By Dr. Mercola
How many hours do you sit each day? If you're not sure, do a quick tally. For most people, cutting this number in half, or even in quarters, would go a long way toward improving their health.
Sit less, move more. It's a motto worth repeating, especially as research accumulates showing just how detrimental prolonged sitting is for your body.
Diabetes, obesity, heart disease, cancer and premature death are just some of the chronic conditions linked to sitting too much, and a new study hints at why: Being sedentary for long periods of time each day appears to accelerate aging at the cellular level.
Among close to 1,500 older women included in the study, those who sat the longest were, on average, eight years older, biologically speaking, than women who moved around more often.1
Too Much Sitting Makes You Age Faster
Your daily lifestyle makes a difference in how fast your cells age — what you eat, the quality of your sleep, whether or not you smoke and, the latest, how long you sit all play a role.
Researchers from the University of California, San Diego (UCSD) School of Medicine gave activity trackers to a group of 64- to 95-year-old women and questioned them about their activity. Those who sat for more than 10 hours a day and got less than 40 minutes of moderate-to-vigorous physical activity had shorter telomeres.
Telomeres are caps on the end of DNA strands that are sometimes compared to the plastic caps on the end of shoelaces; they help protect your chromosomes from fraying or sticking together, which would damage their genetic information.
Every time a cell divides, the telomeres get shorter, which is why they're used as a measure of biological aging. Eventually, the telomeres become so short that the cell can no longer divide and dies. For this reason, telomeres are also sometimes compared to a lit bomb fuse.2
In the women who sat for 10-plus hours a day, the telomere shortening was equivalent to about eight years of aging. In other words, too much sitting accelerated the aging process by about eight years. Short telomeres have also been linked with chronic diseases such as cancer, heart disease and diabetes.
"Our study found cells age faster with a sedentary lifestyle. Chronological age does not always match biological age," lead study author Aladdin Shadyab, Ph.D., UCSD School of Medicine, said in a news release.3
Interestingly, women who exercised for at least 30 minutes a day did not have shorter telomere length, even if they also sat for long periods, which suggests the exercise yielded anti-aging effects that may help counteract prolonged sitting.
This is in contrast to previous research, which has found exercise cannot undo the health damage caused by an otherwise sedentary lifestyle.
Every Hour You Sit Decreases Your Life Expectancy by 2 Hours
In 2016, I interviewed Kelly Starrett, who has a Ph.D. in physical therapy and is the author of "Deskbound: Standing Up to a Sitting World." In "Deskbound," Starrett quoted research from Dr. James Levine showing that for every hour you sit down, your life expectancy decreases by two hours.
For comparison, every cigarette smoked reduces life expectancy by 11 minutes, which explains why some are now calling sitting the new smoking. For all intents and purposes, prolonged sitting may actually be far worse for your health than smoking.
Starrett even mentioned a study that found office workers who smoked to be healthier than non-smokers simply because they got up every 30 minutes or so and walked outside to have a cigarette.4 "That activity was enough to be a considerable change in the function and health of the human being," he said.
Another study found that excessive sitting increases lung cancer risk by 54 percent, uterine cancer risk by 66 percent and colon cancer risk by 30 percent, with researchers noting:5
"Sedentary behavior contributes to an interrelated network of increased body fat, altered production of sex hormones, metabolic dysfunction, leptin, adiponectin and inflammation, encouraging cancer development."
Separate research, published in the American Journal of Preventive Medicine, further found that sitting for more than three hours a day causes 3.8 percent of all-cause deaths in the 54 countries surveyed.6
Cutting your sitting time to less than three hours a day could increase your life expectancy by 0.2 years, the researchers concluded. More than 60 percent of people globally spend more than three hours a day sitting.7
Have You Tried the Sitting-Rising Test?
There have long been indications that regular movement is linked to longevity, and the sitting-rising test is one such example. The more you move, the more your body stays flexible, strong and able to carry out your daily functions.
The more time you spend sedentary, on the other hand, the faster your muscles atrophy and functional movements, like rising from a seated position, become more challenging.
The sitting-rising test (SRT) involves a score of 0 to 5 for each movement (sitting and rising), with a combined 10 being the highest score, awarded for those who can sit and rise from the floor without any assistance from their hands or knees.
While appearing simple, it actually gauges a number of important factors, including your muscle strength, flexibility, balance and motor coordination, all of which are relevant to your functional capability and general fitness.
To perform the test, sit down on the floor and then get up, using as little assistance from your hands, knees or other body parts as possible. For each body part that you use for support, you'll lose one point from the possible top score of 10.
For instance, if you put one hand on the floor for support to sit down, then use a knee and a hand to help you get up, you'll "lose" three points for a combined score of 7. Research shows the numbers strongly correlate with your risk of death within the next six years.8 For each unit increase in SRT score, participants gained a 21 percent improvement in survival. Specifically:
- Those who scored 0 to 3 were 6.5 times more likely to die during the six-year-long study than those who scored 8 to 10
- Those who scored 3.5 to 5.5 were 3.8 times more likely to die
- Those who scored 6 to 7.5 were 1.8 times more likely to die
Ditching Your Desk May Be a Fountain of Youth
Taken together, the research is clear that sitting less is a simple, straightforward strategy to fight aging and chronic disease. If you work in an office environment, having access to a sit-stand desk is one of the most effective techniques to slash your sitting time.9 Research by Levine and colleagues showed that the installation of sit-stand desks reduced sitting time during a 40-hour workweek by eight hours and reduced sedentary time by 3.2 hours.10
Further, the participants enjoyed having the option of a sit-stand desk, which was also associated with increased sense of well-being and energy and decreased fatigue while having no impact on productivity.
If you don't have a standing desk, it's possible to fashion one out of a regular desk by propping up your computer on a box or an overturned wastebasket. If standing isn't an option, you can reap many similar benefits by getting up from your chair every 20 minutes and taking a two-minute walk.
For times when you do sit, "sit with skill," Starrett recommends. He advises sitting on your sit bones, engaging your legs and trying to look over the chair. When you're first starting out, divide your day into optional sitting and non-optional sitting. Don't worry about the times when you have to sit, but take stock of what they call "junk sitting" and try to whittle that down.
Trading Sitting for Active Movement Is Key
When you start to work toward slashing your sitting time, you want to replace it with different types of movements and postures, not simply standing still. Fortunately, when you're standing, you're unlikely to stand completely still, at least not for long. You'll likely stretch, lean, bend and pace. You may take your foot on and off a footstool or fidget.
You can also try to work in short exercise sessions, walking and foam rolling. And for times when you do sit, ditch your chair and try something different, like sitting cross-legged on the floor. This is a healthy position that improves the range of motion in your hips.
Children, too, can benefit from immensely from less sitting. As in adults, prolonged sitting in children is linked to poor health outcomes and even affects cognitive function. A study published in the Journal of Medicine and Sport revealed, for instance, that in first-grade boys, lower levels of physical activity and higher levels of sitting time were linked to poorer reading skills.11
Many U.S. kids also suffer from sitting-induced range-of-motion problems which, if not addressed, may increase their risk of injury and compromise their long-term athletic and movement abilities
Take It Slow When Reducing Your Sitting Time
It can feel overwhelming to think about giving up your chair, but it's not an all-or-nothing proposition. Rather than focusing on not sitting, think about ways to move more. You might pace while talking on the phone or check your morning emails while doing squats in front of your computer.
If you're used to sitting for six, eight or 10 hours a day, you shouldn't expect to switch entirely to a standing desk overnight. Starrett recommends first transitioning to a standing desk with a perching stool and sitting on that for 20 or 30 minutes, then gradually increasing your standing time. In addition, be sure your desk is adjusted to the proper height.
Many people also feel more comfortable having somewhere to put their foot while standing, such as a stepstool. Gradually, you'll get used to the idea of standing and will find that you don't automatically look for a chair the way you used to.
For Elderly Adults, Movement Is Also Key
Getting back to the featured study, which included older women, it was clear that those who moved more were not experiencing the accelerated aging felt by their more sedentary peers. Inactivity in the elderly can be caused by many factors, from health conditions to social isolation, so the first step is figuring out the reason for the lack of movement.
If it's simply a matter of habit, joining a new social group or starting a new active hobby, like gardening, water aerobics or volunteering to walk your neighbor's dog, can get you out of your rut. If you're chair-bound, seated exercises can also be very beneficial.
Many people, regardless of age, also find fitness trackers to be motivating and helpful for reaching increased movement goals. In one study of postmenopausal women, those who used a fitness tracker engaged in 38 more minutes of physical activity a week compared to women who carried a pedometer.12
"When you can see what your activity levels are, and you know that someone is checking them, there's accountability, and you're motivated to work harder because you want to comply," Linda Arslanian, director of rehabilitation services at Harvard-affiliated Brigham and Women's Hospital told the Harvard Health Letter.13
So, grab a fitness tracker, prop up your computer to standing height and get moving more often. For more information, Starrett has a YouTube channel called MobilityWOD, which stands for Workout of the Day. The interventions he suggests are not only powerful, they're also inexpensive — in most cases free. They can help you break free from many of the chronic diseases and orthopedic problems linked to prolonged sitting.