A growing body of inactivity research is beginning to suggest that the notion of regular fitness countering the effects of sitting makes about as much sense as the idea that one might be able to counter a pack-a-day smoking habit simply by jogging.
Regardless of where the sitting takes place–at work, at school, in the car or in front of a computer or TV–the overall number of hours spent without movement add up to an increased risk of deleterious effects on one’s health, including the shortening of one’s life span. While the President’s Council on Fitness, Sports & Nutrition has done a very good job of delineating the number of hours of exercise which are recommended for optimal health, there seems to be a frightening lack of recommendations for limiting the amount of prolonged sitting in which one engages on a daily basis.
Exercise, in itself, though obviously critical to our physical well-being, does not seem to sufficiently counter the damaging effects of remaining motionless for hours on end. According to Marc Hamilton, an inactivity researcher at the Pennington Biomedical Research Center, excessive sitting causes electrical activity in the muscles to drop. This in turn causes a cascade of harmful metabolic effects. The body’s calorie-burning rate immediately plummets to about one calorie per minute, a third of what it would be if the sitting were interrupted by even a brief walk to another room. Insulin effectiveness drops within a single day, leading to an increased risk of developing Type 2 diabetes. The enzymes responsible for breaking down fats and triglycerides in the bloodstream also become significantly lowered, which in turn causes the levels of HDL (“good cholesterol”) to fall.
Sadly, metabolic energy is not the only bodily system affected by excessive bouts of inactivity. Tom Manley, Director of Scientific Activities for the National Kidney Foundation, recently announced that current research provided more than merely a statistical link between sitting and chronic kidney disease. By measuring a kidney’s ability to filter wastes, easily identified by the presence of the protein albumin in the urine, researchers were able to demonstrate that prolonged sitting led to elevated levels of albumin in the urine of test subjects, revealing poor kidney function. This risk of kidney disease seems to be more prevalent for women than for men.
The American Institute for Cancer Research has also, independently, weighed in on the topic, with equally dismal news. Their studies focused on the approximately 49,000 new cases of breast cancer and 43,000 new cases of colon cancer seen each year. A sedentary lifestyle, which encompasses prolonged periods of sitting, may have contributed to these cases. Though, according to research, breast and colon cancer appear to be the cancers most directly influenced by physical inactivity, the published article also claims that approximately 37,200 new cases of lung cancer, 30,600 cases of prostate cancer, 12,000 cases of endometrial cancer and 1,800 cases of ovarian cancer might also have been prevented by individuals being more physically active on a regular basis.
Given that so many of us are tied to desk jobs, or have long commutes to and from work each day, just how much sitting is considered to be breaching the danger zone? One particularly disturbing study revealed that uninterrupted sitting for 6 hours a day can shave 5 years off one’s life expectancy. Sedentary females, even those who exercise regularly, may be 37% more likely to die prematurely than their counterparts who remain inactive for less than 3 hours each day, even if they too engage in the same amount of regular exercise. For excessively sedentary males, the risk seems to be only 18% higher than for those men who move around more during their busy day.
Dr. James A. Levine of the Mayo Clinic has coined a term that is useful in helping to counter the effects of sitting: NEAT, which stands for Non-Exercise Activity Thermogenesis. This concept of NEAT encompasses the ideal that even the smallest of motions matter. Interrupting long bouts of sitting with a simple 2-minute break of light activity such as walking can help to control insulin levels. According to research conducted by Dr. Michael Jensen, also of the Mayo Clinic, individuals whose bodies make frequent little movements, such as taking the stairs, trotting down the hall to see a co-worker, doing chores at home or simply fidgeting, are at a huge advantage.
Even for individuals who are otherwise very active, sitting for long stretches of time seems to be an independent risk factor for developing conditions such as diabetes, cardiovascular disease, cancer and kidney disease. Some professionals have taken this news to heart and have installed treadmills in their offices in place of desk chairs, set at an appropriate eye level to their desk or computer.
If one moves slowly on the treadmill, a normal cadence soon can become rhythmic enough so as to not interrupt the flow of mental energy required by a demanding “desk job”. Any movement, even standing, is preferable to prolonged bouts of sitting. If a treadmill in your office is not feasible, and commute time is the main culprit, find ways to take frequent breaks, even if it is to stand up and move your limbs for a few minutes. As the NEAT theory demonstrates, even the most minor of movements (standing up and walking to the TV to turn it off instead of using the remote, for example) will work in your favor. Add years to your life–healthy years–by simply becoming a verb!
4. Bharakhada, N., American Journal of Kidney Diseases, October, 2012. 5. CDC: “National Chronic Kidney Disease Fact Sheet 2010.”
11. USA Today.com: Nancy Hellmich, “Prolonged Sitting Linked to Breast Cancer, Colon Cancer” (accessed 4/16/12)
12. Scientific American.com: Rachel Retner, “Prolonged Sitting Linked to Breast and Colon Cancers” (accessed 4/16/12)
About the Author
Cathleen Kronemer is an AFAA-Certified Group Exercise Instructor, NSCA-Certified Personal Trainer, competitive bodybuilder and freelance writer. She is employed at the Jewish Community Center in St. Louis, MO. Cathleen has been involved in the fitness industry for 22 years. Look for her on www.WorldPhysique.com.
She welcomes your feedback and your comments!