What you may have heard
Low levels of physical activity are linked to increased risk of several types of cancer (NCI).
What science tells us
We know less about the relationship between sedentary behavior (long amounts of sitting or laying down) and cancer risk, but recent research suggests that sedentary behavior is an independent risk factor for cancer risk and mortality.
Epidemiological Evidence
A review of 18 epidemiological studies of sedentary behavior and cancer risk found that there were statistically significant relationships between sedentary behavior and cancer outcomes (Lynch et al). People who spend a higher amount of time sitting or reclining have increased colorectal, endometrial, ovarian, and prostate cancer risk. In addition, sedentary behavior is associated with increased cancer death in women. These results were confirmed in a 2020 cohort of 8,002 black and white adults: sedentary behavior is an independent risk factor for cancer risk and mortality.
Laboratory Evidence/ Supportive Evidence
Laboratory evidence using animal models to examine the relationship between exercise and cancer development have focused on the reduction of cancer risk with exercise, which is shown to be effective. More research is needed examining sedentary or low activity in animal models and the development of cancer.
IARC Carcinogen Classification:
Not classified.
How to reduce your risk
Recommendations to decrease your risk of weight gain, obesity and several types of cancers include: 150-300 minutes of moderate-intensity cardio weekly, 75-100 minutes of vigorous cardio weekly, and muscle-strengthening training at least two days a week (CDC).
Bottom line
Sedentary behavior increases cancer risk and mortality. Decrease your risk of cancer by doing at least 30 minutes of exercise each day.
Check out these short videos about physical acitivty and cancer risk from the Dana-Farber Cancer Institute and the World Cancer Research Fund.