Is sitting increasing our risk of cancer? According to a recent review of current research, it may be no coincidence that cancer rates and sedentary behavior are both increasing globally. When compared to low sedentary behavior, high sedentary behavior increases the overall risk of cancer by up to an alarmingly 20%.


Sedentary behavior (such as sitting) is linked to increased cancer risk across many types of cancer.

Sitting and cancer risk

What is sedentary behavior, and why is it so harmful? Sedentary behavior is defined as “any walking behavior characterized by an energy expenditure ≤1.5 metabolic equivalents (METs) while in a sitting, reclining, or lying posture”. This includes sitting at work, driving your car, and watching television. Sedentary behavior impacts biologic mechanisms such as metabolic dysfunction, altering circulating levels of sex hormones, and low-grade systemic chronic inflammation. These altered mechanisms all link sedentary behavior to cancer risk. Additionally, sedentary behavior is associated with an increased risk of obesity, which adds another bundle of altered biologic mechanisms that increase cancer risk.


How sitting increases cancer risk

A new study reveals alarming data

In the recent review The Influence of Sedentary Behavior on Cancer Risk: Epidemiologic Evidence and Potential Molecular Mechanisms by Dr. Carmen Jochem, Dr. Birgit Wallmann-Sperlich and Dr. Michael Leitzmann, the researchers unveil how the impact of prolonged sedentary behavior is linked to cancer. When compared to low sedentary behavior, high sedentary behavior increases the risk of colon cancer by 28–44%, risk of breast cancer by 8–17%, and risk of endometrial cancer by 28–36%.

What can we do to reduce our risk?

An important takeaway is that sedentary behavior is an independent risk factor for cancer. It remains unclear whether people who meet the physical activity guidelines of 150 minutes of sports per week are protected by their exercise efforts. For example, a person who goes for a morning run before spending their day sitting at work still probably faces an increased risk of cancer due to this prolonged sedentary behavior. Therefore, steps must be taken to reduce and break up sedentary behavior during these prolonged bouts of sitting, such as in the office. Previous research has shown that most sedentary behavior during the day stems from occupational sitting time and screen time. Therefore, focusing on reducing prolonged sedentary behavior during these high-volume sedentary times may be an important step towards reducing cancer risk.

Colleen Sands

Written by Colleen Sands

Colleen J. Sands is a Master’s student in the University of Massachusetts Amherst Kinesiology Department. She is advised by Dr. Catrine Tudor-Locke. Sands’ primary research interests are physical activity, walking and running gait, and associations with health outcomes. During her undergraduate tenure, Sands captained the University of Massachusetts Division-1 track & field team, and she continues to race competitively in distance running events.