Why sitting down for long dey bad for your health

Sitting is something most people do well every day, at the office, on public transport, or at home.

But due to some vascular dysfunction, sitting in one place for a long time may increase the risk of serious health problems such as cardiovascular disease and type 2 diabetes.

In 1953, epidemiologist Jeremy Morris discovered that London bus drivers were more likely to develop coronary heart disease.

Demographically (age, gender, income range) the two groups of workers are similar, so why do we say we get such a big difference?

Morris answers that bus drivers’ work requires them to stand on their wide feet and climb the steps of London’s famous double-decker buses regularly as they sell tickets to passengers, while drivers sit for long periods of time.

In this study, we set the foundation for research into the links between physical activity and coronary artery health.

Although London bus drivers are not working as they once were, Morris’ findings are more important than ever.

Since the COVID-19 pandemic, we haven’t seen a major shift toward working from home, which will likely increase our collective sitting time.

Without the usual need to collect water from the cooler and carry it from meeting room to meeting room, it is easier for people to spend hours sitting at a desk without having to stand.

(But office culture didn’t really change our work lives, so much so that by the 1980s some researchers were joking that our species had become not Homo sibili—that is, “the sitting man”—but Homo sapiens.)

Prolonged sitting is a form of sedentary behavior, characterized by a significant decrease in energy expenditure in the sitting or lying position.

Typical sedentary behaviors including watching TV, gaming, driving, and office work.

Sedentary behaviors are associated with an increased risk of cardiovascular disease, type 2 diabetes and premature death, and time spent sitting in particular has been identified as an independent risk factor for a range of health conditions.

In 2020, the World Health Organization proposed measures to reduce sedentary behavior.

Prolonged sitting as a form of sedentary behavior refers to a significant decrease in energy expenditure when sitting or lying down. Typical sedentary behaviors include watching television, gaming, driving, and office work.

Sedentary behaviors are linked to an increased risk of cardiovascular disease, type 2 diabetes, and premature death, and the amount of time we spend sitting in particular can identify us as an independent risk factor for a range of health conditions.

In 2020, WHO proposes measures to reduce sedentary behaviour.

Since 2010, researchers have been keen to point out that sedentary behavior is a lack of physical activity. You exercise well every day, and yet you sit for a long time.

However, the risks of sedentary behavior are greater for those who do not exercise enough.

It can be said that sitting for long periods may lead to increased vascular dysfunction, especially in the legs.

According to scientists, the vascular system is responsible for keeping blood and lymph fluids – which are part of the immune system – moving through blood vessels.

David Dunstan, a physiologist at Deakin University’s Institute of Physical Activity and Nutrition, in Melbourne, Australia, has conducted extensive research into the effects of prolonged sitting and potential interventions.

“Sitting reduces muscle activity,” says Dunstan. “If you sit in a chair, the chair takes all the responsibility.”

The combined effect of decreased muscle activity, decreased metabolic demand, and gravitational forces results in decreased blood flow to the leg muscles, resulting in blood pooling in the leg.

The biomechanics of sitting, where the legs are usually bent, also reduce blood flow.

Researchers suggest that anyone who sits for 120-180 minutes in one place is not healthy.

Decreased muscle activity in the leg muscles reduces metabolic demand. Metabolic demand is the primary determinant of blood flow, so blood flow to the legs is also reduced. The biomechanics of sitting, with the legs bent, causes blood to pool in the calves—one study of 21 healthy young volunteers noted an increase in calf circumference of about 1 cm (0.4 in) over two hours. Disease also reduces blood flow.

Normal blood flow creates friction, known as arterial shear stress, against the endothelial cells that line the walls of blood vessels. The endothelial cells respond to the force and secrete vasodilators, such as adenosine, prostacyclin, and nitric oxide, which keep blood vessels adequately dilated and maintain the vascular system’s ability to regulate itself—what many people call homeostasis.

However, decreased blood flow reduces shear stress, and endothelial cells produce vasoconstrictors such as endothelin-1, which cause blood vessels to narrow. In this vicious cycle, vasoconstriction reduces blood flow, and blood pressure rises to keep blood moving. High blood pressure, or hypertension, is a major risk factor for cardiovascular disease.

who [vascular dysfunction] “It’s one possible mechanism,” Dunstan adds. “But the truth is we can’t pinpoint the exact mechanisms, and there could be multiple mechanisms as well.

Although the underlying mechanisms are hypothetical, recent studies support this theory. One study in 16 healthy young men found that sitting for three hours increased blood pooling in the legs, peripheral vascular resistance, diastolic blood pressure, and leg circumference. Another study found that blood pressure rose with the amount of time spent sitting uninterrupted. Researchers generally agree that sitting uninterrupted for 120 to 180 minutes may be the threshold for not spending too much time in one sitting position, but vascular dysfunction generally increases with the amount of time spent sitting.

Sitting for a long time after eating a high-fat meal is harmful.

The musculoskeletal system is also likely to be affected. Sitting for long periods contributes to decreased muscle strength, decreased bone density, and increased total visceral fat in adipose tissue.

In addition, sitting for long periods of time is associated with physical discomfort, psychological stress at work, and increased depression, which may even lead to pressure ulcers.

“Sedentary behavior increases after eating, or after eating, which causes blood glucose and insulin levels to rise,” says Dunstan, who also specializes in research into type 2 diabetes. Poor insulin sensitivity and poor blood vessel function also contribute to increased risk of cardiovascular disease and type 2 diabetes.

People become more sedentary because society encourages them to be so. As efficiency increases, we no longer need to move around as much. – Benjamin Gardner

With all these unknown potential consequences, why do we say we still sit for too long – and how do we break the habit?

“I feel like kids are becoming less active because of the humidity society encourages.”

Benjamin Gardner, a social psychologist who specialises in all sorts of habitual behaviours at the University of Surrey, is looking into why people sit for so long. “Nobody is deliberately pushing me,” he says. “Now we’re more efficient, we don’t have to move around as much.”

In 2018, Gardner and colleagues found that encouraging people to stand in meetings can present unique social obstacles.

“We encourage people to try this.” [standing up] “In three different meetings, and we interviewed them after each one to see how they were doing, the results were shocking to us,” says Gardner. “In one formal meeting, these people felt like they were saying they had one type of sand.”

Getting up often to take a light walk or climb some stairs is also helpful.

Wearable technology also helps remind us to move. According to a promising new study, wearable devices called accelerometers provide 24-hour data on individual behavior patterns including sitting, standing, sleeping, and exercising.

As Dunstan Benn noted earlier, these devices could allow for tailored optimal sitting and standing times, with the devices sending automatic reminders when you’ve been sitting for too long.

However, the use of technology is not without its drawbacks, as some people get frustrated because they cannot or do not receive messages.

Above all, Gardner and his colleagues encourage moving between sitting and standing positions more frequently.

The idea of ​​breaking up sedentary time by simply standing is simple, but it provides significant health benefits, especially for low-activity individuals.

For wheelchair users or people with mobility limitations, specific, adapted exercises are suitable.

For many people, it’s hard to avoid sedentary behaviors due to modern life and work. But even simple changes to your daily routine – like stretching more, moving around or standing up to make a cup of tea – can help you break the habit of sitting.