Archive for July, 2009

Fatigue: It’s all in your mind. Or tastebuds.

Fatigue

Conventional wisdom among most physiologists used to be that fatigue was a biochemical phenomenon. You get tired from running, for example, because of a buildup of lactic acid in one’s legs — or maybe because the muscles don’t have enough oxygen.

But what explains, then, the awesome sight of marathon participants who sprint the final hundred yards of a 26.2 mile race — an event that otherwise slowed them to a walk (or a crawl) until the “finish line” came into view? If fatigue is something that can be explained by reference to an anatomy and physiology textbook, how and why do people often finish exhausting exercises faster than at any other point in the workout?

Because the mind matters.

From Gretchen Reynold’s fantastic story in this past Sunday’s NYT Magazine, “Going All Out: Can Your Brain Fight Fatigue?“:

Recently, researchers in England discovered that simply rinsing your mouth with a sports drink may fight fatigue. In the experiment, which was published online in February in the Journal of Physiology, eight well-trained cyclists completed a strenuous, all-out time trial on stationary bicycles in a lab. The riders were hooked up to machines that measured their heart rate and power output. Throughout the ride, the cyclists swished various liquids in their mouths but did not swallow. Some of the drinks contained carbohydrates, the primary fuel used during exercise. The other drinks were just flavored, sugar-free water.

Phys Ed

By the end of the time trials, the cyclists who had rinsed with the carbohydrate drinks — and spit them out — finished significantly faster than the water group. Their heart rates and power output were also higher. But when rating the difficulty of the ride, on a numerical scale, their feelings about the effort involved matched those for the water group.

In a separate portion of the experiment, the scientists, using a functional M.R.I., found that areas within the brain that are associated with reward, motivation and emotion were activated when subjects swished a carbohydrate drink. It seems that the brains of the riders getting the carbohydrate-containing drinks sensed that the riders were about to get more fuel (in the form of calories), which appears to have allowed their muscles to work harder even though they never swallowed the liquid.

Time to hit the trails for a little mindful running.

play, think…
J.R. Atwood

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July 22, 2009 at 6:31 pm Leave a comment

The changing state of play

Two recent news stories signal the changing state of play among children and youths, and reflect the value of physical education in our schools…

1) Layton, Utah will become the first American municipality west of the Mississippi River to install an electronic playground. “The playground includes electronic versions of games such as Capture the Flag and tug-of-war. Layton’s city parks planner says the goal is to get the video game generation back to the playground so it becomes more active.” More information about this project can be found here.

2) Massachusetts state law requires schools to provide physical education to all student at every grade level. However, in the city of Boston alone, more than 7,700 elementary school students and 4,800 high school students at 27 different schools (proportional to one out of every four students in Boston) “went without phys-ed instruction during the 2007-08 academic year.” Corrective action has been ordered. More from the Boston Globe here.

play, think…
J.R. Atwood

July 17, 2009 at 3:12 am 1 comment

Pushing the limit

From the NYT: “Surviving the Death Race,” a 24-hour “adventure race through mental and physical Hell” staged in Pittsfield, Vermont.

July 15, 2009 at 10:59 pm 1 comment

To eat or not to eat? New study provides evidence that maintaining a chronic caloric deficit improves health and extends life

As this ScienceDaily article explained a few weeks ago, “Experiment after experiment confirms that a diet on the brink of starvation expands lifespan in mice and many other species.”

Could humans actually benefit from a permanent diet that left them chronicaly deficient of the number of calories to maintain a healthy weight? Many of these studies were conducted with animals (relatively) far-removed from the human species, genetically speaking, such as worms and rats  — though speculation on this topic goes back to 2001, when the LA Times wrote a headline supposing that “Low-calorie diet given to mice may be key to longevity in humans.” Many people who have converted to a restricted calorie diet testify to having better cardiovascular health, and have been reported to live longer, than their peers who consume a “regular” amount of calories, but there has yet to be any experimental studies with humans that validate these anecdotes.

Today, however, the journal Science published the results from a much-anticipated longitudinal and experimental study about the health effects of a restricted calorie diet in primates. The title of the article, which can be accessed here, explains the main takeaway: “Caloric restriction delays disease onset and mortality in Rhesus monkeys” (Colman et al.).

The BBC (“Proof Mounts on Restricted Diet“) and LA Times (“Permanent diet may equal longer life“) provide fantastic summaries of the research. From the BBC:

Seventy-six rhesus monkeys were involved in the trial, which began in 1989 and was expanded in 1994.

Half had their diets restricted, half were given free rein at feeding time.

The rate of cancers and cardiovascular disease in dieting animals was less than half of those permitted to eat freely.

While diabetes and problems with glucose regulation were common in monkeys who ate what they wanted, there were no cases in the calorie controlled group.

In addition, while most brains shrink with age, the restricted diet appeared to maintain the volume of the brain at least in some regions.

In particular, the areas associated with movement and memory seemed to be better preserved.

And from the LAT:

“It adds to the evidence piling up that caloric restriction, independent of thinness, is a healthy way to stay alive and healthy longer,” said Susan Roberts of the Human Nutrition Research Center on Aging at Tufts University, who wasn’t involved in the study. “Less diseases in old age has to be something most everyone wants.”

Is caloric restriction the solution?

“Mild caloric restriction is beneficial to everybody,” said Dr. Luigi Fontana, a medical professor at Washington University in St. Louis.

In his examinations of people who have been practicing caloric restriction for an average of 6 1/2 years, Fontana found their heart function was equivalent to those of people 16 years younger.

Though the regimen sounds grueling, it is hardly a starvation diet, experts said.

It typically begins with an in-depth assessment to determine how many calories an individual needs to consume to maintain a healthy weight. Then that number is shaved by 10% to 30%.

Fourteen deaths in the control group were attributable to age-related diseases, compared with five such deaths among the animals that ate 30% fewer calories, according to the study.

The rates of cardiovascular disease and pre-cancerous cell growths were twice as high in the control group compared with the reduced-calorie group.

The researchers also noted that although five of the control monkeys became diabetic and 11 were classified as pre-diabetic, all the calorie-restricted animals remained diabetes-free.

Brain scans revealed significantly less atrophy of gray matter in the monkeys that ate less.

They even looked less wrinkled and flabby.

In all, the monkeys on caloric restriction “appear to be biologically younger than the normally fed animals,” the researchers wrote in their report.

The researchers and authors, though, caution against using this study as justification for a dramatic change in human diet.  As the BBC article closes,

“Monkeys may be a close relation but there are significant differences which means not everything we see in them can be translated to humans,” said Catherine Collins, spokeswoman for the British Dietetic Association.

“And there should be some serious reservations about cutting calories so dramatically, particularly for anyone under the age of 30. Any such diet would need to be very balanced to avoid malnutrition, and it would be a long-term commitment.”

And would a restricted calorie diet mean having to give-up all of our favorite indulgences? Maybe not. Richard Weindruch, senior author of the study,  “has started a company to create drugs that would provide the same health benefits without the need for extreme dieting.”

Note: The NYT had a story on the Rhesus monkey and restricted calorie research a few years ago. It’s also worth a read and can be found here.

Also, New York magazine published a provocative cover story title “The diet to end all diets,” in which one of their writers documents his two-month experiment on an extreme restricted calorie diet. Read “The fast supper” here.

play, think…
J.R. Atwood

July 10, 2009 at 5:59 pm 2 comments

Spinning Music, Mixes and Workouts

Spandex… Spinning… And shameless self-promotion.

I have been teaching indoor cycling/spinning classes for more than five years and am often asked for copies of my workouts and music mixes — spinningmixes.wordpress.com is intended to be a place to share this information.

In recent years, I’ve been posting a new routine every month, and recently published a new workout and music mix for the month of July. Even if you’re not into spinning (which provides a fantastic low-impact, high-intensity cardio workout in a dynamic group environment), I invite you to browse the blog, download some new music, forward the mixes to your athletic-minded friends, and to leave a comment with your own favorite “power songs.”

Power 10 Spinning!
J.R. Atwood

July 8, 2009 at 1:19 pm 18 comments

This week’s must-reads: the psychology of randomness, basketball’s full-court press, and a reflection on the ideas of fairness and merit in education

In “The Triumph of the Random: From banking to baseball, winning streaks owe much to the laws of chance,” Leonard Mlodinow, a teacher of randomness at Caltech, explains the psychology of curious phenomena and why Joe DiMaggio’s “epic 56-game hitting streak” may have been a fluke. (This is one of the best and more interesting articles I have read that explains and applies statistics.)

Also discussed, why looking at a five-year history of a company’s performance is a poor indicatory of an organization’s health (to say nothing of its likelihood of future performance):

Suppose we undertake an analysis of the resources, effort and ability of all the companies in the Fortune 500 and determine that every company has the same 60% chance of success in any given year. If we observe all the companies over a period of five years and the underlying probability of success were reflected in each company’s results, then over the five-year period every company would have three good years.

The mathematics of chance indeed dictate that in this situation the odds of a company having zero, one, two, four or five good years are lower than the odds of having three. Nevertheless it is not likely that a company will have three out of five good years—because there are so many of those misleading outcomes, their combined odds add up to twice the odds of having exactly three. That means that of the 500 companies, two-thirds will experience results that belie their underlying potential. In fact, according to the rules of randomness, nearly 50 of the companies will have a streak of either five good years, or five bad years, even if their corporate capacities were no better or worse than their counterparts’. And so if you judged the companies by their five-year results alone, you would probably over- or underestimate their true value.

Why — if you truly wanted to know which baseball team was superior — you might need to restructure the World Series as a best-of 269-game series:

In sports, the championship contenders are usually pretty evenly matched. But in baseball, even if one assumes that the better team has a lopsided 55/45 edge over the inferior one, the lesser team will win the seven-game World Series 40% of the time. That might seem counterintuitive, but you can look at it as follows. If you play a best-of-one game series, then, by our assumption, the lesser team will win 45% of the time. Playing a longer series will cut down that probability. The problem is that playing a seven-game series only cuts it down to 40%, which isn’t cutting it down by much. What if you demand that the lesser team win no more than 5% of the time—a constraint called statistical significance? The World Series would have to be the best of 269 games, and probably draw an audience the size of that for Olympic curling. Swap baseball for marketing, and you find a mistake often made by marketing departments: assuming that the results of small focus groups reflect a trend in the general population.

And an explanation for our tendency to attribute meaning to random acts:

We find false meaning in the patterns of randomness for good reason: we are animals built to do just that. Suppose, for example, that you sit a subject in front of a light which flashes red twice as often as green, but otherwise without pattern. After the subject watches for a while, you offer the subject a reward for each future flash correctly predicted. What is the best strategy?

A nonhuman animal in this situation will always guess red, the more frequent color. A different strategy is to match your proportion of red and green guesses to the proportion you observed in the past, that is, two reds for every green. If the colors come in some pattern that you can figure out, this strategy will enable you to be right every time. But if the colors come without pattern you will do worse. Most humans try to guess the pattern, and in the process allow themselves to be outsmarted by a rat. (Those trying to time the market lately might wish they had let the rat take charge.) Looking for order in patterns has allowed us to understand the patterns of the universe, and hence to create modern physics and technology; but it also sometimes compels us to submit bids on eBay because we see the face of Jesus in a slice of toast.

***

In “How David Beats Goliath,” the ubiquitous Malcolm Gladwell offers a fascinating explanation of how underdogs have — and can consistently! — triumph over physically superior and more-talented opponents. (Tip to basketball coaches and players: apply a full-court press on defense! Always!) A short excerpt from an absolute “must read!” article about the advantages of rule-breaking:

David’s victory over Goliath, in the Biblical account, is held to be an anomaly. It was not. Davids win all the time. The political scientist Ivan Arreguín-Toft recently looked at every war fought in the past two hundred years between strong and weak combatants. The Goliaths, he found, won in 71.5 per cent of the cases. That is a remarkable fact. Arreguín-Toft was analyzing conflicts in which one side was at least ten times as powerful—in terms of armed might and population—as its opponent, and even in those lopsided contests the underdog won almost a third of the time

In the Biblical story of David and Goliath, David initially put on a coat of mail and a brass helmet and girded himself with a sword: he prepared to wage a conventional battle of swords against Goliath. But then he stopped. “I cannot walk in these, for I am unused to it,” he said (in Robert Alter’s translation), and picked up those five smooth stones. What happened, Arreguín-Toft wondered, when the underdogs likewise acknowledged their weakness and chose an unconventional strategy? He went back and re-analyzed his data. In those cases, David’s winning percentage went from 28.5 to 63.6. When underdogs choose not to play by Goliath’s rules, they win, Arreguín-Toft concluded, “even when everything we think we know about power says they shouldn’t.

***

My final selection to this week’s selection of articles of interest is a reflection on the idea and role of merit in our education system — and in American society. In “Life, Liberty and the Pursuit of Aptitude,” Walter Kim asks whether “our merit-based ideas of fairness get us what we deserve?”

All systems that seek to rank human beings according to “merit” will inevitably fall short of fully accounting for what merit consists of in the real world. As such, these systems, like our Constitution, should be subject to to amendment from time to time, since no definition of merit lasts forever.

play, think…
J.R. Atwood

July 6, 2009 at 3:21 am 1 comment


Jason R. Atwood

I'm an avid trail runner and doctoral student at U.C. Berkeley who studies motivation and the relationship between the mind and body. This blog is a forum to share research, news, and musings about these topics of interest. More

Play is the beginning of knowledge.

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