Study suggests both high physical activity and less sitting in leisure time may be required to reduce risk of obesity

July 29, 2014

New research published in Diabetologia (the journal of the European Association for the Study of Diabetes) suggests that both higher levels of physical activity and lower levels of sitting in leisure time may be required to substantially reduce the risk of obesity. The research is by Joshua Bell and colleagues, Department of Epidemiology and Public Health, UCL (University College London), UK.

Physical activity and sitting time (or 'sedentariness') are two common lifestyle-related behaviours associated with obesity and metabolic health, as well as with chronic diseases such as type 2 diabetes and cardiovascular disease, and with all-cause mortality. Studies often consider physical activity and sitting individually; however, these behaviours are closely linked, with modern-day inactive lifestyles being characterised by both insufficient physical activity and excessive leisure time sitting. Evidence on their combined effects is limited. Thus in this new research, the authors aimed to investigate the combined effects of physical activity and leisure time sitting on long-term risk of developing obesity (defined as ≥30 kg/m²) and of developing a clustering of (defined as having two or more of low HDL (or 'good') cholesterol, high levels of blood fats, , , and insulin resistance).

The duration of moderate and and of leisure time sitting was assessed by questionnaire between 1997 and 1999 among 3,670 participants from the Whitehall II cohort study of British government employees (73% male; mean age 56 years). The odds of developing obesity and of developing metabolic risk factor clustering after 5 and 10 years were calculated for adults with different levels and combinations of physical activity and leisure sitting time.

The researchers found that physical activity, but not leisure time sitting, was associated with becoming obese. However, the lowest odds of becoming obese after 5 years were observed for individuals reporting both high physical activity and low leisure time sitting (nearly 4-fold lower odds compared with those reporting both low physical activity and high leisure time sitting). This effect appeared weaker after 10 years, which might be due to misclassification errors resulting from changes in physical activity and leisure time sitting during the follow-up period which were not possible to consider in the present study.

Compared with individuals reporting both low physical activity and high leisure time sitting, those with intermediate levels of both physical activity and leisure time sitting had nearly 2-fold lower odds of having metabolic risk factor clustering after 5 years, with similar odds after 10 years.

The authors say the results persisted even when adjusted for a wide range of potentially confounding factors, including socioeconomic status, smoking behaviour, alcohol consumption and health status.

The authors say: "These findings add to the literature by suggesting that the combination of high physical activity and low leisure time sitting is a stronger protective factor against becoming obese than either behaviour on its own."

Discussing the possible reasons for the results, the authors say: "The mechanisms underlying this interaction are unclear. In principle, lower levels of leisure time sitting may strengthen protective effects of higher physical activity, either through independent physiological mechanisms or as a marker for greater engagement in low-intensity activity, such as standing. Physical activity and leisure time sitting combinations may also simply represent incremental increases in energy expenditure, with the lowest physical activity/highest leisure time sitting group expending the least amount of energy overall, and the highest physical activity/lowest leisure time sitting group expending the most."

They add: "The greatest reduction in risk of developing metabolic risk factor clustering observed for intermediate levels of physical activity and leisure time sitting was unexpected and suggests that moderate amounts of both moderate-to-vigorous physical activity and leisure time sitting may be sufficient to protect against developing metabolic risk factor clustering over time... The lack of protection for the most active adults may reflect a chance finding, or confounding by other factors such as wider use of prescription drugs by participants in less active groups. This result may also be due to changes in physical activity and sitting over the duration of follow-up."

They conclude: "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 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 and low sitting, is most effective at reducing the risk of becoming obese."

Explore further: Physical activity cuts mortality in colorectal cancer survivors

Related Stories

Physical activity cuts mortality in colorectal cancer survivors

January 23, 2013
(HealthDay)—For patients with invasive, non-metastatic colorectal cancer, increased recreational physical activity is associated with reduced all-cause mortality, while prolonged sedentary time correlates with increased ...

Physical fitness associated with less pronounced effect of sedentary behavior

July 14, 2014
Physical fitness may buffer some of the adverse health effects of too much sitting, according to a new study by researchers from the American Cancer Society, The Cooper Institute, and the University of Texas. The study appears ...

Life-changing events can lead to less physical activity

June 6, 2014
Adults tend to engage in less leisure-time physical activity (LTPA) after changes in both lifestyle and physical status, finds a new study in the American Journal of Preventive Medicine.

Exercising more, sitting less reduces heart failure risk in men

January 21, 2014
Sitting for long periods increases heart failure risk in men, even for those who exercise regularly, according to new research published in the American Heart Association journal Circulation: Heart Failure.

Paid work a 'barrier to exercise' for older women

July 1, 2014
(Medical Xpress)—Older women in paid employment are less likely to take part in leisure-time physical activity, according to research by the University of Birmingham.

Physical activity is beneficial for late-life cognition

April 9, 2014
Physical activity in midlife seems to protect from dementia in old age, according to a study carried out at the University of Eastern Finland. Those who engaged in physical activity at least twice a week had a lower risk ...

Recommended for you

Study finds 90 percent of American men overfat

July 24, 2017
Does your waist measure more than half your height?

Are sugary drink interventions changing people's behaviour?

July 19, 2017
An evaluation of efforts designed to reduce how many sugary drinks we consume shows some success in changing younger people's habits but warns they cannot be the only way to cut consumption.

Young adult obesity: A neglected, yet essential focus to reverse the obesity epidemic

July 18, 2017
The overall burden of the U.S. obesity epidemic continues to require new thinking. Prevention of obesity in young adults, while largely ignored as a target for prevention and study, will be critical to reversing the epidemic, ...

Weight gain from early to middle adulthood may increase risk of major chronic diseases

July 18, 2017
Cumulative weight gain over the course of early and middle adulthood may increase health risks later in life, according to a new study led by researchers from Harvard T.H. Chan School of Public Health. They found that, compared ...

Study finds children carry implicit bias towards peers who are overweight

June 23, 2017
Even children as young as 9 years old can carry a prejudice against their peers who are overweight, according to a new study led by Duke Health researchers. They might not even realize they feel this way.

Mother's obesity boosts risk for major birth defects: study

June 15, 2017
Children of obese women are more likely to be afflicted by major birth defects, including malformations of the heart and genitals, according to a study published on Thursday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.