Why you are probably sitting down for too long

For most of us, sitting is a part of everyday life: at the office, on the move, at home… However, prolonged sitting, coupled with impaired vascular function, increases the risk of serious health conditions such as cardiovascular disease and type 2 diabetes.

In 1953, epidemiologist Jeremy Morris discovered that a London bus driver More than twice as likely Bus drivers are at high risk of developing coronary artery disease.

Given that the two groups of workers are demographically similar (in terms of age, gender, and income range), why were there such stark differences?

Morris’ answer was that bus drivers have to stand up and regularly climb the stairs of London’s iconic double-decker buses when selling tickets to passengers, whereas drivers remain seated for long periods of time. His groundbreaking research Laid the foundations A study on the association between physical activity and coronary artery health.

London bus drivers Now a thing of the pastMorris’ findings are more relevant than ever. Since the COVID-19 pandemic, there has been a massive shift to working from home. Increase the amount of time spent sitting togetherIt’s easy to sit at a desk for hours without getting up, without having to go to the water cooler or run from conference room to conference room. (But office culture had changed our work lives so much by the 1980s that some researchers We humans Homo sedens – “The Seated Man” – not Homo sapiens.

Why does sedentary behavior increase the risk of cardiovascular disease? The main hypothesis is Increased vascular dysfunction, Especially the legsThe vascular system is responsible for circulating blood and lymphatic fluids, which form part of the immune system.

David DunstanA physiologist at the Physical Activity and Nutrition Institute at Deakin University in Melbourne, Australia, he has extensively studied the effects of prolonged sitting and possible interventions.

“Sitting is characterised by reduced muscle activity,” Dunstan says. “When you’re sitting in a chair, the chair takes over all the responsibility.”

The combined effects of reduced muscle activity, reduced metabolic demand, and gravity Reduce peripheral blood flow This causes blood to pool in the leg muscles, resulting in blood pooling in the calf muscles. The biomechanics of sittingKeeping your legs bent for a long time can reduce blood flow.

However, when blood flow is reduced, shear stress decreases and endothelial cells Produces vasoconstrictors Substances that narrow blood vessels, such as endothelin 1, are secreted. In a vicious circle, blood flow is further reduced by vasoconstriction, and blood pressure rises to maintain blood flow. High blood pressure, or High blood pressureis one of the main risk factors for cardiovascular disease.

“it is [vascular dysfunction] “This is one potential mechanism,” Dunstan says, “but the reality is that we haven’t identified the exact mechanism, and there may be multiple mechanisms.”

Dunstan, who specializes in research into type 2 diabetes, also noted that a lack of exercise before or after meals can lead to an increase in diabetes. Increased blood sugar and insulin levelsBoth reduced insulin sensitivity and impaired vascular function increase the risk of cardiovascular disease and type 2 diabetes.

Given these well-known potential consequences, why do we sit for long periods of time, and can we break the habit?

“I think people are becoming more sedentary because society encourages it.”

Benjamin Gardner, a social psychologist specializing in habitual behaviors at the University of Surrey, has studied why people sit for long periods of time. “It’s not that anyone is doing it on purpose. It’s just that as things become more efficient, we don’t need to move around as much.”

“We encouraged people to try this. [standing up] “I interviewed them at three different meetings after each to see how they were doing, and what I found was interesting,” Gardner says. “In formal meetings, standing didn’t feel appropriate.”

Wearable technology may help move us to action. Promising New ResearchThe wearable device, called an accelerometer, provided 24-hour data on an individual’s behavioral patterns, such as sitting, standing, sleeping, and exercise. As Dunstan noted, this could potentially allow people to customize their sitting and standing times to suit them, and the device would automatically send reminders if they had been sitting for too long. But using the technology is not without its drawbacks: get annoyed Or become desensitized to the prompts.

For many, sedentary behaviour may seem like an inevitable consequence of modern life and work, but making small changes to your daily routine, like stretching more, fidgeting or standing up to make a cup of tea, can help break the habit.

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