The connection between sitting and diabetes

The Connection between Sitting and Diabetes

An estimated 422 million people worldwide are affected by diabetes, with the global prevalence of the disease growing exponentially between 1980 and 2014 (from 4.7% to 8.5% of the global population). In 2015 alone, an estimated 1.6 million deaths were directly caused by diabetes. That’s equivalent to the entire country of Bahrain succumbing to the complications of the disease in a single year. Germany is already spending almost 20% on all healthcare related expenditures on the treatment of Diabetes type II.

Funding for that from 2030 onwards is not secured at all and the demographic development, certainly not only in Germany will cause an unpredecented financial crisis of our health care system. Does it need to come that far? Diabetes Type II is one of the deadliest, most expensive diseases at all, since it leads to a number of serious complications, yet it is almost entirely avoidable by making the right lifestyle choices and one of them is to stop sitting for extended periods of time.

HOW SITTING INCREASES THE RISK OF DIABETES

Inactivity and sedentariness are the greatest risk factors for developing diabetes. Even somebody with an unfavourable dietary pattern might be able to get away with it, but it doesn’t work the other way around. In most cases, the combination of a poor diet with a job that includes long hours seated create the perfect metabolic storm.

Data from a large Brazilian study supports this idea. Researchers looked at over 60,000 men and women and found that watching television for more than four hours a day was associated with a 64% higher incidence of type 2 diabetes in men and a whopping 96% higher incidence of heart disease, with only slightly less dramatic numbers for women (Werneck et al., 2018).

Why is being sedentary such a big deal for diabetes? Physical activity improves how our cells respond to insulin which, in turn, improves our body’s ability to regulate blood glucose. Physical activity also supports better blood lipids, blood pressure and activity of the fat-burning enzyme lipoprotein lipase, which is key to understanding the implications of sitting and the rise of diabetes (more on that shortly). Finally, physical activity also helps with stress management and weight management, which is important because these are two known risk factors for diabetes in their own right.

Experimental studies have shown that prolonged sitting, with a respective reduction in the contraction of the large leg muscles, suppresses insulin activity and the activity of muscle lipoprotein lipase (LPL). LPL is an enzyme found primarily on the surface of cells that line tiny blood vessels in muscles and fatty tissue, and is essential for the breakdown of triglycerides (a form of fat) for use as energy. This is why muscle LPL levels are typically higher in athletes, as they need the LPL to replenish the muscle energy stores after exercise (Seip et al., 1998).

When muscle LPL activity is low, triglycerides are either stored in fat cells or remain in the blood, as opposed to being used for energy. Higher circulating levels of triglycerides increase the risk of cardiovascular disease, while a higher percentage of body fat increases insulin resistance. People with lower muscle LPL activity and higher LPL activity in fatty tissue are more likely to gain weight, particularly unhealthy body fat, compared to people with greater LPL activity in muscles (Ferland et al., 2012). Even people who have low muscle LPL activity and high LPL activity in fatty tissue, but are not obese or even overweight, are at a higher risk of diabetes, cardiovascular disease and metabolic syndrome. This is because so-called ‘thin-outside-fat-inside’ people carry a higher amount of visceral fat around their organs in the abdomen, which increases insulin resistance as well as the production of inflammatory cytokines (Thomas et al., 2012).

Regular long lasting activities, such as walking or biking, are particularly effective in maintaining a high level of LPL activity in slow-twitch postural skeletal muscles, whereas higher intensity exercise, such as running or tennis, is important for LPL activity in fast-twitch glycolytic muscles. As we age, we typically see a reduction in LPL activity in skeletal muscle fibres. A comparable pattern of reduced LPL activity is also seen in sedentary people. Interestingly, even older adults who engage in endurance training have been found to have a better blood lipid profile than younger sedentary adults (Hamilton et al., 2001). This just goes to show that, regardless of your age, it’s not too late to start incorporating new habits that can dramatically change your health and wellbeing.

Studies show that muscle LPL activity increases with even light exercise, compared to when sitting (Hamilton et al., 2007), but will not persist after the activity ends. This underscores the notion that a human truly needs to be engaged in low intensity movement regularly throughout the day in order to maintain a healthy metabolism (Bey et al., 2003).

DIABETES — THE SILENT PANDEMIC

America is particularly hard hit by this disease. According to the American Diabetes Association (ADA) there are over 30 million children and adults living with diabetes in the United States (around 9.4% of the population), with 1.5 million new cases diagnosed each year. While this means that many are likely unaware of their condition, it also serves to normalise the disease, which may result in lowered action or accountability.

Countless individuals are living with undiagnosed diabetes or prediabetes which, if left untreated, will in most cases have serious health effects as the disease progresses. Indeed, diabetes is a leading cause of death and disability, and is listed as the underlying cause or contributing factor in over 250,000 deaths each year in America alone. However, the actual toll of diabetes is likely to be much higher, with recent research showing that, in up to 60% of cases, the death certificates for those with diabetes do not even mention the disease (source ADA).

AN ECONOMIC TSUNAMI

The economic cost of diabetes is staggering. So much so, that the Canadian Diabetes Association (CDA) published a report in 2009 calling diabetes an ‘Economic Tsunami.’ The CDA predicts that by 2020 a new person will be diagnosed with diabetes every hour of every day.

The economic cost associated with diabetes in the U.S. provides a forecast of what lies ahead for many economies in the decades to come. In the U.S., direct medical costs of treatment for diabetes amounted to $176 billion in 2010, with losses in productivity reaching another $69 billion. Worldwide, estimates from a recent systematic review put the direct annual cost of diabetes at around $827 billion (Seuring et al., 2015). The International Diabetes Federation (IDF) estimates that total global healthcare spending on diabetes has more than tripled between 2003 and 2013 (IDF, 2013).

In recent years, the prevalence of diabetes has been rising more rapidly in middle- and low-income countries, meaning that some of the poorest communities will be forced to address an unprecedented economic and societal burden. One study estimated that from 2011–2030, losses in gross domestic product (GDP) will total $1.7 trillion worldwide, with $800 billion of that shouldered by those in low- and middle-income brackets (Bloom et al., 2011). And all this for a disease that is largely preventable.

WHAT IS DIABETES AND HOW DOES IT DEVELOP?

Despite being a very common disease, there is still widespread confusion around what diabetes actually is, and perhaps even more confusion around the different types. Simply speaking, diabetes is a chronic condition resulting from the body’s inability to sufficiently produce or properly use insulin, the hormone that enables sugar to be transported into cells to produce energy.

There are two types of diabetes, as well as prediabetes, a condition where blood sugar is higher than normal but not yet high enough for a diagnosis. Having prediabetes increases the risk of developing diabetes itself, as well as the risk of cardiovascular disease and neuropathy.

Type 1 diabetes is an autoimmune disease that often arises in childhood. Type 2 diabetes, the most common form, can occur in children and adults and is typically related to lifestyle and diet.

Type 2 diabetes was previously referred to as ‘adult-onset diabetes’ (or non-insulin dependent diabetes, NIDDM), but poor diet and increasingly sedentary behaviour early in life means that millions of children will develop this ‘adult’ disease, and with it some serious health consequences. 

In addition to sitting for hours each day at school, children are more likely than ever before to eschew outdoor play and physical activity. Instead, most children now spend their free time watching television, playing video games, and using computers or smartphones while sitting. In North America, children and teenagers spend 40–60% of their waking hours engaged in some form of screen-time pursuits (Saunders et al., 2014). And they are becoming used to and dependant on these devices at ever earlier ages; today, it is all too common to see toddlers confidently maneuvering their parents’ smartphones.

All this sedentary behaviour, combined with poor diet and an increased risk of having had a mother with diabetes, dramatically increases a child’s risk of developing type 2 diabetes later in life, if not in childhood itself (WHO, 2016). Type 2 diabetes, the ‘adult’ disease of modern civilisation, is now seen in children as young as six years old (Diabetes UK, 2010).

The prevalence of type 2 diabetes is increasing around the world in children of all ethnicities. While it is strongly associated with obesity, this disease can also manifest in children who are of a normal weight and may be asymptomatic or only display mild symptoms, which can delay diagnosis and treatment thereby increasing the risk of serious health effects.

In type 2 diabetes, the pancreas may produce too little insulin, and the liver might overproduce glucose, resulting in elevated blood sugar. The main problem, though, is peripheral insulin resistance, particularly in muscle cells.

Our bodies need insulin to effectively use sugar as an energy source. When we do not have enough insulin, or when our cells become insulin-resistant, the sugar in our blood is unable to enter cells. This means that our blood sugar levels rise, and our cells are deprived of the fuel they need to function correctly. As a result, symptoms of diabetes can include unwanted weight loss, fatigue, slow and impaired healing and immune function, cognitive deficits, and a whole host of other issues resulting from a general diminishing of normal and healthy physiological processes.

THE COMPLICATIONS FROM DIABETES

When blood glucose levels remain elevated, the same glucose that fuels our cells and maintains energy production begins to act as toxin on the vessels, resulting in pathological changes in organs including the eyes, nerves, kidneys, brain and blood vessels, respectively. Poorly managed or untreated diabetes can consequently lead to cardiovascular disease, stroke, kidney failure, neuropathy, retinopathy, blindness and lower limb amputations.

The risk associated with diabetes for cardiovascular disease is profound. An individual with diabetes is at the same risk of cardiovascular disease as someone (without diabetes) who has previously suffered a heart attack. Diabetes also doubles the risk of stroke in the first five years following diagnosis, compared to the general population (Diabetes UK, 2010).

In the U.S., almost 40% of adults with diabetes will develop chronic kidney disease, and in 2014 over 50,000 people required dialysis after being diagnosed with end-stage kidney disease (WHO, 2016). Diabetes is the single most common cause of kidney failure, or end-stage renal disease, worldwide. Kidney disease accounts for 21% of deaths in type 1 diabetes and 11% of deaths in type 2 diabetes (Department of Health, 2007; Morrish et al., 2001).

It goes without saying that kidney disease can dramatically affect the quality of one’s life, necessitating the use of medications and regular dialysis. What’s more, having diabetes often means that the affected patient may be a poor candidate for a kidney transplant, due to an increased risk of infection and other complications.

Another real threat is the risk of losing one’s eyesight, as diabetes is a leading cause of blindness (Diabetes UK, 2010; CDA, 2009). Persistently elevated blood sugar levels leads to damage in the retina, optic nerve and blood vessels. Within 20 years of being diagnosed, 60% of people with type 2 diabetes will have some degree of retinopathy (Scanlon, 2008). Diabetes also doubles the risk of other debilitating eye diseases, such as cataracts and glaucoma (Petit & Adamec, 2002).

Given the host of associated ailments noted above, it’s not surprising that many diabetes patients also suffer from depression (CDA, 2009). This is likely due to a combination of the symptoms of the disease itself, difficulties posed by managing it (such as financial and familial burden) and biochemical factors (Kiecolt-Glaser, 2015).

Taken together, the average diabetes patient can expect to lose 10–20 years of their life expectancy. This fact alone shows just how important it is to take preventative steps to curb the risk for diabetes, which can be achieved with some simple lifestyle changes including diet and exercise.

PREVENTING AND REVERSING DIABETES

For people at risk, physical activity and modest weight loss have been shown to lower the risk of type 2 diabetes by up to 58%. The difficulty is, when your cells aren’t getting enough fuel it can feel like an impossible battle to go for even a quick run around the block.

Instead of focusing on the occasional bouts of intense exercise, the best way to prevent, delay or manage diabetes is simply to stop sitting and start walking. Taking a stroll after breakfast, lunch and dinner has been shown to prevent the postprandial (post-meal) spike in blood glucose, as well as lower blood pressure. Those after-meal blood sugar spikes pose a significant risk for cardiometabolic disease but can be greatly reduced by cutting back on sitting time. A walk immediately following a meal has been proven to contribute to a significant reduction in blood glucose. One study showed that blood glucose was decreased by nearly 50% when meals were followed by walking, both in healthy individuals as well as those with type 1 diabetes (Manohar et al., 2012). While true for everybody, people with diabetes or those who are at risk should carefully avoid prolonged sitting times and search for ways to incorporate more movement during the day. It could make all the difference in the world (Dempsey et al., 2018).

In an evolutionary context, the release of blood glucose as a response to a stressful stimuli makes complete sense, as this boost of fast available energy was often essential for survival. In today’s world, however, many of us have no physical release for stress in the workplace, meaning that stress caused by workload and looming deadlines is most likely dealt with while remaining seated. So, while the way we spend our days has changed dramatically over the past few thousand years, our bodies’ response to stress has not and release of the stress hormone cortisone still triggers the same elevation in blood glucose as it did in our prehistoric ancestors. Upon identifying a stressor, our bodies immediately flood with adrenaline and norepinephrine, which increases our heart rate and respiration, causes sweating, and gives us a surge of energy that allows us to focus our attention and flee from danger.

Cortisol takes a little bit longer to kick in (minutes versus seconds) because it requires a rather lengthy chain of actors in the brain and the kidneys to be activated before cortisol is released. Since the body is in rescue mode at this time, it will also temporarily silence all non-emergency systems, such as the reproductive system, digestive system, growth and immune functions. Most importantly, in the context of diabetes, storage of blood glucose in cells is not desirable in an emergency setting, which makes cortisol a very potent antagonist of insulin. While measures to counterbalance stress span a wide range of possibilities and are beyond the scope of this book, a simple reduction in sitting time will ensure that the available energy has a place to be used when it comes into play.

Perhaps the linchpin of reducing the risk of diabetes is weight management. The problem with being overweight is that it decreases insulin sensitivity itself, creating another vicious cycle with huge implications for health.

WHAT CAN BE DONE?

The explosion of knowledge in medicine and the life sciences makes this some of the most exciting times we could ever imagine living in. As a species, we can expect to profit profoundly from the iterative exploration of new frontiers in medicine for years to come. An ever-widening holistic and scientific backed understanding of human health has swept away otherwise established beliefs with unprecedented speed and power. But what is all the knowledge worth anyway, if the realities we have put in place around us, such as our workplaces still ignore these findings?

The massive amount of accumulating evidence that relates diabetes to inactivity and sedentariness and its very real and concerning health risks can no longer be ignored. Socioeconomic pressure, resulting from exploding healthcare costs of chronic diseases linked to extended sitting, will hopefully contribute to a faster implementation of countermeasures.

Should we be optimistic? I believe, we can. Thanks to immediate access to research data, rapid sharing through social media, and the resulting increase in public awareness, we will continue to see more profound changes fueled by growing pressure on policy makers. Inaction will simply no longer be an option, particularly once individuals link their own personal health with current political or corporate decisions. Our voting is often driven by our own experiences, and health issues related to sitting will continue to be felt by many.

Looking towards the next generation, Millennials already tend to favour work-life balance over career advancement or income, and personal health and mental wellbeing rank higher in life decision-making than ever before. Companies, cities, and nations as a whole will be driven to create better settings for their workforce and citizens, in which our fundamental health needs are best met.

What can we expect from continued technological advancement? The unparalleled success of wearables illustrates the appreciation and demand we have for assistance with everyday health related guidance and decision-making. Lasting habits are a result of availability, ease of use, and recognisable change. Wearables cater perfectly to these demands. The worldwide wearables market in 2017 reached 115.4 million units, up 10.3% from the 104.6 million units shipped in 2016. Walkolution has partnered with the leader in the wearables industry, GARMIN to bring our users the best and most accurate activity data. We can also expect to have affordable access to ever more advanced self-tracking technology in the near future, such as real time muscle blood perfusion and oxygen level measurement.

It can be easy to take this wealth of readily available and cost effective data for granted. Gaining so much information would have previously taken a dedicated research team. With this new collection of self-knowledge, we have the tools to re-shape our homes — and, in particular, our workplaces — to best align with our changing needs throughout the day. By receiving robust real time feedback right on our wrists, about how our current actions are affecting our health in a given moment, we simply don’t have to wait for the results of expensive studies to be analysed before being published years later. Instead, we can conduct our very own studies, draw our own conclusions, and even contribute to studies with the data stored in our tracking devices.

About the Author 

Eric SoehngenEric Soehngen, M.D., Ph.D. is a German physician and specialist in Internal Medicine. With his company Walkolution, he battles the negative health effects that sitting has on the human body. 

Walkolution develops ergonomically optimized treadmill desks, which help to bring more movement into the daily work routine in the office or home office.

Photo credit: Sharon McCutcheon

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