Tuesday, October 30, 2012

It’s not as hard as it sounds.

I like to think of myself as an active person. I run, I walk, I lift weights.

But the truth is, I spend only a small fraction of my waking hours doing things that I could call “exercise.” A lot of the time, both at work and at home, I’m just plain sitting—whether it’s in front of my computer, in a meeting, or on the couch. And more and more research now seems to be showing that all this sitting is hurting me.

Discouraging? At first, yes. But it turns out that improving my lifestyle may be easier than I thought.

My colleague Margarite got me started on this when she wrote about some research by Shuwen Ng and Barry Popkin showing the incredible worldwide decline in physical activity over the past 50 years. In the United States since 1965, the average person has lost 75 MET-hours of energy expenditure a week, which is about as much energy as it takes you to walk for 22 hours at a moderate pace.

No way can I make up for that with just a couple of runs and lifting weights twice a week.

At the same time, researchers are telling us that even if we exercise, sitting cuts years off our lives. That’s bad news for me and my office job.

So what can I do about this? First I rigged up the easiest standing desk ever: I took a box of old copies of Endeavors and put it on my desk. This happens to be exactly the right height for me to type on my laptop or prop up a clipboard to do some reading or editing.

(Seeing me standing there typing on a box drives the guy down the hall crazy—he brought me some random pieces of office furniture to see if one of them would do instead. But nothing is as perfect as my box.)

I use my standing “desk” for part of every work day, but honestly, I don’t have what it takes to just stand for hours and hours—not when I have the option of sitting down. That’s why I was encouraged to find two studies (here and here) that suggest that just getting up out of your chair, even if only briefly, reduces the negative effects of sitting.

The first study found that people who broke up their periods of sitting had lower BMIs, waist circumferences, triglycerides, and plasma glucose levels—independent of the total amount of time they spent sitting and how much they exercised. The second study demonstrated more strongly, by randomly assigning people to experimental groups, that getting up for 2 minutes every 20 minutes improves insulin sensitivity.

Just 2 minutes? I could do that.

So I’ve been trying it out for the past week. Both at work and at home, I get out of my chair every 20 minutes. Sometimes that means I switch to a more active task, and sometimes it means I just stand in front of my computer for 2 minutes, still immersed in whatever I’m doing and waiting to sit back down again.

Will this stop me from gaining weight, from dying earlier, or from getting the Type 2 diabetes that I have risk factors for? I don’t know for sure. But breaking up my stretches of sitting makes me feel great. It gives me more energy. I don’t get that “tired even though I’ve just been sitting” feeling at the end of a work day anymore. Standing up makes me happier and healthier right now, and that’s a much better motivator than anything it might do for me 20 or 30 years later.

I’m curious to see where this idea is going to go. It’s easy enough to say, “I’m going to stand up every 20 minutes” when you’re sitting in a room alone. But no one wants to be the weirdo who stands up during meetings, or who attracts the boss’s notice by seeming to be constantly getting up from their desk. (“Standing desk?” my editor asked as he walked by my box-desk one day. “Yup,” I said. He nodded his approval, and that was that.)

Not everyone has a workplace like mine. If the research keeps showing that we can improve our health by breaking up sedentary time, we’ll need to start changing our jobs and schools to make standing possible and socially acceptable. “Get more exercise” is a good message, but the research seems to be telling us that that isn’t enough anymore.

Who’s going to stand up for standing up?

—Susan Hardy
Wednesday, June 20, 2012

I never planned on buying a house in my twenties. Growing up, I watched how my parents struggled to move from renting to homeownership even at the peak of their careers in their fifties. If buying a house were such a difficult dream for them to achieve, I didn’t see how I could possibly do it as a much younger person with one income.

It didn’t help that just a couple of years after I graduated from college, the news was suddenly full of stories about people who should have lived within their means but didn’t, people who shouldn’t have bought houses but did anyway. Okay, I get the message. I’ll keep renting! I thought. I was prepared to put off homeownership for a long time—until I married, or, if I stayed single, until I was much older and better established.

Then I started doing research for my Endeavors article about the Center for Community Capital’s plan, outlined in a book called Regaining the Dream, to increase the rate of homeownership among middle- and low-income people. Homeowners don’t need to be rich, the Center researchers say. They just need a lender who wants to help them succeed and won’t approve them for way too much money, and they need a predictable (30-year, fixed) mortgage without punishing fees. People who have those two things seem to do well at paying back their loans.

As I read Regaining the Dream, I noticed that some of these borrowers sounded a lot like me. They didn’t make tons of money. Some of them were single. And yet, the data said they were keeping up with their mortgages just fine. The thought started to creep into my mind: Maybe I should get one of these mortgages, too.

Through the research I did for my article, I found a whole network I never knew existed of nonprofits that help people without a lot of money or great credit history get loans and learn the financial skills they need to succeed as homeowners. In my part of North Carolina, for example, there’s Self-Help, the community development lender the authors write about in Regaining the Dream.

In towns around the country where housing prices are high relative to income—Chapel Hill, for example—there are policies that support affordable housing by requiring developers to build a certain number of homes that are sold at lower than market rate. This makes it possible for people who work for some of a town’s important institutions—public schools, government, universities, hospitals—to afford to own homes in the same places where they’re employed.

Because I work in Chapel Hill, I visited the Community Home Trust, an Orange County nonprofit that’s responsible for selling a lot of Chapel Hill’s below-market-rate homes. The Home Trust teaches a home-buying class where I learned exactly what’s in a loan application, what makes up a credit score, and why I should get a survey done on a property before I bought it. (They were right—you definitely should get a survey! It saved me from having to deal with legal complications with a property later on.)

After looking at a few houses, I ended up buying a little cottage at market rate in neighboring Durham, which is where I grew up. But I’m a big fan now of affordable-housing programs and of the community development lenders who loan to people—disproportionately women and minorities—whom other lenders consider too risky. And I’m grateful for the researchers who showed that good lending practices, not high incomes, are the key to successful homeownership.

My loan officer, Nate, told me that not one of his clients has ever defaulted on a loan. When I wondered whether his luck could hold, he laughed. “They’d better not default, with how careful we are about approving people now!”

Thanks for your confidence, Nate. I’ll try my best not to break your streak!

—Susan Hardy
Monday, June 13, 2011

Place your bet: is the universe an apple, a Pringle, or a cookie?

As part of my long-term project to be a better science writer, lately I’ve been reading Brian Greene. You may know him as a prominent string theorist, or as the author of several popular books on cosmology. Or maybe just as “the eleven dimensions guy.”

I mainly know Brian Greene because my college roommate, Sarah, had a crush on him. Anyone who can win the hearts of college-aged women while discussing quantum physics in a PBS documentary must, I figured, know something about the right way to explain science.

So as I’m reading Greene, I’ve been trying to figure out what makes him such a good science writer. Some of it is what you’d expect: funny analogies, Simpsons references. But he also employs some tricks that absolutely crack me up. I’m paraphrasing here, but he says a lot of stuff like: You may have to read this part twice. It’s pretty difficult. Or: I know this material is boring, but don’t be tempted to skip ahead to the black holes. Or, when he’s talking about space-time geometry (this one’s a direct quote): “Feel free to go into skim mode if at any point this section gets too heavy.”

By the time I was halfway through The Fabric of the Cosmos, I was pretty impressed, both with Greene and with myself. He was explaining heavy physics, and I was understanding it! Gravity and acceleration are equivalent—check. A particle in one place can mysteriously affect a particle in another place without sending it any kind of signal—check. The shape of the universe might be like a video game—wait. What?

That’s right, Greene told me. A video game. It’s like we’re all characters moving across the screen of a flat universe, and if we go off the right side of the screen, we’ll reappear on the left. Or maybe the shape of the universe is more like a sphere. Or a Pringle.

A Pringle?!  Surely the universe couldn’t really be anything like snack food, or like a Pac-Man game. There’s gotta be more to this, I thought.

So I called up Laura Mersini-Houghton, a UNC theoretical physicist and cosmologist who’s spent a lot of time thinking about the shape of the universe. (Or the universes, plural. More on that later. But don’t skip ahead, okay?)

Mersini-Houghton never talks about Pringles, which makes this easier for me. Instead, she describes one of the possible universe-shapes as a hyperbola growing with time. If that seems like a crazy shape for the universe to be, think about it this way: it just reflects the idea of space-time having negative, or concave, curvature. The opposite of this theory is that the universe has positive, or convex, curvature—that it’s like a sphere.

What exactly does this idea of curved space mean? It means that if you made a slice through space at a fixed moment in time and tried to draw a triangle on a really huge scale (millions of light-years across), it wouldn’t be a proper, two-dimensional triangle. It would either be weirdly bloated (if the universe has positive curvature), or weirdly sunk in (if the universe has negative curvature). That’s what you can see in the first two shapes in the image at the top of this page.

The third option is that space-time isn’t curved—it’s flat. Triangles are really triangles, however big you draw them. The universe-as-video-game scenario depicts a flat universe. But the idea that our universe is flat and loops around like a Pac-Man game got ruled out a long time ago, Mersini-Houghton tells me. That universe just wouldn’t have enough dimensions. (To be fair, Greene says the same thing, ten pages later. But that was ten pages of me picturing us all as Pac-Man characters!) And there’s another possible flat-universe scenario: that space-time just goes on, flatly, forever: a tabletop with no edges, as Greene describes it.

So are triangles really triangles—is the universe flat, or curved? Scientists have suspected for a while now that it’s flat, Mersini-Houghton says. “There was about a 95 percent chance that the universe is flat, and a 5 percent chance that it’s like a hyperbola,” she says. (At this point, none of the evidence favors the spherical-universe idea.) Then a NASA spacecraft, WMAP, measured an angle formed by two “sides” comprised of the distance microwave background radiation has traveled since the Big Bang—and confirmed that the resulting triangle is flat, or darn close to it. Scientists are watching to see if the Planck satellite, which can take even more accurate measurements than WMAP’s, confirms the flatness. “We’ll know for sure in a year, when the data from Planck are published,” Mersini-Houghton says.

It looks like we’ve got a flat universe on our hands. Flat, and infinite. There’s just one problem, according to Mersini-Houghton: our understanding of the Big Bang suggests that the universe isn’t infinite. “We know how big the universe is,” she says. “In meters, it’s a ten with twenty-five zeros after it. That’s really big, but not so big that we can’t imagine it.” That’s the distance that light from the edges of the universe has traveled in the fourteen billion years since the Big Bang. How could anything possibly exist outside that range?

Easily, Mersini-Houghton says, if it were created by a different Big Bang. That is, if it were part of a different universe.

The idea that there might be many universes isn’t anything new: physicists have being finding hints of it in their equations since the 1950s. But many of them ignored the possibility of a multiverse because, well, it seemed kind of crazy.

But in 2006, Mersini-Houghton and colleagues started making testable predictions of what neighboring universes might be doing to our own. They said another universe is pulling some of our matter toward it, creating a void in space. They predicted where this void would be; eight months later, scientists found it. Since then, there have been more findings that suggest that the multiverse might be for real. The most compelling was a 2008 finding that huge numbers of galaxies are moving the wrong way, independently of the path laid out for them by the expansion of space that’s been happening ever since the Big Bang.

It can’t be something like a black hole doing it, because that would affect only the galaxies in the neighborhood of the black hole,” Mersini-Houghton says. Whatever’s making these galaxies move is influencing a huge amount of mass. Supporters of the multiverse idea think this means the galaxies are being drawn to something outside our universe.

So our theory becomes a flat, infinite multiverse, with finite universes scattered across it like cookies on an endless cookie sheet. (That’s my simile, so we’re using my preferred snack food.) I like this theory, and not just because I prefer sweets to salty Pringles. But if you’re not satisfied yet, or you want to learn more about the history of the cosmos, Mersini-Houghton and other scientists are going to be on the Science Channel on Wednesday, June 15, answering the question, “Is there an edge to the universe?”

Also, Greene’s most recent book is about the possibility of a multiverse or parallel universes. I haven’t read it yet, but I hear Greene has moved on from The Simpsons to South Park. (Fans of Kenny should be pleased: it’s Cartman whose life is risked to explain potential and kinetic energy.)

Laura Mersini-Houghton is an associate professor in the Department of Physics and Astronomy in the College of Arts and Sciences.

—Susan Hardy

A week of standing up

It’s not as hard as it sounds.

I like to think of myself as an active person. I run, I walk, I lift weights.

But the truth is, I spend only a small fraction of my waking hours doing things that I could call “exercise.” A lot of the time, both at work and at home, I’m just plain sitting—whether it’s in front of my computer, in a meeting, or on the couch. And more and more research now seems to be showing that all this sitting is hurting me.