Sitting Causes Cancer Even if You Exercise
If the Andrews Sisters had read the latest health news back in 1941 when they sang, "Don't sit under the apple tree with anyone else but me," they might have changed the lyrics to, "Don't sit under the apple tree at all. Climb up that tree and pick those apples yourself." That's because new studies show that sitting for prolonged periods significantly raises your risk of cancer. We already knew that sitting contributed to diabetes and heart disease, but cancer? Yes, cancer! And even more, that risk exists whether or not you exercise regularly, although short exercise breaks during the day can reduce the risk. To stay healthy, you need to do your exercise, but also, refrain from excess non-stop sitting.
According to research presented at the American Institute for Cancer Research (AICR), up to 173,000 new cases of cancer could be prevented annually in the US if people sat less.1 The two types of cancer that seem to be the most influenced by sitting too much include breast cancer, with 49,000 cases annually directly attributed to long periods of sitting, and colon cancer, with 43,000 cases. Scientists also found that less sitting might prevent 37,200 cases of lung cancer, 30,600 cases of prostate cancer, 12,000 cases of endometrial cancer and 1,800 cases of ovarian cancer. And this is a conservative estimate, says Christine Friedenreich of Alberta Health Services in Calgary, Canada, who conducted research on the link between cancer and sedentary lifestyles.
"Sitting time is emerging as a strong candidate for being a cancer risk factor in its own right," says Dr. Neville Owen of Baker IDI Heart and Diabetes Institute in Australia.2 Dr. Owen conducted a study that found that the average American sits for 15.5 hours daily. That's an astonishing figure, when you consider that sleep takes up an additional seven or eight hours for most of us. The most sedentary age groups include teens and adults over the age of 60. As Dr. Owen says, "The amount of time we spend standing up and walking "makes up such a tiny sliver of a person's waking hours." And while exercise certainly does reduce cancer risk, the researchers point out that even those who do the requisite daily 30-minute workout typically spend only three percent of their day in physical activity. It's just not enough to do your daily exercise routine and then collapse into your chair for the rest of the day.
Earlier research turned up similar results. A recent Australian study published a few months ago found that people who spent more than 10 years in sedentary occupations doubled their risk of colon cancer and had a 44 percent increased risk of rectal cancer.3 Last year, Alma Patel of the American Cancer Society led a study of 123,000 individuals and found that mortality risk rose in proportion to the amount of time people spent in their seats, no matter how much exercise those people engaged in.4 She also found that the death-by-sitting syndrome affects women far more than it does men. While women who sat more than six hours per day had a 37 percent higher mortality rate than those who sat under three hours a day, men in the over-six-hour category only had an 18 percent increased risk.
The fact that exercise doesn't cancel out the effects of sitting doesn't mean that it does no good. Patel also looked at the combined effect of extended sitting plus not exercising. She found that female subjects who sat a lot and didn't do much exercise had an astounding 94 percent greater risk of dying early compared to the most active women. Sedentary men who eschewed exercise plus sat for long periods had a 48 percent boost in mortality risk.
Patel also found that sitting triggers diseases other than cancer, and that, in fact, more sedentary people die from cardiovascular disease as a result of sitting than die of cancer.5 She warns that as little as an hour of sitting can undermine health and notes, "Even among individuals who were regularly active, the risk of dying prematurely was higher among those who spent more time sitting… you have to get up and take breaks from sitting"
And that's the key to survival for those of us glued to our seats. Apparently, a mere one- or two-minute break from sitting each hour can make a big difference in health. In Dr. Owen's work, he found that moving for a minute or two leads to smaller waistlines, less insulin resistance, and lower levels of inflammation -- all risk factors for cancer. Apparently, it only takes a few minutes of activity to break up prolonged periods of sitting to decrease levels of cancer-causing compounds in the body such as C-reactive protein, which is associated with inflammation leading to breast cancer, as well as glucose and fat molecules in the blood. "At the basic-science level, Dr. Owen says, "it appears that there are unique physiological processes and pathways associated with sedentary behavior, particularly prolonged sitting."
Jon Barron has said before that the 30 minutes of exercise every day recommended by the experts won't suffice for weight maintenance or fitness. Now it's clear that even an hour of working out falls short of what we need. It's essential to move throughout the day. If you're in a sit-down job, you need to do what Beyonce suggests and "Just Stand Up." By the way, back in the 19th century, people didn't necessarily sit to do office work. In fact, desks specifically made for standing were de rigueur, and so luminaries like Lewis Carroll, Winston Churchill, Charles Dickens, Ernest Hemingway, Thomas Jefferson, George Sand and Virginia Woolf all did their writing standing up.6 Seems like it might be time for doctors to start prescribing this old fashioned practice to prevent later prescriptions for chemotherapy or heart medications. And yes, for you non-traditionalists, there are stand-up executive desks with built-in computer workstations.7
1 Rettner, Rachael. "Prolonged Sitting Linked to Breast and Colon Cancers." 3 November 2011. Scientific American. 8 December 2011. <http://www.scientificamerican.com/article.cfm?id=prolonged-sitting-linked>
2 Kaplan, Karen. "Don't just sit around--it may increase your risk of cancer." 4 November 2011. Los Angeles Times. 8 December 2011. <http://articles.latimes.com/2011/nov/04/news/la-heb-sitting-cancer-risk-20111104>
3 Boyle, T., et al. "Long-term sedentary work and the risk of subsite-specific colorectal cancer." 15 May 2011. American Journal of Epidemiology. 9 December 2011. <http://www.ncbi.nlm.nih.gov/pubmed/21421743>
4 Hellmich, Nancy. "Prolonged Sitting Linked to Colon Cancer, Breast Cancer." 03 November 2011. USA Today. 8 December 2011. < http://yourlife.usatoday.com/health/medical/cancer/story/2011-11-03/Prolonged-sitting-linked-to-breast-cancer-colon-cancer/51051928/1>
5 Doheny, Kathleen. "Is Sitting Too Long a Major Cancer Risk?" 3 November 2011. WebMD. 9 December 2011. <http://www.webmd.com/cancer/news/20111103/is-sitting-too-long-a-major-cancer-risk>
6 "How we work: writing standing up, in bed." Rodcorp. 9 December 2011. <http://rodcorp.typepad.com/rodcorp/2005/02/how_we_work_wri.html>
7 standupdesks.com <http://standupdesks.com/executive_desk.shtml>