Sedentary Lifestyles and Cancer Risk: How Are They Linked?

Sitting and lying down all day may help push physical and mental exhaustion away, but they aren’t exactly beneficial to you in the long run. Different health risks have long been associated with having little to no physical activity, including cancer. No less than the World Health Organization (WHO) identified a sedentary lifestyle as one of the leading causes of death worldwide, accounting for approximately 3.2 million deaths per year. 

If you think enjoying a whole day binge-watching your favorite series or playing a video game on a bed is good for the body and mind, think again. This article serves as a brief guide covering everything you need to know about sedentary lifestyles and cancer. Find out what links the two and why you should embrace a more active routine from now on.

What makes up a sedentary lifestyle?

A sedentary behavior commonly pertains to any activity that requires low energy expenditure. Common examples of sedentary behavior include television viewing, sitting while reading, lying down while playing video games, and more.  

In 2017, the Sedentary Behavior Research Network (SBRN) gave an even more specific definition of what constitutes sedentary behavior. It defined the term as any waking behavior that has an energy expenditure of 1.5 metabolic equivalents (METs) or less. To make this clearer, one MET equals the amount of energy you exert while at rest. Hence, activities that amount up to 4 or 5 METs mean a normal person consumes energy that is 4 or 5 times greater than the energy he uses when he is completely at rest. Activities like sitting while reading or playing cards generally amount to 1 to 1.5 METs. Meanwhile, running or bicycling may already measure over 10 METs.

When sedentary behaviors are done repetitively and take up most of our time, it develops into a lifestyle. In one study, about one-third of people worldwide aged 15 years and above are said to have insufficient physical activities. Another research also revealed that Americans tend to spend 54.9% of their monitored time engaged in sedentary behaviors.

Sedentary lifestyle and Cancer – Is there a connection?

Physical inactivity has long been associated with various health risks, including diabetes, obesity, and cardiovascular disease. Naturally, many are curious whether keeping a sedentary lifestyle also finds a connection with cancer, which is one of the leading causes of death worldwide. Current literature answers this question in the affirmative. Many studies published so far found that keeping a sedentary lifestyle leads to an increased risk of cancer, including breast, colon, and ovarian cancers.

In a 2014 meta-analysis, researchers analyzed data from 43 observational studies with over 68,000 cancer cases. They found that prolonged TV viewing and time spent in other sedentary behaviors such as occupational sitting time lead to increased risks of colon, endometrial, and lung cancer. Researchers noted an 8% and 10% increase in colon cancer risk and endometrial cancer risk, respectively, for every additional two (2) hours of sedentary time per day.

Such a positive association between sedentary behavior and cancer is believed to be caused by several factors. Among these include the following:

  • Obesity

Lack of physical activity is strongly associated with obesity, a condition where the body contains excessive body fat. In recent years, obesity has been found to cause chronic low-grade inflammation. Over time, such inflammation may cause DNA damage, which can lead to cancer. 

Long-term inflammation may also lead to insulin resistance. This condition will in turn propel the body to produce more insulin. Such an increase in insulin level can promote cancer progression.

Obese people also have more fat cells than other people. Such cells produce hormones called adipokines, which can promote cancer cell progression. 

  • Vitamin D deficiency

Maintaining a sedentary lifestyle is almost equal to spending all your days indoors. Naturally, such a routine may eventually lead to Vitamin D deficiency because of a lack of sunlight and a poor diet. Vitamin D is mainly responsible for regulating calcium and phosphorus levels. Naturally, a lack of sufficient Vitamin D negatively affects the body. 

In one study, researchers found that a low amount of calcium, vitamin D, and dairy food intake is significantly associated with an increased risk of colon cancer. Another group of researchers also observed that women regularly exposed to sunlight display lower breast cancer incidence rates.

Some researchers submit that this relation between low Vitamin D and increased cancer risk is due to Vitamin D’s ability to inhibit the development of colon tumors. Another study also suggests that Vitamin D3 analogs and their 24-oxo metabolite help inhibit the growth of breast cancer cells.

To date, the National Academy of Sciences recommends a daily intake of 200 IU of Vitamin D for people aged 1 to 50, and 400 IU of Vitamin D for those 51 years and older.

The Bottom Line

Are you at risk of cancer? Keeping a sedentary life may cost you more than you’ve bargained for. Welcome a healthier life by embracing a more active lifestyle. You may start with simple household chores to put your body on the move and then eventually add other activities that will require more energy expenditure.


If you know someone battling cancer, you may direct them to us here at New Hope Medical Center. Our team of doctors offers a unique combination of traditional, alternative, and holistic cancer therapies. Call us at 480-473-9808 to know more.

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