Archive for December, 2009

Cardio makes you smarter (and more educated and successful)

December 31st, 2009

To ring in the New Year, some good news for those who have been exercising (and for those who haven’t, some incentive to get started in 2010!). It’s yet another study linking cardiovascular fitness and intelligence — a familiar topic, but with a few interesting wrinkles.

Swedish researchers examined the records of 1.2 million men who enlisted in military service at the age of 18 between 1950 and 1976, including 268,000 pairs of brothers and 1,432 pairs of identical twins (read the abstract from the Proceedings of the National Academy of Sciences here). The researchers were particularly interested in young adults, because it’s a time when your brain changes rapidly. Intelligence was positively correlated with cardiovascular fitness (as measured by stationary biking), but there was no correlation between intelligence and muscular strength.

In addition, cardiovascular fitness at age 18 often predicted socioeconomic status and educational attainment later in life. When the researchers examined the twin data, they found that environment, not genetics, played the biggest role in these associations.

To be more precise, genetics explained less than 15% of the variation, while environmental influences explained more than 80%. So fitness is, to a large degree, within your control.


Jockology: Don’t think, just do it

December 24th, 2009
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This week’s Jockology column is about performing under pressure — though it has surprising applications even to simple tasks like running:

The question

When the game is on the line, should I take my time with the ball or just get it over with?

The answer

When you’re lining up a crucial putt, the last thing you want to hear is an impatient jerk behind you yelling, “Hey buddy, could you hurry it up a bit?”

But new research suggests that jerk may be doing you a favour.

Psychologists and neuroscientists are finding that when we perform complex motor sequences that we’re very familiar with, concentrating too much on the details makes our performance worse. It’s what causes choking on the putting green or at the free-throw line – and it’s why a bit of a distraction can be a good thing. [read on…]

Does Canada’s “Top Secret” research undermine the Olympic spirit?

December 24th, 2009
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Of the $117 million spent by Canada’s “Own the Podium” initiative over the past five years, $7.5 million has been allocated to a research program called “Top Secret.” This program aims to produce exclusive technologies that will help Canadian athletes win medals at the 2010. For the most part, it’s the kind of thing you’d guess — advanced speed suits, better bobsleighs, fasters skate runners, and so on.

The question is: Is this fair? In the past, Canadian athletes have often been on the losing end because teams from the U.S. or Europe or Australia had more sophisticated equipment; now we’re trying to turn the tables. But sports technology has been in the spotlight recently, thanks to issues like the fancy new swimsuits that have seen 250 world records topple in the past two years — and which will be banned starting in 2010.

For an article in the Jan.-Feb. issue of The Walrus magazine, I visited some of Canada’s leading sports technology researchers at the University of Calgary, and headed to the Australian Institute of Sport in Canberra, which is considered a model for advanced sports science. I also spoke the ethicists, and the inventor of the Therma-Blade heated hockey skate. And I ended up with some distinct opinions about whether we should continue funding programs like Top Secret… You can read the article, “Faster, Higher, Sneakier,” here.

How to run up and down hills

December 23rd, 2009

You lose more time running up a hill than you gain by running back down the same hill — that’s a basic observation that runners quickly learn from experience, in the same way that a tailwind never helps you as much as a headwind hurts you. Studying this in the lab, though, is challenging, because treadmills don’t let you vary your pace naturally. That’s why I was interested to see a neat little study on hill running in the January issue of Medicine & Science in Sports & Exercise from some Australian researchers at Queensland University of Technology.

What’s neat is that they performed a “field study” of runners on a roughly 10-kilometre time trial, divided into three laps, with one big uphill and one big downhill on each loop. To collect data, the runners wore a portable gas analyzer that measured oxygen consumption, a GPS receiver to measure speed and acceleration, an “activity monitor” that measured stride rate and stride length, and a heart-rate monitor.

As you might imagine, the researchers used all this gear to collect a huge pile of data, and their paper contains quite a lengthy analysis of the various factors affecting running speed. It turns out that the study participants ran 23% slower on uphills, but only 13.8% faster on downhills — so we do lose out on hilly course. Stride rate stays nearly constant while going up and down hills, while stride length varies. And so on.

There are also some practical lessons to be learned. Read more…

Exercise vs. calorie restriction: head-to-head match-up

December 18th, 2009

Fitness or fatness: which is more important in determining your health? As I discussed in this Jockology article, some researchers (most notably Steven Blair at the University of South Carolina) believe that most of the health problems we associate with obesity are actually a consequence of poor aerobic fitness. In other words, they argue, it’s okay to be a little portly as long as you’ve exercised enough to have good endurance.

This challenges the basic tenet of old-school, keep-it-simple nutritional thought — that good health is simply a matter of matching the calories you eat to the calories you burn. Can your body tell the difference between a calorie burned through exercise and a calorie avoided through dieting? Well, a really interesting and excruciatingly careful study from researchers at Louisiana State University has just tackled this question.

calorie-restrictionHere’s the gist: 36 moderately overweight subjects, divided into three groups. One group was the control, and stayed exactly the same during the six-month study. A second group cut their calorie intake by 25 percent, while the third group cut calories by 12.5 percent and increased calories burned through physical activity by 12.5 percent.

As expected, the two intervention group lost exactly the same amount of weight (about 10 percent of their total), and they both shed roughly the same amounts of total fat and visceral fat. This makes sense, because they were both operating under identical calories deficits. Here’s the rub, though: only the exercise group had significant improvements in insulin sensitivity, LDL cholesterol and diastolic blood pressure.

This tells us that a calorie is not just a calorie — it matters how you cut calories. And, as Steven Blair is constantly pointing out, being thin is no guarantee of health if you’re not active. (And, as a nice bonus, it also tells us that it’s possible to drop 10 percent of body mass through a combination of diet and exercise — though it probably helps to have a team of researchers cooking your meals and supervising your exercise!)

The American Dietetic Association’s new position on nutrient supplementation

December 15th, 2009

I’ve written a bunch about supplements recently, but bear with me for one more quick post. The American Dietetic Association just released its new position stand on “nutrient supplementation.” (The full text is available here.) A few interesting nuggets in there — for one, they note that supplement sales in the U.S. totalled an astounding $23.7 billion in 2007. About half of Americans take dietary supplements, and in particular about a third take a multivitamin/mineral (MVM). However you slice it, that’s a lot of money.

The basic gist of the position stand is as follows:

It is the position of the American Dietetic Association that the best nutrition-based strategy for promoting optimal health and reducing the risk of
chronic disease is to wisely choose a wide variety of nutrient-rich foods. Additional nutrients from supplements can help some people meet their nutrition needs as specified by science-based nutrition standards such as the Dietary Reference Intakes.

Pretty basic stuff. As you read further, it gets a little more forceful:

Although MVM supplementation can be effective in helping meet recommended levels of some nutrients, evidence has not proven them to be effective
in preventing chronic disease
. A study published in 2009 from the Women’s Health Initiative found no association between MVM supplementation and cancer or cardiovascular disease risk or total mortality in postmenopausal women…

They then do a pretty good job of summing up the evidence for and against various health claims, like vitamin B-12 and cognitive function, vitamin D and bone health and so on. If you’re taking vitamins, it’s worth a look to see what they have to say about the benefits you’re looking for (though it’s a far from comprehensive list).

The bottom line for me (as I ranted in a recent comment) is that supplements offer many people a false sense of security with, in many cases, very little evidence to back them up. Eating enough fruits and vegetables is a real challenge — one that I certainly struggle with, especially at this time of year — but I’m not sure it’s helpful to convince ourselves that coming up short doesn’t matter because we’re taking some pills that will compensate.


Jockology: vitamin C may slow muscle recovery and inhibit fitness gains

December 10th, 2009

This week’s Jockology column delves into the highly controversial body of research on antioxidants and exercise:

The question

How do antioxidants affect my workout?

The answer

Sales of orange juice are soaring as people seek flu protection from vitamin C, The Globe and Mail reported last month.

Old habits die hard, and our faith in the power of antioxidants is deeply entrenched. Over the past few years, a vast series of studies involving hundreds of thousands of subjects have failed to find any health benefits from antioxidant supplements.

Now, a handful of studies suggest that popping these pills may even block some of the benefits of exercise, and even slow down post-workout muscle recovery. [read on…]

Not to spoil the ending, but to me this research is yet another reason to focus on meeting nutritional needs by eating good foods (in this case, fruits and vegetables) rather than by swallowing pills.

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