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Archive for August, 2009

The opportunity cost of exercise

August 31st, 2009

Exercise is good for us — that’s one of the main themes of this blog, and one that I’m sure not many readers would dispute. But it can take a lot of time. Someone training for a marathon might easily spend more than 10 hours a week running, stretching, showering and so on. What is the opportunity cost of spending all that time? Justin Wolfers, an economist at UPenn’s Wharton School, did a somewhat tongue-in-cheek segment for NPR’s Marketplace analyzing the economics of running:

Runners World magazine recently argued that marathon running is an incredibly cheap sport. All you need is a pair of shoes, and you’re off and running. But they’re wrong.

You see, they were emphasizing the out-of-pocket cost, which is small. But the foundation of all economics is something called opportunity cost. It says that the true cost of something is the alternative you have to give up.

It’s an amusing piece, as well as a primer on some basic principles of economics like opportunity cost and the law of comparative advantage. But he makes a few asides that get the commenters riled up (see also Wolfers’ entry on the Freakonomics blog). And his analysis is (necessarily, I guess, given the space requirements) pretty simplistic. I think he could make a much stronger case for the mental and physical benefits of running that would yield real financial rewards. Fortunately, he still comes to the right conclusion: running is worth it!

World Champs marathon

August 22nd, 2009

Just finished watching the marathon from the IAAF World Championships in Berlin. Watched the leaders running live through Internet streaming, and followed the Canadians in real time as they posted 5K splits on the IAAF website. It’s a race I was particularly interested in because of an article I wrote last year about Canada’s marathon standards (which earned a National Magazine Award). In 2008, Canada sent no marathoners to the Olympics; this year, in contrast, they sent four men and one woman. So how would this team fare, with its easier standards?

It was a mixed bag, but there were some very encouraging results. Take Reid Coolsaet — some excerpts from his blog:

I’ve been geeking out looking over results and time splits from the past few World Championships to see different pacing strategies.  Seems like a lot of guys go out too hard and fall off pace, often not finishing and saving it for another day.  For a top 10 finish you almost always have to go out with the lead group but there are numerous examples of top 20 and 30 finishes with more sensible pacing strategies. [...]

Don’t expect to see me in much TV coverage as the cameras will be concentrating on the leaders.  I’m ranked about 95th out of 100.  Expect me to improve on that ranking.

Unfortunately, the results on the IAAF website are messed up right now, so I can’t give as full a breakdown as I’d like. But here are a few details on Reid’s performance:

[split] / [place]

5K / 75

10K /64

15K / 69

20K / 54

25K / 40

30K / 36

35K / 28

42.2K / 26

Fantastic (and very smart) race for a guy who was ranked 95th. Congratulations, Reid! (And also to Dylan Wykes, who executed the exact same game plan until the last few kilometres, where he lost just a few places but still finished in the top half of the field.)

That’s all for me for a week. Tomorrow morning, I fly to Alice Springs for some hiking in the Australian outback. Should be lots of fun, and I’ll be back on August 30.

Will exercise make me gain weight?

August 19th, 2009

Just when I thought I’d vanquished this beast (see the most recent Jockology column, “Statistics Canada says being overweight makes you live longer. Should I stop exercising?“), TIME magazine comes out with a cover story called “Why Exercise Won’t Make You Thin” that has been making waves. The author, John Cloud, sifts (somewhat selectively) through several decades of research, and reaches the following conclusion:

In short, it’s what you eat, not how hard you try to work it off, that matters more in losing weight. You should exercise to improve your health, but be warned: fiery spurts of vigorous exercise could lead to weight gain. I love how exercise makes me feel, but tomorrow I might skip the VersaClimber — and skip the blueberry bar that is my usual postexercise reward

The piece has already spawned numerous rebuttals (see this one from Obesity Panacea), along with complaints of misinterpretation from one of the scientists cited. My thoughts? The research he discusses isn’t actually that controversial. For instance, the idea that exercise will actually make you consume more calories than you burn off has been debated for years. (Here‘s a Jockology column I wrote on whether post-exercise eating negates the benefits of exercise.) There are lots of questions that scientists still haven’t nailed down about how diet and activity levels interact to influence health.

What’s way out of whack with Cloud’s article is the conclusion he draws. Somehow the fact that regular exercise doesn’t automatically cause people to lose large amounts of weight gets twisted into an attention-grabbing warning that exercise might actually cause you to gain weight. Where’s the evidence supporting this bold claim? Nowhere. Basically, it reads like the kind of story that has a “bold, counterintuitive” claim that was agreed on at an editorial meeting long before anyone actually did any research.

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Doping at the old folks’ home

August 19th, 2009

There’s a fun article by John Leland in the New York Times looking at drug use among masters track and field athletes:

In his apartment outside Philadelphia, Frank Levine pulled a list of prescription medications from his refrigerator, his hands shaking slightly. There was metformin HCl and glipizide for his diabetes; lisinopril for his blood pressure; and Viagra.

“I need it,” he said recently.

Mr. Levine, who is 95 and has had operations on both knees, in June set the American record in the 400-meter dash for men ages 95 to 99…

Leland interviews a few athletes who suspect that some people are dipping into banned drugs in order to win prizes in advanced age groups. It’s hard to imagine an 80-year-old shot-putter injecting himself with steroids, but I guess we should never underestimate the power of human vanity. The grey area, as the article points out, is that there are plenty of performance enhancing drugs that also have real therapeutic benefits — and the older you get, the greater the chance that you’re legitimately being prescribed one of these drugs.

Fatty foods hurt memory and exercise

August 16th, 2009

It may be true that carrying a few extra pounds isn’t the end of the world. But that doesn’t mean fat is innocuous: Tara Parker-Pope has an article about some very interesting experiments in rats that show a clear and rapid effect of eating fatty foods.

[T]he new research shows how indulging in fatty foods over the course of a few days can affect the brain and body long before the extra pounds show up…

“We expected to see changes, but maybe not so dramatic and not in such a short space of time,’’ said Andrew Murray, the study’s lead author and a lecturer in physiology at Cambridge University in Britain. “It was really striking how quickly these effects happened.’’

The same group has done similar experiments on people, though the results have yet to be published. It’s an interesting article, definitely worth a read.

Jockology: get fat, live longer?

August 13th, 2009

A couple of weeks ago, the Globe’s Margaret Wente published an article called “Get fat, live longer,” spurred by a recent Statscan study suggesting that overweight people live longer than normal-weight people. It launched a bit of an Internet firestorm as people forwarded the article around with glee. The article itself was reasonably good, with the exception of one major clunker: she said that “obese” people (BMI 30-35) lived longer, whereas in fact it was just “overweight” people (BMI 25-30) who demonstrated the effect. Still, the message many people took from the article — “get fat, live longer,” — wasn’t quite what the research suggested. So I decided to address a couple of points in this week’s Jockology column:

The question

Statistics Canada says being overweight makes you live longer. Should I stop exercising?

The answer

Let’s start with the facts. In June, Statistics Canada researchers did indeed publish a study in the journal Obesity based on a 12-year analysis of 11,326 Canadian adults in the National Population Health Survey. They found that subjects who were overweight (body mass index of 25 to 30) were 17 per cent less likely to die during the study period than those of normal weight (BMI of 18.5 to 25).

Now on to the interpretation.

These results fit right in with a growing amount of evidence that body weight is not the absolute indicator of health we once thought.

But that doesn’t mean exercise isn’t important. In fact, it turns out that physical fitness is a far better barometer of your long-term health than weight is – and that holds true even for thin but inactive people who thought their fabulous metabolism meant they didn’t need to exercise at all. [read the rest of the column...]

For another very detailed take on this research, check out this post by obesity researcher Travis Saunders on the blog ObesityPanacea.

Watching TV makes you slack during your workout

August 13th, 2009

Good article in the Toronto Star by Paola Loriggio about the trend towards high-tech gyms. For example: the Gold’s Gym in London, Ont. that just opened one of the country’s first “cardio gyms,” where users can watch cinema-sized screens in a dark room while sweating on their cardio machines. She lists some pros and cons; most interesting to me is the following:

There’s a reason workouts seem easier when you’re watching TV – it’s because they are.

Researchers at Elon University in North Carolina studied the effects of various distractions on exercisers, and found those watching television didn’t work as hard as those listening to music, or toiling in silence.

“They were working at a very, very low intensity,” says Paul Miller, one of the researchers involved in the study, performed in 2005-2006 and slated for publication later this year.

“I think they got so engrossed, they didn’t pay attention to physical cues.”

Music, in contrast, apparently helps people push harder. I’ve often wondered about this. I suppose if you were running on a treadmill, and knew in advance what pace you wanted to run, you could just set the treadmill at that pace and it wouldn’t let you slack. Still, it’s food for thought.

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Beet juice boosts endurance

August 11th, 2009

Today’s “exercise in a bottle” study: beet juice can help you exercise for up to 16 percent longer, according to researchers at the University of Exeter.

After drinking beetroot juice the group was able to cycle for an average of 11.25 minutes, which is 92 seconds longer than when they were given the placebo…

The researchers are not yet sure of the exact mechanism that causes the nitrate in the beetroot juice to boost stamina. However, they suspect it could be a result of the nitrate turning into nitric oxide in the body, reducing the oxygen cost of exercise.

For the record, the study consisted of eight men, who took 500 mL of beet juice for six straight days. The presence of nitrate isn’t something I’d ever heard of before, so maybe there’s some new science here. Certainly, the researchers seem to be pretty excited about it.

“We were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training. I am sure professional and amateur athletes will be interested in the results of this research,” [said Professor Andy Jones].

My personal prediction: don’t look for Tour de France riders or Olympic runners to be downing beet juice anytime soon. I’d stick with training.

CRMag: massage and lactic acid, Achilles debridement, reading on the treadmill and more

August 11th, 2009

The September-October issue of Canadian Running magazine is back from the printers, and should be in the mail and on newsstands soon. As usual, lots of good stuff — a profile of Ray Zahab, a pilgrimage through the three big-city U.S. fall marathons, and a Q&A with the ever-entertaining Reid Coolsaet, who’s currently in Berlin to run the marathon at the World Championships. Also, our editorial director, Dave Chaundy-Smart, tried out the Internet coaching offered by legendary Olympic marathoner Jon Brown. And finally, my regular Science of Running column covers the relationship between vitamins and exercise, a new gadget for reading on a treadmill, a new approach to Achilles tendinitis, the physiology of massage, and good news about marathons and heart damage.

Barefoot running: theory versus practice

August 10th, 2009

With the publication of Chris McDougall’s Born to Run this spring, there’s been a flurry of interest in barefoot running (or minimalist running, which involves donning ultralight shoes like the Vibram FiveFingers, whose function is to keep your soles clear of broken glass and doggie doo rather than support your ankles). I had an interesting chat with McDougall for an feature I wrote in the July-August issue of Canadian Running (an excerpt is available here, but the full article isn’t available online at this point). I mention this because a reader just forwarded me a good overview of the topic from Wired, which offers its usual research-backed take on the topic [thanks for the tip, Adam].

To me, the jury is still out on this one. I like the theory behind minimalist running, and am willing to believe that, for those who take the time to build up slowly and do it right, it may be a route to injury-free running. But in practice, I’m not convinced that it’s widely applicable in our concrete-covered world, especially for people who have grown up wearing shoes. The extreme patience and diligence needed for a successful transition to barefoot running are precisely the qualities that most of us fail to demonstrate when running in regular shoes — which is why we get injured in the first place. So I think minimalism will remain a minority option for a small group of very methodical people who have tried and failed to run injury-free in regular shoes, but are truly committed to finding a way to run.

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