Various studies have shown that long periods of sitting day in and day out can seriously affect your health and shorten your life. These findings put together by popular blog, Dr. Mercola, show the situation is far more serious than you perhaps thought The body is designed for regular movement, but many people spend the bulk of their day sitting still instead. Worse still, some people don’t fit in a workout or a long walk either, which means their bodies are virtually always in a sedentary state. It’s not that sitting is inherently dangerous… the danger is in the dose. What happens to your body when you sit for too long Dr. James Levine, co-director of the Mayo Clinic and the Arizona State University Obesity Initiative, and author of the book Get Up! Why Your Chair Is Killing You and What You Can Do About It, has dedicated a good part of his career to investigating the health effects of sitting. His investigations show that when you’ve been sitting for a long period of time and then get up, a number of molecular cascades occur. For example, within 90 seconds of standing up, the muscular and cellular systems that process blood sugar, triglycerides, and cholesterol—which are mediated by insulin—are activated. All of these molecular effects are activated simply by carrying your own bodyweight. These cellular mechanisms are also responsible for pushing fuel into your cells and, if done regularly, will radically decrease your risk of diabetes and obesity. In short, at the molecular level, your body was designed to be active and on the move all day long. When you stop moving for extended periods of time, it’s like telling your body it’s time to shut down and prepare for death. The Mind Unleashed featured a particularly noteworthy description of what happens in various areas of your body after prolonged sitting:
• Heart: When you sit, blood flows slower and muscles burn less fat,
which makes it easier for fatty acids to clog your heart. Research
published in the Journal of the American College of Cardiology, for
instance, showed that women who sit for 10 or more hours a day may
have a significantly greater risk of developing heart disease than
those who sit for five hours or less.
• Pancreas: Your body’s ability to respond to insulin is affected by
just one day of excess sitting, which leads your pancreas to produce
increased amounts of insulin, and this may lead to diabetes.
Research published in Diabetologia found that those who sat for the
longest periods of time were twice as likely to have diabetes or heart
disease, compared to those who sat the least. Sitting for more than
eight hours a day has also been associated with a 90 percent increased
risk of type 2 diabetes.
• Colon Cancer: Excess sitting may increase your risk of colon,
breast, and endometrial cancers. The mechanism isn’t known for
certain, but it could be due to excess insulin production, which
encourages cell growth, or the fact that regular movement boosts
antioxidants in your body that may eliminate potentially
cancer-causing free radicals.
Findings presented at the 2015 Inaugural Active Working Summit also
found that sitting increases:
– Lung cancer by 54 percent
– Uterine cancer by 66 percent
– Colon cancer by 30 percent
Another reason for this increased cancer risk is thought to be linked
to weight gain and associated biochemical changes, such as alterations
in hormones, metabolic dysfunction, leptin dysfunction, and
inflammation—all of which promote cancer.
Digestion: Sitting down after you’ve eaten causes your abdominal
contents to compress, slowing down digestion. Sluggish digestion, in
turn, can lead to cramping, bloating, heartburn, and constipation, as
well as dysbiosis in your gastrointestinal tract, a condition caused
by microbial imbalances in your body. According to Microbial Ecology
in Health and Disease:
“There is growing evidence that dysbiosis of the gut microbiota is
associated with the pathogenesis of both intestinal and
extra-intestinal disorders. Intestinal disorders include inflammatory
bowel disease, irritable bowel syndrome (IBS), and celiac disease,
while extra-intestinal disorders include allergy, asthma, metabolic
syndrome, cardiovascular disease, and obesity.”
• Your brain function slows when your body is sedentary for too long.
Your brain will get less fresh blood and oxygen, which are needed to
trigger the release of brain- and mood-enhancing chemicals.
• Strained Neck and Shoulders: It’s common to hold your neck and head
forward while working at a computer or cradling a phone to your ear.
This can lead to strains to your cervical vertebrae along with
permanent imbalances, which can lead to neck strain, sore shoulders
• Back Problems: Sitting puts more pressure on your spine than
standing, and the toll on your back health is even worse if you’re
sitting hunched in front of a computer. It’s estimated that 40 percent
of people with back pain have spent long hours at their computer each
The disks in your back are meant to expand and contract as you move,
which allows them to absorb blood and nutrients. When you sit, the
disks are compressed and can lose flexibility over time. Sitting
excessively can also increase your risk of herniated disks.
Personally, after I reduced my normal 12 to 14 hours of daily sitting
to under one hour, the back pain I’d struggled with for decades
Standing requires you to tense your abdominal muscles, which go unused
when you sit, ultimately leading to weak abdominals.
Hip Problems: Your hips also suffer from prolonged sitting, becoming
tight and limited in range of motion because they are rarely extended.
In the elderly, decreased hip mobility is a leading cause of falls.
Sitting also does nothing for your glutes, which may become weakened,
affecting your stability and the power of your stride when walking and
• Varicose Veins: Sitting leads to poor circulation in your legs,
which can cause swelling in your ankles, varicose veins, and blood
clots known as deep vein thrombosis (DVT).
• Weak Bones: Walking, running, and engaging in other weight-bearing
activities lead to stronger, denser bones. Lack of activity may cause
weak bones and even osteoporosis.
Too much sitting can take years off your life
The more hours you spend sitting in a day, the shorter your lifespan
may be. One study found, for instance, that reducing the average time
you spend sitting down to less than three hours a day could increase
your life expectancy by two years.
Another study, published in the British Journal of Sports Medicine,
concluded that each hour spent watching television after the age of 25
reduces your life expectancy by nearly 22 minutes. To put this into
perspective, the authors compared it to smoking – each cigarette
reduces your life expectancy by about 11 minutes. All in all, the
researchers found that adults who spend an average of six hours in
front of the TV will reduce their life expectancy by just under 5
years, compared to someone who does not watch TV. Obesity Panacea made
a good point in its report on this study:
“These sorts of theoretical studies obviously need to be taken with a
large dollop of salt (just like the recent Australian study which
estimated that every hour of TV viewing shortens your life by 25
minutes). The point is simply that there is a non-negligible impact of
sitting/TV viewing on mortality, and given the extremely high
prevalence of these behaviors at the population level, they can have
noticeable impact on the lifespan of the population as a whole.”
How to Sit Smarter
The evidence is overwhelming at this point—10,000 studies and
growing—that prolonged sitting will reduce your lifespan by promoting
dozens of chronic diseases, even if you exercise regularly. I’ve
previously recommended standing up and doing exercises at your desk
every 10-15 minutes to counteract the ill effects of sitting, but
after reading Dr. Levine’s book, I’m convinced even that may be
insufficient if you’re seeking optimal health. I really think the
answer is to stand up as much as possible.
That said, sitting is sometimes necessary, so when you do sit
following the recommendations by “posture guru” Esther Gokhale can go
a long way toward improving posture-related pain associated with
prolonged sitting, and will likely help ameliorate the worst risks of
sitting. The basics of healthy sitting include the following points:
• Stack sitting: In order to allow the bones in your spine to stack
well and permit the muscles alongside them to relax, sit with your
behind sticking out behind you, but not exaggeratedly so. Now, when
you breathe, each in-and-out breath will automatically lengthen and
settle your spine.
This gentle movement stimulates circulation and allows natural healing
to go on even while you sit. While conventional advice tells you to
tuck in your pelvis to maintain an S-shaped spine, Esther has found
that a J-spine is far more natural. A J-spine refers to a posture
where your back is straight, your lumbar relatively flat, and your
buttocks are protruding slightly. By tucking your pelvis, you lose
about a third of the volume in your pelvic cavity, which squishes your
internal organs. This can compromise any number of them in a variety
This is further compounded if you’re both “tucked” and “hunched” while
sitting. This biomechanically correct posture allows you to move
freely, discourages pain, and allows your digestive organs to function
without restrictions or blockages.
• Stretch sitting. Another way to elongate your spine is by using your
backrest as a traction device. This simple maneuver brings your back
away from the backrest, lengthens your spine, and then roots you
higher up against the backrest.
This position helps you maintain an elongated spine, and by getting
traction on your discs, you allow them to rehydrate and prevent the
nerves from being impinged between your vertebrae. It will also help
flatten out your lumbar area, and this alone can sometimes provide
immediate pain relief if you have sciatic nerve root pain.
Remember, however, that for optimal health sitting should be your last
resort when you have no alternative. It is far better for you to stand
than sit. It might take a bit to adjust but once you do it will be
every bit as comfortable as sitting. As noted by Dr. Levine, while we
clearly need to rest from time to time, that rest is supposed to break
up activity—not the other way around. Inactivity—sitting—is not
supposed to be a way of life.