Friday, November 21, 2008

What exactly is "moderate" exercise?

That's the question posed by a study in progress being done at the State University of New York and Syracuse University.

The Surgeon General recommends that everyone get 30 minutes a day of moderate exercise--but what, exactly, does that mean? Language is powerful but not always specific; what feels moderate to you might feel excessive to me, or maybe underwhelming.

Researcher Cameron Hall set out to explore people's perceptions of moderate exercise. I was lucky enough to be able to volunteer for the study, and it's been fun. On the first visit, I came into the lab, where they hooked me up to all kinds of monitors and meters and put me on a treadmill to measure my maximum exercise tolerance. They measured my oxygen consumption, heart rate, and perceived levels of exertion with one of those little charts where they ask you to point to how hard you think you're working. Pretty damn hard, by the end.

On the next visit, I was asked to walk around a track at what I thought was a moderate level of exercise. I booked it, let me tell you, wanting to surpass the researchers' expectations of me. I walked much faster than usual, averaging around 4 miles per hour instead of my usual 3.7. On the third visit, we were back in the lab, only now the researchers were telling me how fast and hard I had to work to hit the middle part of my range by the numbers.

It turned out that what I think of as moderate is nowhere near what the numbers say. Visit 3 was excruciating because we had to keep the treadmill flat for comparison purposes to the track we used on visit #2. I had to walk 4.2 miles an hour and even then could barely get into my moderate heart and oxygen consumption ranges. This might not have been a problem if I were, say, six feet tall. But I'm just about five one, and my legs just aren't that long.

So I learned what I personally have to do to get in the recommended half hour of "moderate exercise": Set that treadmill at 3.8 and crank up the incline to between 3 and 5 percent. I did it yesterday, and let me tell you, I was working hard. And that's what the researchers think will be the upshot of the study: You probably can't protect your cardiovascular health by strolling around the block with the dog or taking a leisurely stroll. You've gotta book it, baby.

What I love about this study is that it acknowledges both the power and pitfalls of language. Words are imperfect vehicles for expressing what we feel and what we know. But they're all we've got. Sometimes our task is to learn to use them more expressively. Sometimes, as in this case, our task is to connect them to cold hard facts.

The study results should be published within the next few months. I'll keep you posted.


Anonymous said...

How the government or sports medicine vested interests define moderate is meaningless and does not determine an activity's healthfulness or its value for helping people of all ages maintain health and function. Reaching some number doesn't = better. The importance being placed on exercise as such goes far beyond what has been shown in aging and geriatrics research. Sounds like one more thing they're trying to get us all to obsess about -- next they'll have us all wearing oxygen meters and our numbers automatically reported to the Surgeon General.

Anonymous said...

I take a tiny little issue with this statement:
"You probably can't protect your cardiovascular health by strolling around the block with the dog or taking a leisurely stroll. You've gotta book it, baby"

I think the message we would want to convey is, figure out where you are, know where you aim to be, and work up to that. A "book it, baby" message might make it seem like a stroll around the block or walking the dog are useless -- which they aren't. I think we need a "build on where you are" message, even if people are exercising at less than optimal levels for cardiorespiratory fitness.

I've been struggling with some GI problems that make it hard for me to exercise at the intensity I find the most rewarding -- and I feel guilty and like I'm losing important fitness ground every minute -- which doesn't do much good for my emotional health or stress levels.

It is great that you figured out what you, personally, might want to do to best protect your heart health. But when it comes to translating it to the general public, I would love it if the message wasn't "you aren't doing enough" and instead was "here's how to get the most out of your activity to protect your heart."

Anonymous said...

Also, have you seen this article?

I would really value your take on it.

kcd said...

The message I got from this very thorough, informative post was, Just give the f*ck up, dude, you can't even get CLOSE to moderate.

I must say that I think that it's tremendously misguided to characterize anyone's moderate exercise as anyone else's. I'm heavier and more sedentary than I've ever been, and I hate it. It is so hard to move, let alone enjoy movement. And believe me, a stroll with the dog WOULD be moderate exercise.

I don't know, dear blogger, if my impression is correct, but there was something in your initial post that looked to me to get your competitive fires burning. I don't believe in competition - I find it, for me (only) completely inimical to acceptance, to health at every size, and, most importantly, to joy (i.e. the joy of movement).

Just wanted my impression to be counted. I will keep strolling with (or without)the dog because that's all I can do, other than water running, water aerobics, and water walking, and I could give a fig what an agency says about it. I guess I was surprised to find a post in the fatosphere that made me feel most definitely non-HAES, like wherever I am, it's not good enough.

Food for thought only - no invective here. Thanks for listening,


Harriet said...

OK, time for a little clarification. :-)

I completely agree that any exercise is better than nothing. And I apologize if my original post smacked of competitiveness or intimidation. That was not my intention at all. BY all means stroll with the dog, climb another set of stairs, frolic in the leaves. I do, and it "counts" because among other things it makes me feel better mentally and physically.

I was quite surprised by these findings, and in my enthusiasm for communicating them obviously left the wrong impression.

The point is that the "moderate exercise" recommendation is more fodder for all those folks who criticize those of us with a BMI over 25 for being lazy, and for those who think it's easy to be thin and anyone who isn't is another headless fattie.

I would venture to say a hell of a lot of people, fat and thin, don't meet the "moderate exercise" criteria as defined by physiological measures like O2 consumption and heart rate, because you've got to practically take your own legs off to do it. I do, anyway. So a big red F goes to the government in the first place for applying such a mushy descriptor, and for implying that what they're talking about is easy/gentle/accessible to all.

(Can you tell I'm in grading mode??)

Anonymous said...

Thank you for the clarification.
Grading mode would certainly have an impact on one's perspective :-)

I think that if I performed similar tests on land vs. in the pool, I might find that I can much more easily get into the "right zone" in the pool than I can on land, because of how much I enjoy it, and that I'm using my whole body, not just my legs, and that my weight is supported by the water. So I don't know if using only treadmill/track would truly be measuring what I do.

I have used a heart rate monitor in the past and found it was really hard to get into the zone I was aiming for and staying there, but when I'm swimming laps and I take a break, I realize my heart is really pumping. If I were to use a heart rate monitor again, I think I would do better now than I used to, in the pool, at least. (Of course, it helps that as I'm older, I don't have to get my heart rate up as high -- the last time I used one I was still in my 20s.)

Another thing to consider is that maybe staying at that level of intensity isn't necessary, that working between a perceived exertion of 5 and 7 with forays into the 8-9 range might be good, too.

I know that when I'm walking briskly, I'm not working anywhere near as hard as I am when I'm walking/jogging on the treadmill or swimming laps.

Intersting to think about. Also interesting to think about what supports people might need and want to be able to get to that moderate level. I know that if I am working at a perceived exertion of 6 or 7, I am probably going to want to change clothes afterwards, which makes it a little hard to do during working hours (not impossible, but hard).

Harriet said...

Interesting--you must be using a different perceived exertion scale than these guys. Theirs went from 1 to 20. During the max test I hit 18, and during the other 2 days I hovered around 13-14, which is apparently where I need to be. Yours must be 1-10? That's probably equivalent.

To stay in the zone, or close to it, I had to be moving every part of my body--swinging the arms hard, working the chest, etc. So yeah, something like swimming would no doubt be much better. If only I could swim. :-)

Anonymous said...

I guess I question how they know that "walking the dog" speed doesn't help your heart, vs. "OMG I'm going to die" speed. As a 5'2" fat person with short legs, 4 mph requires kind of a half-jog thing - I literally cannot walk that fast with any degree of comfort. Jogging is not, to my perspective, moderate exercise at all. Also, what is heavier than moderate exercise? Is it only things you can physically do for a minute at a time?

I must be reading this in a really awful frame of mind, but this is fucking depressing, and just adds to the "never good enough" thing, especially considering people are now supposed to be exercising about 1.5 hours a day for "heart health." Is there any hope for those of us that legitimately hate exercise, and don't want to spend every fucking minute running on a treadmill? (Not your fault, and I'm sure there's legitimate social/political critique to be made, but I'm so sick of discovering that no matter what, I'm always going to be unfit, fat, and lazy.)

Anonymous said...

I'm wondering how much the scale used by the researchers was subjective. One thing I've discovered since I got my heart rate monitor watch is that I can get into the "aerobic zone" for my age by walking at about 2.5 MPH, IF I've used my inhaler. If I haven't used my inhaler, I FEEL like I'm above the aerobic zone around 2.1 or 2.2 MPH - I'm breathing really hard - but I'm actually below it.

I do understand they're probably measuring oxygen usage as well as heart rate (and other things?) but heart rate is easiest for us laymen to check :)

Anonymous said...

Perhaps I'm in the minority, but I'm not sure I understand what's so surprising about this. I run an hour at about 5.5 mph several times a week, and it feels ploddingly slow. Most people I see at the gym run significantly faster than that. If I went any slower, I'd feel like I weren't doing anything. Walking doesn't even feel like exercise at all.

Harriet said...

We each have a different threshhold for exercise, as we do for so many things. What feels ploddingly slow to you might feel quite intense for someone else, anon. That's why the study did not compare people with one another but measured individual setpoints of oxygen consumption, heart rate. etc.

Anonymous said...

I think this is quite useful, I look forward to reading the study when it comes out. I exercise at a leisurely rate when I walk or bike, which is why I go to the gym and do step/kickboxing. I just won't work that hard on my own.

And I don't know about other people's dogs, but my dog sniffs EVERYTHING, and pees every 4 minutes, so it's quite slow. Not even close to exercise, for me. If I'm actually going to count walking for exercise, it's got to be a few hours with substantial elevation change.

Anonymous said...

That's interesting. I'm sure my idea of moderate exercise is incorrect.

One thing, though, that's been bugging me: long legs do not help you go faster. Saying that would be like saying that making wheels on cars a lot bigger would make cars go a lot faster. Long legs let you take longer strides, but speed is about exertion, not length.

I know that's really not important to the topic at all, but I noticed people alluding to that idea and, as an extremely tall person, that assumption bothers me a bit.