Scientists have known for some time that sitting down for hours each day isn’t very good for your health in the long term. But a recent review of 47 studies that looked at the health effects of sitting has found that sitting all day long can have negative health effects for everyone — even the 20 percent of Americans who get their recommended 150 minutes of exercise per week.
The review, published in the Annals of Internal Medicine, found that the more sedentary a person is, the higher his or her risk for Type 2 diabetes, heart disease, cancer, and shortened lifespan. While exercising can still reduce your risk of serious illness and early death, it cannot completely balance out the ill health effects of sitting for hours a day. The review has some limitations, however. Chiefly, it fails to establish a limit beyond which sitting becomes unsafe. It also fails to clarify whether interrupting long periods of sitting with exercise breaks helps to offset the ill effects of sitting, and if so, by how much.
How Harmful Is Sitting?
According to research published in the Journal of the National Cancer Institute last year, you raise your risk of colon cancer by eight percent for every two hours you spend sitting at your desk or on the couch. That same amount of time spent sitting raises your risk of lung cancer by six percent, and your risk of endometrial cancer by 10 percent. Your body burns fewer calories when you sit, and releases fewer fat-burning enzymes. Sitting also contributes to insulin resistance, a key factor in the development of Type 2 diabetes.
The 47-study review found that people who sit for eight to nine hours a day are at the highest risk for cardiovascular disease, Type 2 diabetes, and cancer. Sitting all day raises your risk of cardiovascular disease by 14 percent and your risk of cancer by 13 percent, the review found. Because sitting raises insulin resistance, sitting for eight to nine hours a day can supposedly increase your risk of developing Type 2 diabetes to skyrocket by an astounding 91 percent.
The review found that exercising for 30 to 60 minutes a day does not completely cancel out the negative health effects of sitting down all day long. But those who didn’t exercise were found to have the highest risk of premature death — they were 40 percent more likely to die young. Those who exercised regularly were about 10 percent more likely to die young. The risk of early death among exercisers who sit for long periods is about 16 percent higherthan among those who exercise and also spend most of their working day on their feet.
How Much Sitting Is Too Much?
Unfortunately, the 47-study review did not establish any clear guidelines for how much sitting is too much. That’s because the 47 studies involved in the review did not use any standardized guidelines for what constitutes “prolonged sitting” or, for that matter, what constitutes high activity levels. Researchers in one of the studies included participants who sat for as brief a time as an hour a day in the “prolonged sitting” group, while other studies defined “prolonged sitting” as being seated for at least five or six hours each day.
In at least one study, participants in the “prolonged sitting” group logged more than 11 hours a day in their chairs. Likewise, the studies defined activity levels differently. Activity levels among study participants ranged from just 20 minutes per day for participants in some studies, to seven hours a week or more among others.
Since most Americans spend more than 50 percent of their waking hours sitting at a desk, on a couch, or in a car, it’s probably safe to say that most people in the United States sit too much. And since a mere 20 percent of Americans get enough exercise each week to meet CDC recommendations, it’s probably also safe to say that, for most, the risk of early death from sitting hovers closer to 40 percent than to 10 percent. Of course, even if you do sit at a desk all day, regular exercise can still do a lot to improve your health and extend your life. You can do even more for your health by seeing your doctor regularly and taking any medications you’re prescribed as directed. Save money on your prescriptions at CanadaDrugPharmacy.com.
So, can you undo the health effects of sitting too much? While not everyone can work at a standing desk, there’s still a lot you can do to cut down on your daily sitting time. Senior author of the research review, Dr. David Alter, recommends:
- Getting up to move around for a few minutes every half hour while working at a desk.
- Standing or doing exercises during commercial breaks while watching TV.
- Exercising for 30 to 60 minutes a day.
- Reduce sitting time by 15 to 20 minutes a day, with the ultimate goal of sitting for two to three hours less each day after a few weeks.
It may be helpful to wear an activity tracker to help you monitor and reduce your sedentary hours each day. The more time you can spend on your feet and moving around, the less time you’ll spend sitting — and the longer you’ll live in good health.