One afternoon not long ago, a friend and I were talking at her dining-room table, and I'll admit it, we were feeling a bit self-righteous.
We'd gone bowling with her parents, and we both noticed her mom could barely roll the lightest ball down the alley. She struggled with a lot of other tasks, too. We didn't think of her as an elderly person. But there she was, looking feeble.
"Well," my friend said, shaking her head, "she doesn't really exercise." I nodded knowingly.
The way my friend and I see it, there are two kinds of people: exercisers and everyone else. We - the exercisers - prefer to sweat, not sit. They - we'll call them "the relaxers" - prefer to read, not run. They think we're nuts. We think they're slowly letting themselves wither.
We'll call this The Great Divide, and my friend and I patted ourselves on the back for being on the right side of it. Then we got up to leave.
"Ouch," I winced, grabbing at my hamstrings.
"I'm sooooo sore!" she groaned.
And as we hobbled away, we felt decidedly less smug.
Are you laughing at us? Nodding sympathetically? Either way, we'll hazard a guess: Whichever side of The Great Divide you're on, you can't imagine living the other way.
"People internalize an image of themselves as an exerciser or not," says David B. Coppel, a sports psychologist at the University of Washington.
So before we go any further, I'll confess. I used to think people such as me - who exercise four, five, six times per week - were crazy. Three years ago, I described my physical condition as being "what you might expect for someone who types for a living."
Another confession: Despite the incident at the dining-room table, this article is not going to say exercise is bad for you. Sorry, relaxers.
Because we can hear the complaints already, we will admit that at times, if you go overboard, it can definitely beat you up. OK, it can beat you up even if you don't go overboard.
But we're going to explain that, too. So stick with us as we take a run at some of the biggest hurdles to becoming an exerciser.
I'm perfectly fine the way I am, thank you. I'm not even overweight.
The truth is, getting up and moving is good even if you're thin.
It turns out being sedentary is a health risk. Period. It's up there with high cholesterol, high blood pressure, even smoking, according to a 2010 article in the Journal of the American Heart Association. In fact, fitness level is a "more powerful predictor" of survival than traditional risk factors, the journal says. That means an active person who's overweight can have a better prognosis than a thin, sedentary person.
•Can reduce your risk of getting, or dying from, certain cancers;
•Can delay or avert Type II diabetes, as well as reduce your mortality risk if you have diabetes;
•Can help maintain your cognitive function into old age.
Is that enough? OK, one more thing:
Studies - including one by the American Cancer Society - have shown sitting itself can take years off your life. It's not just that you're burning fewer calories. It's that certain bodily processes go silent - processes that do things like regulate your insulin and get the fat out of your bloodstream.
"Excessive sitting," a Mayo Clinic researcher was quoted in The New York Times as saying, "is a lethal activity."
But I do exercise … sometimes. That's what a lot of people tell themselves.
In surveys, a consistent 30 to 35 percent of people report moderate to vigorous levels of physical activity. But in the past few years, researchers have begun to outfit study participants with devices that record movement, and the truth has come out: Fewer than 5 percent of adults are doing the recommended level of activity.
Do I really need this? I'm young and healthy.
Yes, says Kevin Conley, a University of Washington radiology professor who has developed contraptions to measure muscle activity as well as something in the muscles called mitochondria. These are the powerhouses, where the body turns fuel into activity.
Conley compared three groups: active adults, inactive adults and the elderly, and looked at fitness in a variety of ways. As expected, the seniors had fewer mitochondria. But so did the inactive adults. In fact, in each area measured, the inactive adults had scores that were close to - or worse than - the old folks.
"Inactivity does the same thing as aging," Conley says. "It was so astonishing at first I didn't believe it myself."
Why should you care? Because it becomes a vicious cycle. Don't exercise and your mitochondria decline, which makes you less able to move, which leads to fewer mitochondria and so on.
The moral of the story is, you can choose to get old before your time.
But I'm so out of shape.
This is a pet peeve of another local academic, Glen Duncan, associate professor of epidemiology and nutritional sciences at the UW.
"I get very frustrated when people say things like, 'I can't walk up the steps,'" he says. "The reason you can't walk up the steps is because you're deconditioned, and the reason you're deconditioned is because you never walked up the steps."
He pauses. "You did it to yourself."
Didn't you hear me? I said I can't walk up the steps.
OK, don't walk up the steps (yet). Try strength training.
Every local expert we talked to, as well as a number of national groups, say strength training, like weight lifting, can be more important than aerobic activity, especially as we age.
If you don't maintain your strength, things start to slide. It might be the stairs that give you trouble first. Then it's flat ground. Then it's getting out of a chair. Seriously. It happens.
I'm afraid I'm going to hurt myself.
You're right: When you exercise, you're putting strain on your muscles, your bones, the whole shebang. But that very stress is what tells the body to build.
Scientifically speaking, says Michael Regnier, a bioengineering professor at the University of Washington, "When you exercise, it stimulates the release of hormones that signal the cells to start protein synthesis."
When you lift a heavy load, it puts compressive forces on your bones. Those compressive forces tell the bones - uh-oh, we'd better get stronger. It increases their density. Cartilage, as well, gets its nutrients from moving. So you are stressing your body; you're also building it up.
But I'm afraid I'm really going to hurt myself.
Perfectly reasonable. How many times have you read the warning, "Consult your doctor before beginning any exercise program"?
It used to be that health authorities thought it could put people at risk of a sudden heart attack. The advice has always been, take it easy!
Regnier thinks people have followed that advice a little too well. "They've over-minimized," he says.
Health authorities now believe it's riskier not to exercise. "Sudden death," a major federal report says, "is, more accurately, a risk of inactivity."
But I'm too old! Why bother at this point?
Admittedly, when we age, our bodies tend to fall apart on us.
But professor Conley found something interesting with his mitochondria-measuring contraption.
Scientists used to think the decline of those powerhouses was inevitable, and it started as early as the 40s and 50s.
The bad news is, it is inevitable. The good news is, the inevitable part doesn't start in middle age. We can stave it off until we're in our 70s or 80s - if we take the time to exercise.