Three years ago, Women's Health was among the first to expose sitting disease. The gist: Too much inactivity can leave you prone to such deadly ailments as heart disease and obesity. The advice: Get moving. But Americans haven't budged much. The only real momentum has been in the lab, where research has found that inactivity can also damage your mind, sleep cycle, and organs. It could even shorten your life: Women who sit for more than six hours a day have a roughly 40 percent higher risk of dying from any cause, regardless of their fitness level, versus those who sit for fewer than three hours.
"The human body evolved to move around," says James Levine, M.D., Ph.D., a professor of medicine at the Mayo Clinic. "Yes, there are times to sit, but we put our feet up now more than ever. It's unnatural and hazardous to our health." Young women are especially prone: Research shows they spend more time on their bums than others. Devastating news, considering immobility can start wreaking havoc quickly. Behold, the science behind sitting disease and how to sidestep its risks.
When you're plopped in a chair for hours, gravity and a lack of circulation can cause fluid buildup in your lower legs. An unsexy pair of cankles isn't the worst of it: When you later lie down to sleep, that fluid migrates to the muscles and tissues of your neck and may force your throat to swell, says Douglas Bradley, M.D., director of The Centre for Sleep Medicine and Circadian Biology at the University of Toronto. You may have a harder time sucking in air and might even stop breathing for short periods during the night, a serious condition called sleep apnea that can leave sufferers feeling zombie-like.
It's not just mindlessly sucking down calories that adds junk to your trunk. A recent cell culture study found that when you sit for long periods of time, the weight your body puts on your fat cells actually encourages them to create twice as much fat—at a faster rate—as when you're standing. And you're gaining the worst kind of chub. "When we sit or lie on fat cells, they produce more triglycerides, the type of fat that can raise stroke risk," says study author Amit Gefen, Ph.D., a biomedical engineer at Tel Aviv University in Israel.
Your Blood Sugar
Every time you tuck into a meal, your blood sugar spikes and "you get this huge four-hour crush of calorie-storing activity in the body," explains Levine. Recent research shows too much lolling around could turn this typically normal process into a dangerous one. When otherwise healthy people halved the number of steps they took per day, their blood sugar spikes increased after each meal, no matter what type of fare they ate. "We know these increased post-meal spikes are linked to a higher risk for type 2 diabetes," says John P. Thyfault, Ph.D., an associate professor of exercise physiology at the University of Missouri.
Ummm, what? The more you sit around, the more likely you are to fall prey to so-called senior moments. Your noggin's hippocampus, or memory center, deteriorates as you age, but the side effects of being sedentary (obesity, diabetes) can push that process along. On the flip side, physical acitivity can beef up the size of your hippocampus, says study author Kirk Erickson, Ph.D., of the University of Pittsburgh.
Something as simple as breathing can get gunked up by too much chair time. Sedentary women have more than double the risk of developing a pulmonary embolism, a.k.a. a blood clot in the lungs. "Prolonged sitting makes your blood flow sluggish and more likely to form clots, which can become lodged in your lungs," explains Christopher Kabrhel, M.D., M.P.H., an emergency medicine physician at Massachusetts General Hospital. The more you sit, the higher your risk, and women who take oral contraceptives (which increase blot-clot risk) should be extra mindful.
The Anti-Sit Solution
All of the above effects are easily avoidable (yes, even if you're a desk jockey), and you don't have to get extreme at the gym. Extra-vigorous, push-till-you-drop workouts likely won't be enough to combat sitting disease—they may even make things worse. First, sweat sessions might make you think you're immune to the side effects of being sedentary. In reality, working out and limiting time spent sitting are key for overall health, says Alpa Patel, Ph.D., an epidemiologist at the American Cancer Society.
Second, "if you've been sitting all day, your lower back, hamstrings, and hip flexor muscles are all in tightened positions," explains Michael Frederickson, M.D., a professor of sports medicine at Stanford University. "When you jump too quickly into hard-core exercise, your muscles are more susceptible to injury." (Your back is particularly at risk.)
Of course, you shouldn't quit your heart-healthy workouts altogether. The key to fighting sitting disease lies in augmenting your routine with something called NEAT, or nonexercise activity thermogenesis. Translation: low-impact movements that keep your metabolism humming and your circulation flowing. Cooking qualifies, as does sex, or gardening, or even cruising the office for a gossip break. The key is to move around as often as you can. "People have become so indoctrinated to calories and reps, but the real focus needs to be on reducing overall sedentary time," says Marc Hamilton, Ph.D., of the Pennington Biomedical Research Center in Baton Rouge, Louisiana.
Aim to do something NEAT for 10 minutes every waking hour. "Try standing every time you take a phone call or taking a 20-minute walk after dinner," says Levine. In fact, if there's one time you should get NEAT, it's when your belly's full. Even just 10 minutes of post-meal dishwashing can help obliterate many of sitting disease's ugly effects—and potentially add back years to your life.
Get-Moving Moves to Prevent Sitting Disease