Archive for February, 2012

Sweat Science blog moving to Runner’s World site

February 8th, 2012

[Update: Comments made between October 2012 and April 2013 are missing due to a web hosting problem. My apologies for the missing entries! -AH]

[Update: the new RSS feed for the blog is]

So… big news. As of today, the Sweat Science blog is moving over to Runner’s World. All new posts will appear at It’s exciting news for me, and I think it’s good news for readers too, as I’ll explain below.

What will I find over at Runner’s World?
Don’t worry, it’s not turning into a running blog. In fact, the content will be exactly the same – the broad theme remains “the science of fitness,” encompassing everything from neuroscience to nutrition, with (I admit!) a particular focus on endurance sports. The blog won’t be going through any editorial process – no one from RW will be suggesting topics or overseeing what I write. (On the flip side, that means there will still be typos, unfortunately!)

Why move?
The move coincides with another career shift: starting in the April issue, I will be writing a monthly column in the print edition of Runner’s World, and will also become a contributing editor for the magazine. The column will be entirely separate from the Sweat Science blog; it’s called Fast Lane, and will focus on more applied training ideas for serious runners.

No, really… why?
Hey, let’s be honest: the other part of the reason is money. I’ll now be able to make part of my living from this blog – which is why I think the move is good news for readers. Sweat Science has grown far beyond what I anticipated when I started it three years ago, and now takes up a considerable amount of time. I’ve resisted accepting advertising and making quid pro quo arrangements, in part because I’m not confident that I’d manage to say what I really think about fitness products and research if I’m also accepting money or free stuff from the people selling them. Getting a paycheque from Runner’s World allows me to keep spending time reading and dissecting the literature without establishing direct relationships with advertisers whose products I write about. (Yes, I realize that RW will have ads from, for example, shoe companies – but the extra degree of separation makes a big difference to me.)

Oh yeah, I guess I’ll probably have to switch to American spelling. So maybe I am a sell-out after all…

What now?
I hope you’ll update your bookmarks, browsing habits, RSS feeds, and whatever other newfangled social media tools bring you to this site. As I’ve mentioned elsewhere, this blog has changed my own practice of journalism for the better: by the time I write about a neat new piece of research for a newspaper or magazine these days, chances are I’ve been directed to an interesting new angle or a relevant counterargument by someone in the comments section of the blog. I sincerely appreciate all those contributions, and hope they’ll continue.

Thanks again for reading, and hope to see you at the new address. In fact, the first post is already up, on how — contrary to conventional wisdom — running may protect your lungs from air pollution.

Worms, booze and life extension

February 7th, 2012

An odd little study from researchers at UCLA, just published in PLoS ONE (full text here; press release here) looks at how alcohol extends lifespan in worms. In fact, these particular worms double their lifespan when you given them a little booze. But “little” is the operative word here: they used ethanol diluted by a factor of 20,000:

“The concentrations correspond to a tablespoon of ethanol in a bathtub full of water or the alcohol in one beer diluted into a hundred gallons of water,” Clarke said.

And more wasn’t better: a little more doesn’t provide any additional lifespan benefits; a lot more produces “harmful neurological effects” and kills them. So the optimal dose is a tiny amount.

What does this mean for humans? Very little, at this point. Still, it’s hard not to compare the results to all the human studies that have found longevity benefits for very moderate amounts of alcohol consumption (i.e. a glass a day), but not for larger amounts. It’s still not clear whether the apparent benefits relate to the ethanol itself, or to all the antioxidants and fancy compounds found in wine (and possibly beer). Could humans be affected by a mechanism similar to what’s going on in these worms?

“While the mechanism of action is still not clearly understood, our evidence indicates that these 1 millimeter–long roundworms could be utilizing ethanol directly as a precursor for biosynthesis of high-energy metabolic intermediates or indirectly as a signal to extend life span. These findings could potentially aid researchers in determining how human physiology is altered to induce cardio-protective and other beneficial effects in response to low alcohol consumption.”

Time to go pour a tablespoon of ethanol in my bathtub, I guess!

When VO2max isn’t max

February 6th, 2012

This week’s Jockology column in the Globe and Mail takes a closer look at the recent study that produced “supermax” VO2max values by changing the test protocol, suggesting that the VO2max plateau isn’t really a physical maximum:

Eventually, your muscles can no longer get enough oxygen. It’s an immutable physical limit that kicks in during any sustained physical exercise and tells your body: “This fast – but no faster.”

At least, that’s the theory we’ve been working with since 1923. But a controversial new study from researchers on three continents suggests that the famous “VO2max” – the maximum amount of oxygen that you’re able to deliver to your muscles during hard exercise – isn’t really a maximum at all. Your heart and lungs don’t call the shots after all; your brain does. […]

As usual, Trish McAlaster has a nice graphic that illustrates what’s going on with the new test:

Less sleep makes food more rewarding

February 3rd, 2012

There’s plenty of evidence that lack of sleep puts you at higher risk of gaining weight. A new Swedish study in the Journal of Clinicla Endocrinology and Metabolism (press release here, abstract here) offers some new insights with fMRI brain scans:

We already know that obese people tend to find food more rewarding, as indicated by brain scans of activity in the anterior cingulate cortex:

Higher activation of this brain region has been found in obese compared with normal-weight subjects when anticipating food, suggesting that the rewarding quality of food is enhanced in obesity.

The study took a dozen volunteers and kept them up all night, then looked at their brain’s response to images of food. Compared to after a normal night of sleep, they observed the same changes that you see in obesity: stronger activation of the ACC, indicating higher dopamine signalling. You want more food than normal, because food makes you feel better than it normally would. As the graph on the right shows, those with the biggest changes in brain activity also reported the biggest appetite.

A study like this, where the subjects stayed up all night, isn’t a great way of figuring out what happens in the much more common situation of, say, getting half an hour less sleep than you need, night after night for weeks or months on end. But other studies looking at appetite hormones like ghrelin and leptin suggest that the effects are similar: too little sleep = greater appetite relative to energy needs.

Of course, this leaves us with a riddle: if you have to get up an hour early to fit your workout in, do the benefits outweigh the downsides? That depends on a  lot of things, but my general sense is that exercise has so many benefits that it’s still worthwhile. The real answer, of course, is to organize your life so that you can sleep enough and get some exercise.

Muscle biopsies show massage fights inflammation

February 2nd, 2012

Very cool new study on massage, from Mark Tarnopolsky’s group at McMaster (abstract here, press release here). Massage is one of those interventions that’s very difficult to study objectively — people like the feel of massage, you can’t blind them, and the outcomes you’re interested in are usually very subjective. But this study does a very good job.

The details: 11 volunteers exercised to exhaustion (about an hour or more on an exercise bike with gradually increasing pace) to induce muscle damage. Then, after a 10-minute break, one of their legs was massaged as follows:

(i) 2 min of effleurage, a light stroking technique delivered with a moderate pressure; (ii) 3 min of petrissage, a firm motion involving compression and subsequent pressure release from the muscle; (iii) 3 min of slow muscle stripping, consisting of repeated longitudinal strokes of ~40 s; and (iv) an additional 2 min of effleurage.

The leg to be massaged was randomly selected, and no one except the massage therapist knew which leg had been massaged until after the results were analyzed.

So how to figure out what the massage did? They took three muscle biopsies from each leg: one at rest, one immediately after the massage, and one 2.5 hours after the massage. Then, because they didn’t know exactly what to expect, they did an untargeted whole-genome analysis to figure out which genes reacted differently between the massaged and non-massaged leg. The result:

[W]hen administered to skeletal muscle that has been acutely damaged through exercise, massage therapy appears to be clinically beneficial by reducing inflammation and promoting mitochondrial biogenesis.

How and why does this happen? The researchers suggest that “mechanical stretch or strain during massage treatment” activates the relevant signalling pathways. In fact, they suggest, the mechanism may be essentially the same as conventional anti-inflammatory drugs. Which is very cool. They also checked the rate of glycogen restoring and lactate clearance in the muscles; neither were improved by massage (which, in the case of lactate, we already knew).

So what does this tell us? Massage does something. Do these acute signalling changes translate to a clinically significant difference in muscle recovery a day later? Impossible to say for now. Is effleurage or petrissage more effective than one of those self-massage devices you can buy from late-night informercials, or than a foam roller? Who knows. But it’s a very good start.