Do you have a job that requires you to sit for long periods of time?

Perhaps in front of a computer? Or do you sit for prolonged periods to watch TV or surf the web? Well then you are in the same category as most Americans. And apparently this simple act of sitting for long periods of time can potentially cause certain types of cancer.

Reuters reports on the surprising new link between sitting and cancer. The research about the connection between the two was recently published in the Journal of the National Cancer Institute this week. Does it sound shocking? How can sitting for a long time cause cancer? What usually comes to your mind when you think of cancer causing mechanisms? Most people think of cigarettes, genetics, obesity and other related things. Could you have ever guessed that something as simple as sitting could cause cancer? New reviews show that it is a strong possibility. Apparently people who spend more time sitting have a higher chance of being diagnosed with colon or endometrial cancer than those who lead active lifestyles. Why? There are a number of reasons that account for the connection.

What kinds of ‘sitting’ activities does this include? The study mostly included people who said they regularly sit for long periods to watch television or because it is required for their job (constantly sitting in front of a computer etc.). Prolonged sitting is also connected to diabetes and heart disease.

The study took on a relatively broad approach; so can it be said that sitting causes cancer?

Well, Fox says, “Observational studies like the ones used in this review can’t prove that sitting causes cancer, and it is possible that people who sit a lot tend to do other things that increase their cancer risk, but studies account for that.”

Since the study does account for those other factors, its findings about the link are note-worthy.

How was the research review conducted? Was it comprehensive? The review actually includes an analysis of tens of studies using thousands of people.

“In total, the 43 studies analyzed by Schmid and her coauthor followed close to 69,000 cancer patients. For every two-hour increase in sedentary time per day, on average, colon cancer risk increased by eight percent and endometrial cancer risk increased by ten percent,” according to Reuters.

The authors found that the risk of cancer was actually even higher for those who watched TV for long periods than those who sat for long periods to do work. Why the discrepancy? The difference probably exists because TV watching is usually also associated with bad eating habits. Many like to munch on snacks such as chips and frozen treats (mostly referring to processed and other similar types of foods) that are unhealthy for the body.

CBS further delves into what the new research means. 

“The goods news is, being sedentary did not appear to be linked to every kind of cancer. Scientists found no relationship between sitting and breast, ovarian, testicular or prostate cancers, or cancers of the stomach, esophagus and kidneys, or non-Hodgkin lymphoma. The bad news was that there was a consistent relationship between hours spent sitting and an increased risk for colon and endometrial cancers. People who spent the most time sitting during the day had a 24 percent increased risk of getting colon cancer compared to those who logged the least number of hours in a chair. When the researchers looked just at time spent watching TV, the risk jumped even more. Those who clocked the most hours glued to the tube had a 54 percent increased risk of colon cancer compared to those who watched the least.”

Was there a control variable for gender? Were men more affected by TV watching or women?

Watch out ladies, you are at a higher risk. CBS explains,

“For endometrial -- or uterine -- cancer, the risks were even higher. There was a 32 percent increased risk for women who spent the most time seated compared to those who sat the least, and a 66 percent increased risk for those who watched the most TV, the study authors said. Moreover, every two-hour increase in sitting time was linked to an 8 percent increased risk of colon cancer and a 10 percent increased risk of endometrial cancer.”

Experts were a little surprised about the fact that women were actually at a higher risk.

Dr. Colditz (a chronic disease epidemiologist) co-authored a foreword for the study but was not involved in the research and issued an objective statement saying, “We evolved over thousands of years with a good amount of activity in daily life - we have removed activity at work, in commuting, and largely at home – all in the relatively short time of 150 years or less. The physiologic effect of refined carbohydrates and so forth add to the adverse effect of not exerting much effort in activity throughout the day. People with the most sedentary jobs had the highest death rates from colon cancer, and postal workers, who walked quite a bit for their jobs, had the lowest.

Endometrial cancer is the cancer most strongly linked to obesity – and since sitting is directly related to weight gain, diabetes and so forth, this fits too.” 

How can you change your propensity to get cancer (especially if you sit for long periods of time)?

The upside here is you do not have to take cancer sitting down. You can stand up, and fight back. Even if sitting contributes to cancer, you can change that by changing your lifestyle. So how much sitting is dangerous? Should you stop watching TV?

No, researchers say the best solution would be a balanced lifestyle that includes a good amount of exercise. Experts are not saying to go to the extreme.

Rather they are suggesting that people simply try to lead more active lifestyles by adding some walking to their day. They are suggesting that people either get a work out in the morning a few days a week (jogging, gym, walking, bicycling etc.) or go walking during their lunch breaks. Basically, you do not want to be a couch potato.

“The risks remained even for ‘active couch potatoes’ -- folks who squeeze in some time at the gym but still spend most of their day off their feet. This suggests that regular exercise can't offset the risks of too much sitting,” according to CBS.

Therefore it is important to be as active as you possibly can.

How does exercising help prevent cancer and control couch potato syndrome? Why is it important?

Many people have difficulty incorporating exercise time into their every day lives, especially with the busy work schedules many New Yorkers face. Dr. Colditz explains why exercising is important though...

“High blood sugar and high insulin is a clear sort of pathway to colon cancer, and we know from intervention studies that walking lowers insulin and getting up after meals lowers blood sugar compared to sitting. As for endometrial cancer, obesity is a phenomenally strong cause. In fact, it is the main modifiable risk factor for endometrial cancer. So for me, the likely scenario there is that the sitting, the weight gain and obesity really go together and exacerbate the risk of endometrial cancer.”

So doing simple things such as walking, getting up after meals and perhaps cutting down on TV time (if you usually sit in front of the TV for hours at night) can greatly reduce your risk of getting these cancers.

These recommendations pertaining to physical activity and exercise apply to everyone, not just those people who are particularly at risk (due to some genetic factors etc) for inheriting any of these cancers. Fox quoted the study's lead author Dr. Schmid as saying,

“This recommendation is not limited to people at risk but also applies to the general population, who will benefit from being more active and sitting less.”

Not only will this change in lifestyle help prevent cancer but it will also help reduce the risk of diabetes and heart disease (two leading health issues in the U.S. right next to cancer). 

Gerry Oginski
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