The bare facts about heat stroke

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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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In case summer ever decides to start, here’s an article on heat stroke from Gretchen Reynolds of the New York Times. The best line, relating to how heavy clothing can increase risk:

“I’m all in favor of naked practice sessions,” [University of Connecticut researcher Douglas] Casa says. Unfortunately, sunburn also is thought to have an impact on your abilitity to dissipate heat.

Other than that, nothing particularly surprising in the article — unfortunately, there’s no quick fix or miracle cure for heat stroke. It’s a matter of caution, acclimating to hot weather (especially if, say, an unusually cold and wet summer has limited your exposure to hot days), and looking out for warning signs like dizziness and confusion. Another interesting point: while hydration is important, it’s perfectly possible to get heat stroke even if you’re fully hydrated.

VO2max (and lactate threshold) testing: what is it and why get it?

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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This week’s Jockology column in the Globe and Mail compares the benefits of VO2max and lactate threshold testing:

The question

What is VO2max and should I have mine tested?

The answer

VO2max is a term that surfaces whenever feats of great endurance are in the news, such as the gruelling Tour de France that wrapped up last weekend. It refers to “maximum oxygen uptake,” the amount of oxygen you’re able to deliver to your muscles when you’re exercising at your hardest.[read on…]

I’ve been tested a couple of times, once as part of an exercise physiology study and once purely for interest because a friend of mine, Dr. Gerald Zavorsky, offered to test me. But I’m not sure how many people take advantage of the commercial services offering testing. I’d be interested to hear from anyone who’s done it — why they did it, what they got out of it and so on.

Preventing knee injuries with mental training

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)

***

A pair of new studies from the University of Michigan offers an interesting take on how to prevent knee injuries like the ever-common ACL (anterior cruciate ligament) tears. What they’ve found is that the “wrong move” that leads to the injury may result as much from fatigue in your central nervous system as from physical fatigue in the knee or joint itself. That means we may want to change the kinds of preventive exercises we do to focus more on our brains and reflexes. Continue reading “Preventing knee injuries with mental training”

How to swim fast pt. 2: Train, because Jaked and LZR are banned

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)

***

The big news in swimming is that the buoyant polyurethane suits that have made a mockery of world records for the past 17 months — first Speedo’s LZR, and more recently the Jaked suit — have finally been banned by international authorities, effective starting in 2010. To put this in context:

In the Olympic individual events, only four world records remain from the pre-2008, pre-polyurethane era: the men’s 400- [UPDATE: uh, scratch that: Ian Thorpe’s record just went down] and 1,500-meter freestyles, and the women’s 100 breaststroke [that one’s gone too] and 100 butterfly [and so’s that one].

This is the right decision, and a big relief for anyone who wants the competition to be among athletes rather than the R&D arms of big companies.

[T]hey enabled swimmers without an ideal physique or impeccable conditioning to be more competitive. Squeezed into the corset-like suit, a muscled and stocky body is as streamlined as a long and lean one; a soft abdomen as effective as six-pack abs. “The thing that’s really hurt more than anything else is the whole suit situation has devalued athleticism,” [U.S. swim coach Dave] Salo said. “A lot of kids who aren’t in very good shape can put on one of these suits and be streamlined like seals.”

Of course, that doesn’t prevent some whining from athletes who like the suits:

“Basically, when we roll back, racers are going to hurt a lot more than they hurt currently, which is not something I’m looking forward to,” [U.S. swimmer Matt] Grevers said.

The big question now: what to do about the world records that have been set over the pact few years. After all, it could take a long time to eradicate them with normal suits.

How many calories in that brownie: Why food labels are wrong

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)

***

Fascinating article in New Scientist about the “calorie delusion.” Turns out that the number of calories listed on food labels can be very misleading, depending on the type of food:

[A]ccording to a small band of researchers, using the information on food labels to estimate calorie intake could be a very bad idea. They argue that calorie estimates on food labels are based on flawed and outdated science, and provide misleading information on how much energy your body will actually get from a food. Some food labels may over or underestimate this figure by as much as 25 per cent, enough to foil any diet, and over time even lead to obesity.

The standard figures assume that we get about 4 calories per gram of carbohydrate and protein, and 9 calories per gram of fat. But because of the way we digest food, more recent research suggests that’s an overestimate by about 20 percent for protein, and 25 percent for dietary fibre. Other factors like the texture of the food, whether it’s cooked, and even whether it’s chopped or ground up, also make a big difference.

In a study published in 2003, for example, a team led by Kyoko Oka at Kyushu University in Fukuoka, Japan, investigated the effect of food texture on weight gain. They fed one group of rats their usual hard food pellets, while a second group received a softer version. Both pellets had exactly the same calorie content and flavour. The only difference was that softer ones were easier to chew. After 22 weeks, the rats on the soft food diet were obese and had more abdominal fat. “Food texture might be as important a factor for preventing obesity as taste or food nutrients,” Oka and his colleagues concluded (Journal of Dental Research, vol 82, p 491).

The bottom line, as the article points out: don’t pick a brownie full of refined flour and sugar over a granola bar full of nuts and whole grains just because the label says the brownie has fewer calories.