More Physical Activity, Less Sitting Helped Fight Obesity

Obesity may result from physical inactivity during leisure time

(RxWiki News) Obesity is a serious condition that can easily develop in adults if they do not lead healthy lives. New research suggests adults should try for a combination of healthy behaviors in order to combat obesity later in life.

A recent study found that people who engaged in both high levels of physical activity and low levels of sitting per week were at the lowest risk for becoming obese after five and 10 years.

The researchers concluded that this combination of high physical activity and low sitting time was significantly more protective against becoming obese than either physical activity or sitting time alone.

"Limit the amount of time you spend sitting each day."

The lead author of this study was Joshua A. Bell, MSc, from the Department of Epidemiology and Public Health at University College London in the UK.

The study included 3,670 British government workers recruited from a previous study. The old study took place between 1985 and 1988.

The authors of the current study recorded data between 1997 and 1999. This period of time was considered baseline.

The patients' average age was 56, and 73 percent were men.

The researchers assessed the participants’ average levels of activity with a survey that asked them how often and for how long they spent doing exercises like walking, cycling, home maintenance and gardening.

The participants who engaged in zero to 1.5 hours of exercise per week were placed in the low-activity group. Those who exercised for 1.56 to 4.25 hours per week were considered to be in the intermediate-activity group, and those who did 4.27 to 20.56 hours of exercise per week were in the high-activity group.

The researchers also asked the participants how many hours per week on average they spent sitting down at home doing things like watching TV, sewing or sitting at a desk.

The low leisure time sitting group consisted of the participants who spent zero to 11.5 hours per week sitting at home. The intermediate leisure time sitting group spent 15 to 23 hours per week sitting at home, while the high leisure sitting group spent 25 to 90 hours sitting at home per week.

Body mass index (height to weight ratio) was measured at baseline, between 2002 and 2004 and between 2007 and 2009. The study authors defined obesity as having a body mass index of 30 or more.

The long-term risks of developing metabolic risk factors include high levels of blood fats, high blood sugar, high blood pressure, insulin resistance and low levels of good cholesterol.

The researchers conducted follow-up screenings at five and 10 years.

The findings showed that the rate of obesity was lower in the high-activity group than in the low-activity group after both five and 10 years. About 5 percent of the high-activity group was obese at five years — versus 8 percent of the low physical activity group. Seven percent of the high-activity group and 12 percent of the low-activity group was obese at 10 years.

The researchers determined that, compared to the low-activity group, the participants in the high-activity group were 36 percent less likely at five years and 37 percent less likely at 10 years to be obese.

However, obesity did not differ according to time spent sitting at either five or 10 years.

The findings also revealed that the participants who were in both the high-activity group and the low-sitting group were 74 percent less likely to be obese after five years and 49 percent less likely to be obese after 10 years than the participants who were in the low-activity group and high-sitting group.

The researchers linked the combination of high physical activity and low sitting with the lowest odds of becoming obese.

Compared to the participants in the low-activity group and the high-sitting group, the participants who were in both the intermediate-activity group and intermediate-sitting group were 47 percent less likely to develop metabolic risk factors after five and 10 years, Bell and team determined.

"The protective effects of moderate-to-vigorous physical activity and low leisure time sitting against developing obesity and metabolic risk factor clustering are strongest when viewed in combination," the researchers wrote. "The effectiveness of physical activity for preventing obesity may depend on how much you sit in your leisure time. Both high levels of physical activity and low levels of leisure time sitting may be required to substantially reduce the risk of becoming obese. Associations with developing metabolic risk factor clustering were less clear. Intervention studies are needed to examine whether a total lifestyle approach, promoting both high physical activity and low leisure time sitting, is most effective at reducing the risk of becoming obese."

The study was limited because data on exercise and leisure time were only recorded at the start of the study, the researchers noted. In addition, much of the data was self-reported.

This study was published July 28 in Diabetologia.

The Economic and Social Research Council, the British Heart Foundation, the US National Institutes of Health, the National Institute on Aging, the Medical Research Council, the National Heart, Lung, and Blood Institute, the National Institute of Aging and the Academy of Finland provided funding for this research.

Review Date: 
July 28, 2014