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You would never call yourself a couch potato. You log a sweat at the gym nearly every day, after all, even doing double-duty workouts occasionally. You may jump on the bike and circuit the neighborhood or go for a 5K run just to get the blood moving.
Yet ask yourself this: How many hours on average do you sit every day? Probably more than you think, as research indicates that people spend 50 to 60 percent of their waking hours, roughly eight to 10 hours a day, sitting on their duffs. And that amount of sitting, as it turns out, can pose significant health risks.
We can hear you now, saying that you work out regularly, that you’re an active Oxygen reader committed to the fitness lifestyle and you don’t have to worry about sitting so much. Truly stunning — and of interest to the Oxygen woman — is that even if you log 30 to 40 minutes of exercise per day for five days a week, you may reduce the risk of heart attack and stroke and lower blood pressure and cholesterol levels, but you still can pay a price for prolonged sitting.
Following the pioneering work in what is known as “inactivity studies” by Mayo Clinic endocrinologist/researcher James Levine, M.D., Ph.D., there’s been an international explosion of studies looking at the ill effects of prolonged sitting. And the news isn’t good. Sitting for excessive periods is increasingly being linked to assorted health conditions, including heart disease, diabetes, cancer, kidney disease, anemia and bone loss, among others.
• Sitting for prolonged periods allows your body to begin shutting down metabolically. Sitting a full day can lower by up to 50 percent the amount of fat-burning enzymes responsible for managing triglycerides, a blood fat. In time, your good cholesterol, HDL, can drop.
• Because blood flows much more slowly while you sit, fatty acids are much more likely to add to the buildup of plaque in your heart vessels.
• Your pancreas continues to produce insulin, even though inactive muscle responds less and less to insulin, a hormone that controls your blood sugar. This may open the doorway to Type 2 diabetes.
See AlsoSit-Less Strategies
• Unless you use good posture while sitting (few people do), your abdominal muscles weaken while your lower back muscles attempt to compensate, leading to a biomechanically unstable condition called hyperlordosis. In time, you increase the risk of developing ruptured spinal disks. Since the 1990s, lower-back problems among women have soared threefold.
• Because sitting rarely allows you to extend your hip flexor muscles, their range of motion becomes compromised. Your posture and walking suffer, and the loss of flexibility can increase the risk of injuries while you exercise.
• Sitting leads to blood pooling in your lower extremities, opening the dam to assorted health-compromising conditions of the legs, such as deep vein thrombosis. Blood flow in the lower extremities can be compromised by as much as 50 percent after only an hour of sitting.
• Thanks to reduced blood flow and oxygen from prolonged sitting, your brain does not function optimally. You may think you’re multitasking, but you’re likely spinning your wheels.
• Middle-age women who sat longer than seven hours per day showed a 47 percent higher risk for depression than women who sat less than four hours, according to a study published in American Journal of Preventive Medicine.
• “Sitting time is emerging as a strong candidate for being a cancer risk factor. … The phenomenon isn’t dependent on bodyweight or how much exercise people do,” says Neville Owen, head of behavioral epidemiology at the Baker IDI Heart and Diabetes Institute in Australia.
• In a report in the Journal of the American Medical Association, Frank Hu, M.D., Ph.D., of the Harvard School of Public Health, observed that television watching, in addition to showing a relationship to various diseases, also increased the odds of dying from any cause by 13 percent.
• Israeli researchers at Tel Aviv University found that placing fat cells under stress or a load, such as the kind generated on your glutes when you sit, can accelerate the rate by up to 50 percent at which fat cells produce fat. While the study was conducted on lab mice, it may be worth considering as you become more aware of the health risks over long sitting.
• No research to date has found a direct cause-and-effect relationship between long periods of sitting and metabolic dysfunction and disease. However, there appears to be a strong relationship between these events, and it bears watching and taking protective steps.
Standing vs. Exercise: Why You Need Both
As research continues to pour in, even if you log the recommended amount of physical activity (150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise or a combination of the two each week), you’re not immune from the deleterious effects of prolonged sitting, according to a study from the Annals of Internal Medicine.
While excessive amounts of sitting affected everybody in the study, no matter their activity level, researchers did find important differences between people who logged the recommended amount of exercise versus those who didn’t. “Although health hazards associated with sitting were about 15 to 20 percent across the board, that risk rose to 40 percent if you did little or no exercise but dropped to 5 to 10 percent if you met daily exercise recommendations,” says David Alter, M.D., Ph.D., study co-author and cardiologist and senior scientist with the Toronto Rehabilitation Institute at the University Health Network in Canada.
So why doesn’t exercise eliminate all the risks? Namely because daily activity like folding laundry, preparing meals and so on is different from exercise per se; each impacts your body differently. Daily activity, or what you do the other 15 or so hours (not including sleep), is referred to as non-exercise activity thermogenesis. Simply, this refers to the number of calories or energy you burn throughout the day when you’re not exercising.
“With exercise, you’re increasing your heart rate and breathing harder to improve your fitness level, which comes with its own protective benefits,” Alter says. Meanwhile, your daily activity outside the gym actually has a greater impact on calorie expenditure, and that’s one reason Alter believes sedentary behavior, sitting included, is so dangerous.
“By sitting a majority of the day, even if you exercise, you’re creating metabolic toxicity, a fancy term for saying you’re not burning as many calories as you consume,” he says. You burn roughly 50 to 70 calories an hour while sitting versus 120 to 140 calories an hour while standing, Alter adds.
Those unused calories then turn into waste like fat, even lead to poor glucose control, both of which are linked to chronic health conditions. That’s supported by animal research, which has found that there are different physiological problems involved with sitting that exercise can’t necessarily counteract, says Genevieve Healy, Ph.D., senior research fellow at the University of Queensland in Australia.
Your solution to the “sitting disease” is amazingly simple: Stick with those daily workouts, but make every effort to sit less during the day. While experts are still figuring out exactly how much sitting is too much — one study did show that if Americans reduced sitting time to less than three hours a day, life expectancy across the board would increase by two years — Alter suggests this goal: Decrease your sedentary time in a 12-hour span by two to three hours. According to research done in the U.K. by Michael Mosley, M.D., and co-author of The Fast Diet, standing three hours per day for five days each week will alone lead to an 8-pound loss in 12 months, which will lead to improved health.
Just don’t go to the extreme and stand 24/7. “Although we have little knowledge about the health benefits (or detriments) of standing, we do know that too much standing, especially static standing (meaning that you’re in one posture the whole time), can be detrimental,” Healy says. She adds, though, that a study she’s currently leading is showing that replacing sitting with standing does have potential cardio-metabolic effects.
Now, to borrow a line from singer James Brown, are you ready to get up off of that thing and move until you feel better?