Exercise — not standing — protects against the harms of a sedentary lifestyle

You may have heard the warning that sitting is the new smoking — that our sedentary lifestyles are a huge health threat and we could die an early death if we sit, tethered to our computers and our TVs, for too many hours each day.

But it’s not just the sitting that health experts are worried about; it’s our general lack of any physical activity. In a new paper, published in the journal JAMA, researchers at the Centers for Disease Control and Prevention looked at both how much we sit and how much we exercise — and they came to a painful, though predictable, conclusion: We’re not moving nearly enough.

They estimated that one in four adults sit for more than eight hours a day. That means most of our waking hours are spent sitting on our butts.

The data came from a nationally representative survey of 5,900 adults in the 2015-’16 National Health and Nutrition Examination Survey, where people were also asked how much exercise they get. Four in 10 Americans reported being physically inactive, meaning they get no moderate or vigorous exercise each week. And recall that the CDC recommends at least two hours and 30 minutes of moderate-intensity exercise every week, or 75 minutes of vigorous working out.

Unfortunately, though standing desks have been heavily promoted as the antidote to our sedentary lifestyle, their benefits have been grossly oversold. Standing doesn’t count as exercise, and, unlike running or cycling, there is there is no evidence that simply standing at work improves cardiovascular health.

In fact, the latest science suggests a lack of exercise, not sitting at work, might be the bigger health problem overall.

The problem with the evidence on sitting and health

The sit-and-die public health messages are based on a bunch of studies that have correlated sitting too much with a premature death and a higher risk of chronic diseases including cancer, diabetes, and heart disease.

But the link between sitting and death has been complicated in recent years. And it turns out the context may matter more than the sitting itself. Here’s Emmanuel Stamatakis, an associate professor at the University of Sydney, over at the Conversation:

… sitting down at work isn’t strongly linked with long-term health risks. Perhaps that’s because higher status jobs involve more sitting, and higher socioeconomic position is linked with a lower risk of chronic disease.

It’s a different case for sitting watching TV, the type of sitting most consistently linked with long-term health risks such as type 2 diabetes, heart disease and an early death.

People who watch a lot of TV tend to be of lower socioeconomic status, unemployed, have poorer mental health, eat unhealthy foods and be exposed to unhealthy food advertising.

In other words, the literature on sitting is likely confounded by these socioeconomic factors that may help explain why some sedentary people have worse health outcomes than other sedentary people.

The same kind of counterintuitive finding pops up in the research on people who stand a lot for work. As Aaron Carroll explained in the New York Times this week, a large, long-term study of 38,000 people found that those who stand or walk for more than six hours each day while working had at least double the risk of surgery for varicose veins, which are associated with a greater risk of arterial disease and heart failure.

So standing at work — just like sitting and watching too much TV — “could be a marker for other unhealthy demographic factors or habits, including lower socioeconomic status,” he added.

Exercise — not standing — protects against the potential harms of a sedentary lifestyle

Getty Images/Hero Images

There is one thing that protects against the potential ravages of a sedentary lifestyle: exercise. As Stamatakis explained, being physically inactive — not just sitting a lot — is what appears to heighten the risk of chronic disease. And researchers have found that the health harms of sitting seem to go away when people get about an hour of physical activity each day.

Regular physical activity can “prevent dementia, type 2 diabetes, some cancers, depression, heart disease and other common serious conditions — reducing the risk of each by at least 30%,” according to this 2015 report on the benefits of exercise from the Academy of Medical Royal Colleges. “This is better than many drugs.”

It also helps people live longer. “Many studies give an approximate 30% risk reduction in all-cause mortality. Smoking is the biggest contributor to early mortality and years living with chronic illness and disability.” Overall, the researchers found, regular exercise reduces cardiac death by 31 percent.

And right now, Americans aren’t getting enough. The new survey found four in 10 Americans reported being completely physically inactive each week, meaning they get no moderate or vigorous exercise.

Getting more exercise doesn’t necessarily require extra time

Americans often complain that they don’t have enough time to work out. A 2015 survey asked a group of 1,000 of them how they’d spend an extra four hours each week if they suddenly had the time. The No. 1 answer? Exercise. The desire for more time to work out trumped the wish for more time spent with family, sleeping, or even doing hobbies.

But this 2017 Lancet paper demonstrated that all kinds of physical activity were equally good for the heart. And it’s a reminder that we often overthink exercise — and we may not actually need to set aside extra time to work out.

Exercise doesn’t require a gym membership or fancy shoes. Exercise is something you can do throughout the day, every day. It also doesn’t need to be grueling, and it doesn’t have to cost anything, to see health benefits.

Simply walking more — while commuting, running errands, in a meeting, or on the phone — counts for a lot.

The researchers in the Lancet study also found there was a linear relationship between the amount of exercise and disease risk, meaning the more hours a person spent doing physical activity (again, of any kind), the lower their risk of disease and death. (The benefits seemed to taper off at 1.8 hours of brisk walking per day.) And the people who reported getting the most physical activity were the ones who had exercise built into their daily lives, through simple things like active transport to work, their jobs, or housework. Note: They weren’t just standing around at their desks.

Source link

Leave a Reply