Over the last decade, you may have heard the saying “sitting is the new smoking”. Though research has proven the saying is an exaggeration, scientists also agree that humans are meant to move. Here’s what a combination of excessive sitting (8+ hours per day) and minimal movement is doing to you.
Healy and colleagues conducted a study that evaluated how sedentary time, sedentary time with light breaks, light physical activity, and moderate to vigorous physical activity (MVPA) affect cardiovascular and metabolic risk factors. The findings revealed that those who took fewer breaks had larger waist circumference and higher blood glucose levels than those who took more frequent breaks.
Moreover, independent of total sedentary time, the total number of breaks was significantly related to lower resting blood pressure, body mass index (BMI), triglycerides, and two-hour fasting plasma glucose levels.
All-Cause and Cardiovascular Disease Mortality
Sitting for prolonged periods of time with little to no physical activity increases all-cause and cardiovascular disease mortality risk among the least physically active adults (Stamatakis et al., 2019). A 1981 Canada Fitness Survey found that greater total daily sitting time was associated with higher risks of death from cardiovascular disease (CVD) and all causes. An Australian study by Dunstan and colleagues among 8,800 Australian adults revealed similar results.
Researchers, Schmid and Leitzmann examined 68,936 cancer cases. Observing the relationship between sedentary behaviour and cancer, they looked at lower and higher durations of daily television viewing time. The findings showed significantly increased risks of colon (8%) and endometrial (10%) cancer, for each two-hour increase in daily sedentary time. They also discovered a connection between higher durations of sedentary time and a greater risk of lung cancer.
Shen and colleagues also found an association between prolonged sedentary behaviour and increased risk of breast, colorectal, endometrial, and lung cancers.
How Can You Reduce Your Cardiometabolic, All-Cause and CVD Mortality, and Cancer Risks?
There’s a huge body of evidence that supports the notion that sitting for too long, regardless of the amount of time spent in MVPA, is harmful to human health. To reduce your risk of injury and illness, avoid sitting for extended periods of time and take a lot of movement breaks. Light physical activity may reduce some of the negative effects of prolonged sitting.
Stamatakis E, Gale J, Bauman A, Ekelund U, Hamer M, Ding D. Sitting Time, Physical Activity, and Risk of Mortality in Adults. J Am Coll Cardiol. 2019 Apr 30;73(16):2062-2072. doi: 10.1016/j.jacc.2019.02.031. Erratum in: J Am Coll Cardiol. 2019 Jun 4;73(21):2789. PMID: 31023430.