New Research: Three Hours Of Sitting Will Damage Your Blood Vessels
Increasing research has highlighted the significant risk of excessive sitting for adults, but “grown-ups” are not the only ones at risk. Children spend more than 60 percent of their waking day sedentary,1 and by some estimates children sit an average of 8.5 hours a day.2
Further, activity levels are thought to decline steeply after age 8, especially among girls.3 Researchers decided to study a small group of girls (aged 7 to 10 years) to determine if sitting is as detrimental to their health as it appears to be to adults.
In adults, sitting for hours leads to constricted arteries in your legs, which impedes blood flow, raises blood pressure, and contributes to the development of heart disease over time.4 Does the same hold true among children?
At the start of the study, all of the girls had healthy arterial function. However, after sitting for three hours, playing on tablets or watching movies, there was a “profound” reduction in vascular function.5
There were some encouraging findings. The girls’ artery function had returned to normal a few days later when they returned to the lab. And when the sitting time was interrupted by a gentle 10-minute cycling session, no decline in vascular function was recorded.
On average, a US adult spends nine to 10 hours each day sitting,9 which is so much inactivity that even a 30- or 60-minute workout can’t counteract its effects.
While it might seem natural to sit this long, since you’ve probably grown used to it (physically and mentally), it’s actually quite contrary to nature.
Studies looking at life in agriculture environments show that people in agrarian villages sit for about three hours a day. Your body is made to move around and be active the majority of the day, and significant negative changes occur when you spend the majority of the day sedentary instead.
Pancreas: Your body’s ability to respond to insulin responds after just one day of excess sitting, which leads your pancreas to produce increased amounts. 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.
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.
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 also increase your risk of herniated disks.
Frequent fidgeting, restlessness, or squirming are often used to describe symptoms of attention-deficit hyperactivity disorder (ADHD) in children. But many would argue that such behaviors are natural when children are forced to “sit still” for unnaturally long periods of time – like the majority of a school day.
To combat this problem, some forward-thinking schools are giving children more opportunity to move around throughout the day, rather than expecting them to sit for hours in desks. For instance, at Vallecito Elementary School in San Rafael, California, at least four classes have introduced chair-less standing desks.17
After an initial adjustment period, the standing desks have been met with rave reviews. The students report the desks are “fun” and help them feel “more focused.” Teachers say the desks make children more attentive and parents say their kids are sleeping better at night… all while avoiding the risks of excessive sitting time; a win-win situation all around! Similarly, Naperville Central High School in Illinois implemented a special program where students could take part in a dynamic gym class at the beginning of the day and had access to exercise bikes and balls throughout the day in their classrooms.
Those who participated nearly doubled their reading scores and math scores increased 20-fold. The results speak for themselves… and they extend to adults, too. If you work in an office environment, converting your workstation to a standing desk is one of the best ways to cut back on your sitting time.
A study published in the journal Preventive Medicine analyzed 23 active desk studies and found they reduced sedentary time and improved mood. Additional benefits from from standing desks included:
As you cut back on sitting, the point is not to simply stand still instead. Fortunately, as you stand up, you’ll likely naturally move as well. According to Dr. James Levine, author of the book Get Up!: Why Your Chair Is Killing You and What You Can Do About It:
Even movements such as fidgeting appear beneficial. Among women who reported sitting for seven hours or more a day and hardly fidgeting, the risk of all-cause mortality increased by 30 percent. Women who reported fidgeting often fared far better – after sitting for five to six hours a day, their risk of mortality decreased. Further, there was no increased mortality risk from longer sitting time in either the “middle” or “high” fidgeting groups.
Another example, people who made a point to get up and walk around for two minutes out of every hour increased their lifespan by 33 percent compared to those who did not.22 Those who stood up for two minutes an hour did not reap the benefits that those who walked for two minutes did. Setting a goal of 7,000 to 10,000 steps a day (which is just over three to five miles, or 6 to 9 kilometers) can go a long way toward getting more movement and less sitting into your life. This should be over and above any exercise regimen you may have.
I personally am doing about 14,000 to 15,000 steps a day, which I can typically accomplish with a 90-minute walk. Tracking your steps can also show you how simple and seemingly minor changes to the way you move around at work can add up. I recommend using a pedometer, or better yet, one of the newer wearable fitness trackers to keep track of your daily steps. Other simple ways to increase your physical movement and avoid sitting down at work and elsewhere include:
It’s just as important for children and adolescents to remain active throughout the day as it is for adults. Younger kids tend to naturally want to be active, so be sure to encourage this movement and activity as much as possible. Unfortunately, as kids get older they may tend to become increasingly sedentary, especially if they have regular access to computers, TV, tablets, and video games.
The researchers of the featured study were actually surprised at how easy it was to get the young girls to stay seated for three hours; they had thought it was going to be a challenge to keep them still, but the girls were happy to oblige.
As a parent, you’ll want to set limits on your child’s “screen time” and encourage not only organized sports and other activities (like dance classes) but also regular active play and taking part in active chores around the house – walking the dog, taking out the trash, raking leaves, etc. If you have a school-aged child, you may want to speak with your child’s educators about ways to incorporate more movement into their hours spent at school. Outdoor playtime, standing desks, gym classes, and providing access to exercise bikes and exercise balls are just several examples.It’s also imperative that you act as a role model by staying active yourself. If your kids see you moving around often and sitting less, they will naturally follow suit
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By Dr. Mercola