Sitting – The new smoking or the new sensationalism?

BY SARA KNAEPS. Media tells us that sitting is the new smoking, sitting kills or even this: chairs are murderers. But is this true? First of all, if it would be true, we would go to a future where we have to be 18 years or older to buy a chair, and a lovely little bench in the park will not be the same anymore with signs warning for the dangers of sitting. I am probably exaggerating, but if sitting would really be the new smoking, this is where we are going.

Written by doctoral student Sara Knaeps. Sara researches the negative consequences of sitting. She gave a presentation on this topic at Ted-X Leuven.

Sara Knaeps

According to data of the World Health organization, every year world wide a total of 5.1 million people die because of tobacco use. That is 1.9 million people more than because of physical inactivity, which is due to insufficient physical activity but also increases in sedentary behavior 1. I could stop here and conclude: sitting is not the new smoking.

However, if we take a closer look at these numbers, we see that sitting is a serious health risk behavior.

According to the WHO physical inactivity is the fourth biggest preventable mortality risk factor and 3.2 million deaths a year could have been avoided if everyone were more active and sat less. Furthermore, for cardiovascular disease and cancer there is an increased risk. It might not be as large as for smoking, it is still a serious increase in risk. And then I left out the risks for diabetes, the metabolic syndrome, depression, muscle and joint pain, and the quality of our lives.

So what happens when we sit too much? Our metabolism gets affected, we produce less enzymes that help break down fat, our good cholesterol decreases and the effectiveness of insulin drops. Up till now, we do not exactly know the underlying pathways, but what we do know from multiple studies is that high sitting time is a health risk behavior for multiple diseases and discomforts.

What we do know from multiple studies is that high sitting time is a health risk behavior for multiple diseases and discomforts.

Again, I could stop here and end with sitting is not the new smoking, and when we sit less, we can reduce chances of disease and increase the chance for a long and healthy life. But I think that it is not only important to focus on what can go wrong, but much more important to know what the guidelines are and what we can do to reach these guidelines.

We spend half our waking hours sitting down

Do you have any idea how many hours a day you sit? Of course, if you are an office worker, you will think about all the hours you sit at your desk. Maybe you will also realize you are sitting quite a lot when watching television. However, we also sit when we eat, travel, work or when we relax while reading a book, doing some knitting or going for a drink with friends.

On average a Flemish adults sits nearly nine hours a day 2. This means that half of the time we are awake is spent sedentary. It looks impossible to ban sitting out of our lives, therefore some good news: we do not have to stop sitting completely, but try to reduce and break down our sitting time.

We do not have to stop sitting completely, but try to reduce and break down our sitting time.

Research has shown that eight hours a day seems to be some sort of threshold. When a person, all together, sits less than eight hours a day, risks seem to drop significantly. Furthermore, according to national and international guidelines, the time we sit needs to be broken down in bouts of roughly 20 to 30 minutes. We do not have to be very active, just go to the toilet, get a cup of coffee or stand up for a minute.

However, it is important to realize that sport and sitting time are not complements. Meaning that when we perform sport it will not only replace sitting time. Usually we perform less light physical activity and decrease our sitting time only a little. We even have a term for people who sit all day and are very active for a short time. We call them the active couch potatoes. So for everyone who is already performing a lot of sport, really good, sport is healthy, but also have a look at your sedentary time, it is still possible that it is too much.

Get up! How to make the change

To end I just have a few tips to reduce our sedentary time.

There are a lot of occasions where the switch from sitting to standing is easily made.

The good news is that we do not have to completely change our behavior, however we do have to try to break up our sedentary time and try to get under the eight hour limit. Some small tips for office workers is to make phone calls standing, do not use e-mail to communicate to colleges on the same floor, put your printer in the corner of the office, have walking meetings and maybe think about getting a sit-stand desk.

General tips are: Try to take the bike or walk, and when watching television every time there is a block of advertising stand up and do something. I am not suggesting you get unhealthy snacks, but just stretch your legs. Finally, it is important to become aware of when, where and how long you sit. There are a lot of occasions where the switch from sitting to standing is easily made.

So my main message is: Although sitting might not the new smoking, sitting is a health risk behavior and we should try to reduce it, break it up in bouts of roughly 20 to 30 minutes and try to adopt an active lifestyle.



[1]  World Health Organization (2009) Global Health Risks – Mortality and burden of disease attributable to selected major risks.

[2]  Van Acker R, De Meester F (2015) Langdurig zitten: dé uitdaging van de 21ste eeuw -Syntheserapport als actuele onderbouw voor de factsheet sedentair gedrag. . In. Vlaams Instituut voor Gezondheidspromotie en Ziektepreventie, Brussel

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