Too much sitting increases risk of premature death…
Our modern world is a wonderful place. We have discovered the smallest pieces of matter and distant worlds possibly able to sustain life. We have cured illnesses that used to take the lives of millions and can speak with someone on the other side of the world in real time. We do not have to raise and grow all of our own food and we have (somewhat) successfully developed self-driving vehicles.
However, there are aspects of life today that have come with consequences…
Research has been showing that, although these advances in transportation, communication, and technology is fantastic, they are being associated with significantly reduced physical activity and these reductions are associated with an increase in sedentary behaviors and negative health-related outcomes.
Even when adults meet public health guidelines for physical activity (150 minutes, moderate intensity or, 75 minutes, vigorous intensity), if they sit for prolonged periods of time their health is compromised.
Now, there appears to be a need to shift from finding ways and implementing policies that increase physical activity to, instead, decrease physical inactivity…
These include sitting during commuting, in the workplace, at home, and during leisure time. Activities such as watching TV, reading a book, using a computer, or sitting in pubic transit or in a car would be included. Office-based workers tend to spend about three-quarters of their work day sitting. This, obviously, does not even begin to take in to account the other ~16 hours of the day which are spent not at work, which undoubtedly also involve many other sitting activities. Some estimates say that 60% or more of adults’ waking hours are spent doing sedentary behaviors.
Sit vs. Stand
Some studies are showing that breaks in sedentary time, independent of the overall amount of time spent being sedentary, can have beneficial effects on metabolic biomarkers. This could have been as simple as transitioning from sitting to work at a desk to standing to work at a desk. A higher number of “breaks” was associated with positive changes in waist circumference, body mass index (BMI), triglyceride levels, and 2-hour postprandial blood sugar.
A particularly interesting study done in the Netherlands investigated the effects of sitting less vs. an exercise program in type 2 diabetics. Breaking sitting with standing and light-intensity walking improved 24-hour blood sugar levels and insulin sensitivity to a greater extent than did structured exercise (in an otherwise sedentary day). Both sitting less and exercise had similar results for how much blood sugar levels rose above fasting blood sugar levels during a 24-hour time period (iAUC).
Considering that structured exercise is usually included in most type 2 diabetes treatment and prevention programs, maybe we need to be rethinking the equation. Also, the “sit less” rather than the “exercise more” plan does not seem to carry with it the same dangers for the potential of hypoglycemia, or blood sugars below what is considered to be normal and healthy.
Which brings us to…
The Active Couch Potato
n. Some who is physically active but also engages in a large amount of sedentary time. Example: an office worker who goes to spin class five days a week.
Believe it or not, just meeting the recommended minimum physical activity guidelines is not enough. Turns out, you still need to move around outside of your regularly scheduled workout routine. Otherwise, you may actually essentially cancel out the health benefits you received from being active in the first place.
Active couch potatoes tend to have a larger waist circumference, higher systolic blood pressure, and higher 2-hour postprandial blood sugar (in both men and women) in addition to higher fasting blood sugar and triglycerides and lower HDL-cholesterol (in women) than their counterparts who not only meet activity guidelines, but also do not spend a large amount of their non-exercise hours engaging in sedentary behaviors.
However, there are conflicting studies. One study on Danish adults found that sitting is a risk factor only in those who are obese and inactive when it comes to increased incidence of diabetes. More studies will need to be done, but these findings may indicate that the health consequences of prolonged periods of sitting can be independent of the health benefits of regular moderate-to-vigorous physical activity.
Most studies I came across were in agreement that the best circumstance would be sufficient physical activity combined with low sitting time for cardiometabolic health and that public health strategies should focus on both to reduce chronic disease risk.
Facing Your Own Mortality
In the Canadian Fitness Surveys, Canadians who reported spending most of their day sitting had significantly poorer mortality outcomes than those who reported spending less time sitting.
These times are based on self-reported measures, which participants usually under-report less desirable behaviors and over-report more-desirable behaviors. For example, someone who is surveyed might under-report how many cigarettes they smoke in a day but over-report how many fruits and vegetables they eat.
Benefits were shown even in those who were physically active, and even more so in those who were overweight or obese. Low sitting time individuals had lower rates of all-cause and cardiovascular disease mortality at follow-up compared to high sitting time individuals.
To summarize: It’s not just about moving more, we need to be sitting less.
Even if you are an active individual, it may be a smart move to set time limits on sedentary activities and build in planned “breaks” throughout the day.
References and Studies
– Duvivier, B. M., Schaper, N. C., Hesselink, M. K., Kan, L. V., Stienen, N., Winkens, B., Koster, A., Savelberg, H. H. (2016). Breaking sitting with light activities vs structured exercise: a randomised crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes. Diabetologia,60(3), 490-498. doi:10.1007/s00125-016-4161-7
– Engelen, L., Gale, J., Chau, J. Y., Hardy, L. L., Mackey, M., Johnson, N., Shirley, D., Bauman, A. (2016). Who is at risk of chronic disease? Associations between risk profiles of physical activity, sitting and cardio-metabolic disease in Australian adults. Australian and New Zealand Journal of Public Health,41(2), 178-183. doi:10.1111/1753-6405.12627
– Owen, N., Healy, G. N., Matthews, C. E., & Dunstan, D. W. (2010). Too Much Sitting: The Population-Health Science of Sedentary Behavior. Exercise and Sport Sciences Reviews,38(3), 105-113. doi:10.1097/jes.0b013e3181e373a2
– Petersen, C. B., Bauman, A., & Tolstrup, J. S. (2016). Total sitting time and the risk of incident diabetes in Danish adults (the DANHES cohort) over 5 years: a prospective study. British Journal of Sports Medicine,50(22), 1382-1387. doi:10.1136/bjsports-2015-095648
– Tobin, R., Leavy, J., & Jancey, J. (2016). Uprising: An examination of sit-stand workstations, mental health and work ability in sedentary office workers, in Western Australia. Work,55(2), 359-371. doi:10.3233/wor-162410