Less Activity + More Sitting = Obesity Risk

Joshua Bell, MSc Department of Epidemiology & Public Health University College London MedicalResearch.com Interview with:
Joshua Bell, MSc
Department of Epidemiology & Public Health
University College London

 

Medical Research: What are the main findings of the study?

Answer: We found that physical activity and leisure time sitting interact to affect the long-term risk of becoming obese, with protective effects of high physical activity depending upon low levels of leisure time sitting. Adults engaging in both high physical activity and low leisure time sitting showed nearly 4-fold lower odds of becoming obese after 5 years, compared with those engaging in both low physical activity and high leisure time sitting.

Medical Research: Were any of the findings unexpected?

Answer: Our findings for developing metabolic risk factor clustering were unexpected. Compared with adults reporting low physical activity and high leisure time sitting, those reporting intermediate levels of physical activity and leisure time sitting showed the lowest odds of developing metabolic risk factor clustering after 5 and 10 years. The most active adults (those with high activity and low sitting) did not show reduced odds. A large body of evidence supports a dose-response relationship between physical activity and metabolic health, with more activity conferring greater benefits, and we expected our results to agree with this. Results in this case may be due to chance, or confounding by factors which were not accounted for, such as the full range of prescription drugs used by adults in different activity groups. This result may also be due to changes in activity and sitting over the duration of follow-up.

The protective effects of physical activity against becoming obese may depend upon how much time is spent sitting in leisure, and thus, it may be important for adults to pay more attention to how they use the time in which they are not being purposefully active. Both high physical activity and low leisure time sitting may be required to substantially reduce risk of obesity. The mechanisms underlying this interaction are unclear; however, lower levels of sitting may strengthen protective effects of high physical activity by serving as a marker for greater engagement in light intensity activity, or for other protective factors, such as a better diet.

Medical Research: What recommendations do you have for future research as a result of this study?

Answer: Longitudinal studies using objective measures of physical activity and leisure time sitting combinations are needed to confirm our findings. Intervention studies are also needed to examine whether obesity is best prevented by improving levels of both physical activity and leisure time sitting.

Citation:

Combined effect of physical activity and leisure time sitting on long-term risk of incident obesity and metabolic risk factor clustering https://medicalresearch.com/wp-admin/post.php?post=6653&action=edit
Joshua Bell and colleagues, Department of Epidemiology and Public Health, UCL (University College London), UK.
Diabetologia Monday 28 July 2014