Sarcopenia: muscle loss is the new bone loss?

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As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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For an article I’m working on, I’ve been digging through the literature on sarcopenia, the age-related loss of muscle mass that most of us face starting in our 30s. I’ve found several conflicting estimates of how much muscle you can expect to lose, with a high end of 1-2% per year starting in your fourth decade (from this paper). That’s a lot more aggressive than I’d expected. I get the sense that it’s one of those problems whose implications we’re just now beginning to grasp — so I was interested to see this article by Andrew Pollack in the New York Times, which offers a good introduction to the topic:

Bears emerge from months of hibernation with their muscles largely intact. Not so for people, who, if bedridden that long, would lose so much muscle they would have trouble standing.

(Nice lede!)

Why muscles wither with age is captivating a growing number of scientists, drug and food companies, let alone aging baby boomers who, despite having spent years sweating in the gym, are confronting the body’s natural loss of muscle tone over time.

Comparisons between age groups underline the muscle disparity: An 80-year-old might have 30 percent less muscle mass than a 20-year-old. And strength declines even more than mass…

Much of the article focuses on attempts to agree on a clinical definition of the condition — which would then make it possible for drugmakers to win approval from regulators for drugs to treat it. But the key point for me is:

Researchers involved in the effort say doctors and patients need to be more aware that muscle deterioration is a major reason the elderly lose mobility and cannot live independently.

In other words, I need to start doing my push-ups again. Soon.

Beyond beet juice: L-arginine also boosts endurance

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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Andrew Jones, the man behind the beet juice fad of 2009, has more performance-enhancing revelations in a study just released online in the Journal of Applied Physiology. He found that taking the supplement L-arginine produced very similar effects to beet juice: by reducing the “oxygen cost of exercise,” it allowed subjects to last 20% longer in a ~10-minute cycle to exhaustion (11:47 versus 9:22 for controls) in a placebo-controlled double-blind trial. They estimate that’s equivalent to a boost of 1-2% in a fixed-distance race. (Abstract here, press release here.)

What’s significant here is that L-arginine acts in basically the same way as beet juice. Beet juice contains nitrate, which the body converts to nitric oxide, which has a number of effects such as dilating blood vessels and lowering blood pressure, ultimately allowing the body to perform more work from the same amount of oxygen. L-arginine is also converted by an enzyme to nitric oxide, producing the same cascade of effects — and, as the researchers note, the performance boosts observed in the two studies are very similar, giving them confidence that they really do understand what’s happening inside the body.

This is by no means the first L-arginine study — there have been a number of attempts to use it for performance enhancement, with conflicting results. Previous studies have generally given the supplement on a chronic basis — a little bit each day, or even several times a day. In this case, the researchers opted for one big dose, taken an hour before exercise, to make sure that nitric oxide availability really was elevated during the exercise bout. (They used 500mL of a drink called Ark 1, containing 6 g of L-arginine. There are no disclosures in the paper about who paid for the study.) This change may explain why they saw such a clear result compared to earlier studies.

So what’s next? According to the press release, “the researchers are hoping to find out whether combining the two methods could bring an even greater improvement in athletic performance.” In the meantime, perhaps L-arginine will prove to be a more user-friendly option than beet juice. Here’s what Amby Burfoot reported about one world-record-holder’s abortive try:

Two days before the ING New York City Marathon, I asked Paula Radcliffe if she actually drank beet juice. This moved her to stage one: silly giggles. And an embarrassing response. “I tried it once,” she said, “but most of it came out the other end.

Is exercising with your iPod making you stupid?

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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Just read an interesting article by Matt Richtel in the New York Times. The nut: Researchers believe that our brains need downtime in order properly assimilate new information and memories, but we now have so many devices to fill every moment with distraction and titillation that we may be compromising our ability to learn.

It’s 1 p.m. on a Thursday and Dianne Bates, 40, juggles three screens. She listens to a few songs on her iPod, then taps out a quick e-mail on her iPhone and turns her attention to the high-definition television. Just another day at the gym…

But scientists point to an unanticipated side effect: when people keep their brains busy with digital input, they are forfeiting downtime that could allow them to better learn and remember information, or come up with new ideas. Ms. Bates, for example, might be clearer-headed if she went for a run outside, away from her devices, research suggests.

This is a new wrinkle in a very familiar debate about the pros and cons of exercising with headphones or other electronic devices. I have to confess that, though I’ve read all the literature about how music can pump you up and so on, I’m in the shrinking minority that prefers their exercise unwired. And my reasons, on an intuitive level, fit with what Richtel describes in this article. My life is pretty hectic, and I’m bombarded by a constant stream of information and stimulus. Most of us are these days, I think. I’d love to say that, when I head out for a run, it gives me a chance to think in peace, to have those deep insights that require uninterrupted meditation. But really, I usually just space out. If these researchers are right, though, that period of mental blankness could play a key role in the epiphanies I have later on, since my brain has been busy consolidating and organizing information.

Of course, there’s a flip side. It’s undeniable that lots of people really like exercising with music and/or TV. And that’s got to be better than not exercising at all, as Richtel’s article also acknowledges:

Some researchers say that whatever downside there is to not resting the brain, it pales in comparison to the benefits technology can bring in motivating people to sweat.

“Exercise needs to be part of our lives in the sedentary world we’re immersed in. Anything that helps us move is beneficial,” said John J. Ratey, associate clinical professor of psychiatry at the Harvard Medical School and author of “Spark: The Revolutionary New Science of Exercise and the Brain.”

But all things being equal, Mr. Ratey said, he would prefer to see people do their workouts away from their devices: “There is more bang for your buck doing it outside, for your mood and working memory.”

The trouble with acupuncture studies

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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Tara Parker-Pope has an interesting article in the New York Times about a recent study on acupuncture for pain relief, and more generally about the difficulties in testing acupuncture (and other forms of “traditional” or “integrative” medicine) using standard Western research methods.

The study tested acupuncture versus a sham treatment (that also involved needles, but inserted in the “wrong” places and not as deeply) in 455 patients suffering from knee arthritis. Both groups experienced relief — their pain decreased by one point on a scale of 1 to 7 compared to controls who received no treatment at all. This is consistent with a series of earlier studies suggesting that “inserting needles in or around an area of pain may have caused a ‘super placebo’ effect, touching off a series of reactions that changed the way the body experienced pain.”

The NYT article is worth reading for the discussion of what can and can’t be tested with traditional blinded clinical trials. And then there’s the even harder question: if the effects of acupuncture are essentially a placebo, but a powerful one, then what do we do? After all, the results — pain relief — are surely more important than the mechanism. But what if we establish once and for all that it’s a placebo. Does that mean its effectiveness will disappear? Is it better to remain ignorant so that treatments like acupuncture will work?

Pre-run stretching doesn’t affect injury rate

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

In the “I didn’t know they did research” department, U.S.A. Track and Field just released the results of a study on pre-run stretching. They recruited 1,400 runners through their website for a randomized, prospective study in which half the volunteers stretched before running and the other half didn’t. Over the next three months, 16% of the runners got injured, with no difference whatsoever between the stretching and non-stretching groups.

You can’t read too much into a volunteer, self-reported study like this, but if you drill a little further into the data, there are some interesting wrinkles. Age, sex, weekly mileage, flexibility and level of competition all had no effect on injury rates. High BMI and previous history of injury, on the other hand, both led to a higher probability of injury.

Most interestingly, people who normally stretch before runs but were assigned to the non-stretching group actually doubled their risk of injury. There’s not really enough detail in the study to understand why this happened, but it underscores an important message that applies not only stretching, but to other hot topics like running shoes: If you’re running happily without injury problems, don’t change what you’re doing!