerometer counts per minute), low (100-499), light (500-2,019) and moderate to vigorous (2,020 and over) activity.
The researchers then examined the mortality of two minutes per hour less of sedentary time spent in low, light or moderate to vigorous activity durations. The mean sedentary duration was 34.4 minutes per hour for the entire cohort, and 40.8 for those with chronic kidney disease.
While there was no benefit to decreasing sitting time by two minutes per hour and replacing it with two minutes of low-intensity activity, such as standing, the researchers found that trading two minutes of sitting for two minutes of light-intensity activity was linked to a 33 percent lower risk of premature death.
"It was fascinating to see the results because the current national focus is on moderate or vigorous activity," said study lead author Srinivasan Beddhu, professor of internal medicine at the University of Utah School of Medicine in Salt Lake City. "To see that light activity had an association with lower mortality is intriguing."
Beddhu said even short periods of light activity add up when repeated over the course of a week and could bring the participant closer to reaching the recommended amount of moderate exercise. The American Heart Association (AHA) recommends adults get at least 150 minutes a week of moderate-intensity exercise, or 75 minutes a week of vigorous exercise.
"Based on these results we would recommend adding two minutes of walking each hour in combination with normal activities, which should include two and a half hours of moderate exercise each week," Beddhu said.
However, the researchers noted that 80 percent of Americans do not meet the AHA's recommendation.
The researchers also concluded that patients with chronic kidney disease are sedentary nearly two-thirds of the time, and that replacing sedentary duration with an increase in light activity duration could be beneficial for preventing premature death.
While the study strongly suggested that two hours of light activity every hour reduced the risk of premature death, it did not conclusively prove it. The study was published in the Clinical Journal of the American Society of Nephrology.
A 2011 study suggested that vigorous exercise lowers the chances of dying from chronic disease by almost 40 percent. Every extra hour of activity added per week reduced a person's chance of dying by 4 percent, compared with people who are sedentary.