Sedentary Behaviour and Sedentary Physiology: Sitting Is the New Smoking
James A. Stone, M.D., PhD, FRCPC, FAACVPR, FACC
Most of us spend our days looking after people with documented coronary artery
disease and cardiovascular disease. In North America, where in excess of 5% of the
adult population has symptomatic, documented coronary and cardiovascular
atherosclerosis, this translates into approximately 15 million people. Traditionally,
even before the first data was published from the Framingham Heart Study, we
understood that smoking, physical inactivity, and high-fat diets were not good for
us. However, in the last half a century, as we have increasingly studied the benefits
of physical activity and physical fitness, we have somewhat forgotten about the
importance of minimizing physical inactivity. Recently, the Canadian Society for
Exercise Physiology has published guidelines on minimizing screen time and
sedentary behaviour in children and adolescents. These guidelines are an evidencebased reflection of the scientific observations around increasing rates of obesity
and cardiovascular disease risk factors amongst younger sedentary populations. In
addition to the epidemiological evidence suggesting increases in longevity limiting
health behaviours in younger people, is the emerging scientific information
regarding sedentary physiology. Most of us understand physical inactivity as simply
being a physiologic state where we are not burning calories. Unfortunately,
physical inactivity actually represents the exact polar opposite of physical activity
and is being increasingly recognized as a biological state in which we preferentially
manufacture and store fat calories while simultaneously reducing our basal
metabolic rates to conserve those calories. Hence the reason why exercise
physiologists are suggesting that sedentary behaviour, i.e. sitting, is the new
smoking when it comes to the risk of developing coronary artery disease and
cardiovascular disease. The epidemiological consequences and the personal health
consequences of sedentary biology should be on the radar of all healthcare
professionals but particularly those who are interested in disease prevention as an
integrated part of overall cardiovascular disease care.