Canadian Running magazine: Jan.-Feb. issue

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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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A belated note that the Jan.-Feb. issue of Canadian Running magazine is on newsstands now. My top picks for this issue: a hilarious back-page essay by Canadian miling legend Harvey Mitro on runners’ obsession with stopping their watches, and an interesting piece by nutrionist Matthew Kadey on which foods it’s worth paying more for, and which you can skimp on. (For example, he argues in favour of dark poultry meat — a policy I’ve long advocated in order to save $1.19 at Swiss Chalet!)

And, of course, there’s my regular Science of Running column, tackling hyponatremia, deep-water pool-running, “dynamic compression” technology, and other topics.

When is it too hot to run a marathon?

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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Ever since the sun-baked fiasco of the 2007 Chicago Marathon, there’s been renewed discussion about how to figure out when it’s unsafe to hold a major road race. In the February issue of Medicine & Science in Sports & Exercise, the medical director of the Twin Cities Marathon, University of Minnesota med school prof William O. Roberts, has an interesting analysis of this question — and he ends up with pretty conservative recommendations.

What’s interesting about his analysis is that he takes a population-level approach: instead of sticking a few representative subjects on a treadmill, he analyzes two large data sets. First, he looks at eight unexpectedly hot races that results in either mid-race cancellations or “mass casualty events” (where the number of patients overwhelms the medical resources available in a community), and calculates the “wet bulb globe temperature” (WBGT) at start time. He finds that WBGT above about 21 C (70 F) is an indicator of serious trouble for marathons at northern latitudes with participants who haven’t acclimatized to the unexpectedly hot weather.

Then he does a more specific analysis for the Twin Cities marathon, plotting the percentage of marathon starters who were either unable to finish or required medical attention as a function of WBGT. (The graph, along with the full text of the paper, is available here.) In this case, he finds that a start WBGT above 20.5 C (69 F) is trouble.

These conclusions contrast with American College of Sports Medicine guidelines allowing starts with WBGT up to 28-30 C (82-86 F) — guidelines based on tests of young military recruits. The key problems are (a) the average recreational marathon runner is not G.I. Joe, and (b) the participants in a northern (latitude greater than 40 degrees) marathon will be less prepared for a hot day than people who live in hot places.

This probably isn’t welcome news for race directors — no matter how hot it is, few participants are going to take kindly to a decision to cancel something they’ve spent months training for. But knowledge is good — and even if a race isn’t cancelled, this is the kind of information that runners themselves should take into account when they’re facing adverse weather conditions.

(A note on WBGT: it’s a scale that takes into account the effects of humidity and solar radiation, as well as air temperature, on humans. As a very rough rule of thumb, if humidity is above about 50%, WBGT will be higher than air temperature; if humidity is below 50%, WBGT will be less than air temperature.)

Pressure during penalty kicks makes you fixate on the goalkeeper

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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When you kick a soccer ball, it tends to go where you’re looking. The problem is that when you’re anxious, you tend to fixate on threats — the goalkeeper, in this case — and consequently kick it straight at him. That’s the message from an interesting University of Exeter study published last month, which I just noticed thanks to Dan Peterson’s blog.

The players wore special glasses which enabled the researchers to record precise eye movements and analyse the focus of each footballer’s gaze and the amount of time spent looking at different locations in the goal. The results showed that when anxious, the footballers looked at the goalkeeper significantly earlier and for longer. This change in eye behaviour made players more likely to shoot towards the centre of the goal, making it easier for the keeper to save.

The solution? “Research shows that the optimum strategy for penalty takers to use is to pick a spot and shoot to it, ignoring the goalkeeper in the process,” the study’s author says. And to do that, you need to practice, so that the skill becomes so ingrained it no longer requires conscious control, as discussed in this Jockology column.

Platelet-rich plasma therapy: just another placebo?

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)

***

“Platelet-rich plasma therapy” is a pretty hot topic these days, what with sports doc Anthony Galea (who has performed the technique on countless professional athletes) under the microscope because of a criminal investigation, and recreational athletes getting in on the action too. It’s a pretty simple concept: extract the patient’s blood, spin it in a centrifuge to concentrate the platelets (and ditch the red blood cells), then re-inject the platelets at the injury site (e.g. Achilles tendon, tennis elbow, other tendon injuries).

There have been some encouraging studies over the past few years, but a discordant note has just emerged in the Journal of the American Medical Association. Dutch researchers injected 54 patients with Achilles tendon problems, and followed up with them over the course of 24 weeks. Sure enough, the patients improved on measures of pain and activity level — the problem is, half of them were injected with a placebo, and there were no statistical differences between the two groups.

Needless to say, this doesn’t prove that the procedure doesn’t work. But it should throw a bit of cold water on hopes that it would be a miracle treatment.

Yoga reduces cellular inflammation marker

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)

***

I get a lot of questions about the benefits of yoga, and they’re very difficult to answer for a number of reasons. One is that yoga is so diverse — different types of yoga (and different teachers and different classes) offer very different stimuli. Even within a given type of yoga, it’s a very “mixed” activity, working on flexibility, strength, as well as possibly cardio and mental state. Given these challenges, it’s not surprising that there’s a lack of solid research into the benefits of yoga, so I’m always happy to see a study that looks at something more quantifiable than “sense of wellness.”

With that preamble, here’s a press release about a new Ohio State study, which found that women who practiced yoga had lower amounts of a cell called interleukin-6 (IL-6) in their blood. IL-6 is a cytokine (a type of cell produced by the immune system) associated with inflammation, which has been implicated in heart disease, stroke, diabetes and other diseases. Great!

If you look more carefully at the study, though, it’s not quite the smoking gun we’re looking for. For one thing, it wasn’t a “prospective” study that observed changes over time. Instead, they took one group of yoga experts, and compared them to another group of yoga novices. The experts had lower levels of IL-6, but of course it’s hard to know whether the personality (or physical) traits that had led these people to become yoga masters also had other effects that put their bodies under lower stress. The study also looked at how the subjects’ IL-6 levels responded to stressful tests like cold-water immersion and hard math problems. Again, the yoga experts did better, but that doesn’t really tell us anything definitive.

Surprisingly, one test that showed no difference between the novices and the experts was in their physiological response to a yoga session. Here’s what Lisa Christian, one of the researchers, had to say about that:

“Part of the problem with sorting out exactly what makes yoga effective in reducing stress is that if you try to break it down into its components, like the movements or the breathing, it’s hard to say what particular thing is causing the effect,” said Christian, herself a yoga instructor. “That research simply hasn’t been done yet.”

Which is basically what I was saying at the top of this post. Yoga is complicated — and for now, the research looking for its “secret” remains pretty sketchy.