Jill Filipovic is a journalist based in New York and Nairobi, Kenya, and the author of the book " The H-Spot: The Feminist Pursuit of Happiness ." Follow her on Twitter . The opinions expressed in this commentary are solely those of the author.

According to a new study , sitting for long periods correlates with earlier death; the longer you sit, the shorter your life.

What should you be doing? Some standing movement every 30 minutes, researchers say, is a must -- at least 2½ hours of moderate-intensity aerobic activity every week, and minimum twice-weekly strength training. For every half-hour you're on your butt, do five minutes of more vigorous cardiovascular exercise, like walking at a clip.

If only.

For most Americans, sedentariness is less a lifestyle choice than a financial and structural one. Many of our jobs require sitting, often in front of computers, for long periods, whether you're a lawyer or work in a call center. And we are vastly overworked , with nearly 30% of legal and management-level employees working more than 45 hours per week, according to a study last year by the Washington Center for Equitable Growth.

Things are even worse for low-wage workers. Inconsistent hours can mean underwork, but even that can be anathema to exercise, as it prevents them from planning (not to mention adds significant stress).

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As we sink even deeper into the information economy, changing these workplace norms becomes even more urgent. That means action not just from employers and the private sector, but the government. The status quo is simply too deadly to ignore.

How did we get to this point of our work habits becoming an actual threat to our health? The details are sobering (maybe you better sit down for this).

First, the way we get ourselves to these sit-down jobs: Overwhelmingly on our butts. Some 86% of us (!) drive to work, says a US Census report on commuting habits. Only about 5% of us take public transportation, just over 2% walk, and less than 1% bike.

This isn't necessarily because we're lazy, we just don't have a choice. American public transportation is notoriously subpar, with many of America's large cities lacking the kind of affordable, well-connected network of trams, buses and under- and above-ground trains that are a hallmark of nearly every major western European city. And if you're outside the city looking for public transportation, you're out of luck.

Of course, there are lifestyle choices as well: American adults watch an average of five hours of television every day, and it seems unlikely we're mostly on a treadmill while we're doing it. More than 80% of us don't exercise as much as is recommended.

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Yes, some of that is sheer indolence, but a lot more of it comes from the lack of support we receive, especially when it comes to working and living the rest of our lives. If you're a salaried worker toiling for 50 hours a week, is it any wonder you don't want to spend five minutes of every 30 going for a brisk walk -- one that's going to add up to getting home even later?

And if you're a low-income wage worker — as is half of America's workforce -- life can feel like a constant state of cobbling a million different pieces together: Getting your hours for the week, then figuring out child care according to an always-changing schedule, then calculating if the hours are going to be enough to make rent and pay the electric bill, then figuring out how to supplement your paltry income, then adding time by commuting via bad public transport, and on and on.

Throw in a sick kid or a parent who falls and breaks a bone, and the whole thing unravels. (I'm not seeing where a five minute walk every hour fits in.) It's exhausting to think about it and it's a safe bet your employer doesn't.

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The fact is, exercise is energizing, our human bodies have evolved to do it — they need it -- and the more you do it, the more you want to do it. Lethargy has the opposite effect -- the more you sit, the harder it is to get up and go.

But the entire framework of modern American life is built to incentivize lethargy, from employers to infrastructure to public policy.

Bottom line? The way we work and commute is a public health issue, and one both the private sector and our city, state and federal governments should be working to fix.

The solutions aren't mysterious. If employers want healthier and more engaged employees, here's what they can do: cap working hours, encourage work-from-home days, include gym memberships in the company insurance plan, and create an office culture where getting up and walking around is promoted, not looked on as a kind of malingering.

And if our political leaders really want a healthy, productive American population, as they say they do, they need to invest in better public transport, as well as good sidewalks and safe bike lanes. This should all be front and center in the restoration of America's crumbling infrastructure.

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Employers have, throughout history, proven themselves to be exploitative when given the opportunity, and so it's up to the government to regulate overwork, and to require that employees be treated like human beings -- given consistent work hours, paid sick days, paid family leave, and vacation.

Of course some of us will still walk from our beds to the garage, the parking lot to work, and then the garage back to our couches where we flop and watch TV all night. But without the immense and unnecessary stress currently put on workers from the very bottom up to the near-top, and provided with the tools to enable more physical activity and more time to simply be human, we would see a lot of Americans living better -- and living longer.