Health & Fitness News

Health & Fitness News: Cooked Food Grows the Brain; High-Carb Diet Contributes to Alzheimer’s; Lifting Weights Helps the Brain and Protects Against Metabolic Syndrome; Lactose Tolerance & Evolution; Tighten Your Left Fist to Perform Better

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A wide range of interesting things have popped up in health-and-fitness news. You should know about this stuff!

Cooked Food Grows the Brain:

“If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain.  We can afford more neurons, thanks to cooking.”
– Dr. Suzana Herculano-Houzel, neuroscientist, Federal University of Rio de Janeiro in Brazil

The human brain has far more neurons than our primate relatives such as apes and chimps. Relative to our body weight, we carry far more brain mass than our ape relatives, and we use far more energy to run our neurology than apes. Why? And how have we managed to acquire all the energy to manage this process over the past several hundred thousand years? It seems that the answers lie in humans cooking their food. An article from the Guardian titled Invention of cooking made having a bigger brain an asset for humans discusses the issue further. The article is informed by a study from the Proceeding of the National Academy of Sciences of the United States of America.

High-Carb Diets May Contribute to Alzheimer’s:

“Older people who load up their plates with carbohydrates have nearly four times the risk of developing mild cognitive impairment, a study out Tuesday finds.”
– USA Today

There’s more news regarding food and neurological function. USA Today reports on a recent study in the Journal of Alzheimer’s Disease indicates that a high-carbohydrate diet (as is suggested by the FDA) may contribute to early-onset dementia. Medline also reported on the study saying:

“Those who reported the highest carbohydrate intake were 1.9 times more likely to develop mild cognitive impairment than those with the lowest carbohydrate intake. Those with the highest sugar intake were 1.5 times more likely to develop mild cognitive impairment than those with the lowest intake.

Those whose diets had the highest levels of fat and protein were 42 percent and 21 percent less likely, respectively, to develop mild cognitive impairment than those with the lowest intake of fat and protein.”

The Medline report also makes the following important observation saying, “While the researchers found an association between sugar-laden, high-carb diets and mental decline, they did not establish a cause-and-effect relationship.”

I personally have lost weight by cutting carbs–particularly processed carbs such as cereal, bread, crackers, tortillas, muffins, etc–and replacing those calories with fibrous vegetables, fat and protein.  I’ve become convinced that an FDA-type high-carb diet is probably not the ideal way to eat for most people.

Lifting Weights Helps the Brain:

“Where previously we had seen positive associations between aerobic activity, particularly walking, and cognitive health, these latest studies show that resistance training is emerging as particularly valuable for older adults,”
– Dr. William Thies, chief medical and scientific officer of the Alzheimer’s Association

Of course I love any evidence that suggests lifting weights is good for you. I have particular interest in evidence that weights help us beyond simply building muscle and bone mass. Mind Your Reps: Exercise, Especially Weight Lifting, Helps Keep the Brain Sharp comes from Time. The article reports on four studies presented at the Alzheimer’s Association International Conference in Vancouver.

I’d like to know what loads are best used in preventing Alzheimer’s. Does any type of strength training prevent Alzheimers or are certain exercises better than others? What’s the minimal effective dose to derive the benefits? I hope someone is looking into these questions.

Lifting Weights Protects Against Metabolic Syndrome:

“Research has linked greater muscle strength and muscle mass to lower rates of metabolic syndrome. Since lifting weights increases muscle strength and mass, it might also help to decrease the development of metabolic syndrome.”
– Sciencedaily.com

Such a wonderful thing this weight training!  Science Daily discusses research by the National Strength & Conditioning Association that indicates lifting weights protects against metabolic syndrome. What is metabolic syndrome? The article says:

“Metabolic syndrome is a cluster of risk factors linked to increased rates risk of cardiovascular disease and diabetes. People with at least three out of five risk factors — large waist circumference (more than 40 inches for men and 35 inches for women), high triglyceride levels, reduced levels of high-density lipoprotein cholesterol (HDL, or “good” cholesterol), elevated blood pressure, and high glucose levels — are considered to have metabolic syndrome.”

The proof keeps on stacking up. Lifting weights is a staple of healthy living.  Are you currently on a strength training program?  If not, why?

Lactose Tolerance & Evolution:

“Everywhere that agriculture and civilization went, lactose tolerance came along. Agriculture-plus-dairying became the backbone of Western civilization.”
– Slate

Humans are the only animals that consume milk beyond the age of infancy. (Not all humans actually. Two-thirds of us are lactose intolerant. Still, there are a lot more humans that drink milk in their adulthood compared to other mammals.) Why is this? What makes so many of us so different from other mammals? Are there advantages to lactose tolerance? The Most Spectacular Mutation in Recent Human History is from Slate Magazine. The article discusses the speed with which this genetic mutation spread and possible theories on why it ever happened at all. There are no solid answers to the questions here, but it seems that in much of the world, civilization and lactose tolerance have gone hand-in-hand:

“The plot is still fuzzy, but we know a few things: The rise of civilization coincided with a strange twist in our evolutionary history. We became, in the coinage of one paleoanthropologist, ‘mampires’ who feed on the fluids of other animals. Western civilization, which is twinned with agriculture, seems to have required milk to begin functioning.”

There clearly seem to be some advantages to a lot of people in consuming milk and/or other dairy products. There also appear to be some real disadvantages. Read the New York Times article Got Milk? You Don’t Need It for another view of milk consumption. The article states:

“Osteoporosis? You don’t need milk, or large amounts of calcium, for bone integrity. In fact, the rate of fractures is highest in milk-drinking countries, and it turns out that the keys to bone strength are lifelong exercise and vitamin D, which you can get from sunshine. Most humans never tasted fresh milk from any source other than their mother for almost all of human history, and fresh cow’s milk could not be routinely available to urbanites without industrial production. The federal government not only supports the milk industry by spending more money on dairy than any other item in the school lunch program, but by contributing free propaganda as well as subsidies amounting to well over $4 billion in the last 10 years.”

I think the Times article raises some valid points. Clearly many of our fellow humans do fine without consuming milk as adults. The FDA guidelines insisting that we drink milk are a bit bogus, and completely influenced by the dairy industry. However, in lactose tolerant adults, I’m not sure milk is a bad thing. I haven’t been completely convinced one way or the other. I drink milk sometimes but not often. More often I consume cheese and yogurt which are fermented versions of milk.

Make a Fist to Perform Better:

“Athletes who made a fist with their left hand did better under pressure than when they made a fist with their right hand…”
– “Preventing Motor Skill Failure Through Hemisphere-Specific Priming: Cases From Choking Under Pressure,” Journal of Experimental Psychology

I find this article from the Atlantic enormously interesting. The results are in the quote above. In this study, right-handed athletes (Righties only were tested.) performed better when they made a fist in the left hand. What’s going on here? The article states:

“According to the researchers, freaking out is primarily associated with the left hemisphere of the brain, while the right hemisphere deals more with mechanical actions. Meanwhile the cortex of the right hemisphere controls movements of the left side of the body, and the left hemisphere controls the right side of the body. So they figured that if you can purposely activate the right hemisphere — in this case, by making a fist or squeezing a ball with your left hand — it will improve physical performance and draw focus away from the ruminating left hemisphere.”

Interestingly, anyone who’s learned the RKC Hard Style of pressing has learned to make a fist in the opposite non-pressing hand. The effect is powerful. You get stronger when you do this! Maybe this study indicates why.

 

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Sitting is Hazardous to Your Health

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The research showed that those who sat for long periods of time have a higher chance in their risk of diabetes, heart-disease and death.
–Diabetes Research Group, University of Leicester

It’s been suggested that you sit too much. New research from the University of Leicester backs up this claim. (By the way, there are several other studies showing the same thing.  Look here, here, here.) The study combines the results of 18 different studies and includes nearly 800,000 participants. Here are the important details.  Emphasis is mine:

“The research showed that those who sat for long periods of time have a higher chance in their risk of diabetes, heart-disease and death.  Interestingly, the results were independent of any individual physical exercise undertaken, suggesting that even if an individual meets the physical activity guidelines, their health may still be at risk if they sit for long periods of time during the day.”

I find this fascinating. You’re putting yourself at risk of death if you sit too much–even if you’re highly physically active. So in this way, sitting is like smoking. We can’t seem to out-exercise our sitting habit. So what do we do?  We need to move a little.  Researchers suggest we take frequent breaks from sitting and go move around.

It’s often easy to sit at your desk for hours on end and not even know it.  We need to be reminded to move. So here’s an idea: Set a recurring meeting on your computer’s calendar.  Make it every half-hour or hour. Label it “Get up and move around.”  Otherwise, try this series of spine mobility drills. (Because it’s not just sitting per se that’s so bad, but lack of movement that’s the problem.  You can still move while sitting at your desk.)

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Good Reads: Rethinking Sleep, A Look At “Hardcore” Workouts

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Two recent articles have caught my attention.  One comes from the New York Times; the other is a two-part piece from a blog called Fit For Real Life.  The Times article presents some new concepts on our sleep patterns.  The blog post gives a good insight on workout intensity and why more doesn’t always equal better.

Sleep

“It seemed that, given a chance to be free of modern life, the body would naturally settle into a split sleep schedule. “

I’m a big fan of sleep.  I’ve mentioned here and here that lack of sleep is tied to various ailments such as obesity and obesity-related issues like diabetes.  As I’ve always understood it, most adults need 8-9 hours of sleep a night.  (I also understand it that a small part of the adult population actually thrives on five or fewer hours of sleep per night.  I wish that were me.)  The NY Times article Rethinking Sleep has me… rethinking sleep.

The article describes the American view of bedtime and sleep and contrasts that with other cultures’ take on the same thing::

“Typically, mention of our ever increasing sleeplessness is followed by calls for earlier bedtimes and a longer night’s sleep. But this directive may be part of the problem. Rather than helping us to get more rest, the tyranny of the eight-hour block reinforces a narrow conception of sleep and how we should approach it. Some of the time we spend tossing and turning may even result from misconceptions about sleep and our bodily needs: in fact neither our bodies nor our brains are built for the roughly one-third of our lives that we spend in bed.

The idea that we should sleep in eight-hour chunks is relatively recent. The world’s population sleeps in various and surprising ways. Millions of Chinese workers continue to put their heads on their desks for a nap of an hour or so after lunch, for example, and daytime napping is common from India to Spain.”

The article goes on to cite historical variations on sleep including a mention in the Canterbury Tales of going back to sleep after her “firste sleepe.”  Further, physicians from the 16th century mention “first sleep” and “second sleep.”  Research from the NIH supports the concept that divided sleep patterns may naturally occur during the night.

Deep sleep or REM (rapid eye movement) sleep is discussed.  This is the most valuable sleep time during which our brains are highly active.  REM sleep aids cognitive function, helping us solve problems and perform at a mentally high level.  The benefits of REM sleep can be derived from any type of sleeping pattern, not just from eight straight hours of sleep.  Research suggests that brief naps can be quite useful.

The article concludes with a discussion of workplace napping.  Though napping at work isn’t allowed for most of us, the concept may be gaining traction at some places such as Google. The Army is also experimenting with the concept for soldiers who need to be ready to fight around the clocks.  Strategic naps may be essential to keep them ready for war.  The Texas Rangers baseball team has also prioritized sleep and napping for its players.

I can say from my own experience that napping during the day is way more than a luxury.  Since I’m a personal trainer I tend to be able to nap on most days of the week.  I believe it’s absolutely essential for my mental state and my overall health.  I couldn’t imagine taking another job that didn’t allow for it.  The pay would have to be MUCH higher, and I imagine I’d hate life a little for it.

“Hardcore” Workouts

“There is a finite amount of quality movement before the movement pattern breaks down, eventually degrading enough that your body is at risk for a variety of issues, including injury, if it continues.”

I found this two-parter on Twitter and I really like what the writer has to say. Her words echo my observations of many a gym member’s exercise routines and many a personal trainer’s training strategies–namely “more/harder is better.” Any idiot can exercise–or push someone else to exercise–until he or she vomits, passes out, or collapses. Easy! Swing a 24 kg kettlebell 800 times in an hour then do 100 pushups.  Run 20 x 400 m all-out sprints with one minute rest between sprints. Add more weight. Go faster. There is a better way to work out.

The articles do a very good job of explaining what happens as we fatigue, namely we don’t move as well.  We collapse at the feet, knees, hips, spine…  We set ourselves up for needless wear, tear, and injury. It’s a very good read and here are the links:

“It’s a dangerous thing to think that harder/more is better. It’s not. In fact, it’s likely what limits the long-term fitness success of many. And, when used incorrectly (as I see far too often)- it’s the fast-track to injury.”  The Poison Is In the Dose: A Look At “Hard-core” Workouts”

“So what if your movement patterns are dysfunctional? Fix them. Practice does not make perfect. Practice makes permanent. If something isn’t working don’t continue doing it: that only teaches dysfunction & permanent faulty movement patterns.”  Where There’s Smoke, Don’t Fan the Fire: Continuing Our Look at “Hard-Core Workouts”

 


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Sleep: An Essential Ingredient

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I’ve mentioned previously that lack of sleep contributes to obesity.  (Also look here and here.) Missing sleep has also been linked to increased risk of stroke and possibly depression.  Lack of sleep can predict which older adults will move to nursing homes or assisted living facilities. Finally, sleep has been shown to improve performance in swimmers, college basketball players, and college football players.

Important stuff this sleep!  Sounds like we need frequent good doses of it to be healthy and perform well.  We may be sabotaging our sleep though if we look at electronic screens at night before bed.

Recent articles in the LA Times and the Chicago Tribune discuss the disruptive effect of electronic “blue light” (such light is emitted by phones, computers and TVs) on our circadian rhythms.  We often look at these electronic devices at night before bed with the result being poor sleep and the following host of problems.  In fact, the American Medical Association released a statement on blue light saying, “that exposure to excessive light at night, including extended use of various electronic media, can disrupt sleep or exacerbate sleep disorders, especially in children and adolescents.”

Essentially, blue light is prominent during daylight.  Looking at a screen–especially one like a smartphone which is near our face–seems to make our brain think it’s day time when it isn’t.  I won’t go into all the details but they are interesting.  Have a look at the articles for more information.  As for solutions, 5 Ways to Unplug at Night for Better Sleep offers some suggestions for avoiding computers at night.

Getting away from the electronics at night is very similar to changing our eating habits to lose weight.  Reward centers in the brain are triggered by our devices and the stimulation they deliver.  It can be difficult to alter that pattern.  I find it difficult to change my ways.  I’m as guilty as anyone in looking at an electronic screen at night.  Lately I’m consciously working to turn off these devices well before I go to bed. Sometimes it’s tough.  A really good book can help. (If George RR Martin will hurry up and finish the Winds of Winter then it’ll make ditching these gadgets much easier…)

 

 


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Are All Calories Created Equal?

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“Put most simply, the fewer carbohydrates consumed, the more energy these weight-reduced people expended.”
Gary Taubes, author, Good Calories, Bad Calories

A recent Harvard University study has produced some interesting results as regards various types of eating patterns, calories, and how these all affect weight loss maintenance.   The study is discussed in two New York Times articles; one titled What Really Makes Us Fat, the other titled In Dieting, Magic Isn’t a Substitute for Science is a Q&A with a veteran obesity researcher. ABC News also analyzes the study in For Calories, It’s All About Quality Over Quantity, Harvard Study Says.

There are two main points of consideration in this discussion.  First, there’s the question, “Are all calories created equal?”  Are carb calories the same as fat and protein calories?  Are refined sugar calories the same as calories from vegetables or beans?  The second question is, “What’s the best way to stay lean once we’ve lost the weight?”

(The country is full of people who’ve lost weight but can’t keep it off.  The big secret is this: Any diet will work.  If you follow the directions, you’ll very likely lose weight no matter what diet you chose.  From paleo, to the Zone Diet, to Weight Watchers to any of the vast number of other diets, if you follow it you’ll probably lose weight.  Done and done?  No. The most difficult part has just begun.  Keeping the weight off is typically very difficult.)

What about the study?  Researchers studied 21 overweight and obese adults, starting each on a diet that helped them lose about 12-13% of their body weight. Then, to help them maintain that weight loss, the researchers put the participants on a cycle of three diets, each lasting four weeks.

One diet is of the low-fat/high-carbohydrate variety as advocated by the FDA and the American Heart Association.  This diet suggests among other things that we eat a lot of grain products, both refined and unrefined; and that we seek to reduce fat consumption at all opportunities.

The other diet was a high-fat/low-carbohydrate diet similar to the Atkins diet.  This is almost the total opposite of the previously mentioned diet.  This diet encourages fat and protein consumption and discourages grain consumption–particularly refined grains.

The third diet was based on low-glycemic foods.  This diet was sort of in between the other two. Fewer refined grains were found here and more vegetables, beans, fruit and the like.  Plus there was less fat and protein than the Atkins-type diet, but more than the low-fat diet.

What were the results?  This is from the ABC News article:

The results weren’t good news for low-fat diet aficionados. When dieters followed that plan, their bodies burned fewer calories than when they were following the low-carb or low-glycemic index diets. And the low-fat diet changed certain metabolic factors in their bodies that typically predicted weight regain.

The low-carb diet seemed to help participants burn the most calories. But it also increased certain markers of stress and inflammation in the body, such as the stress hormone cortisol, which are risk factors for cardiovascular disease and other health problems.

(I’m quite curious about this.  What’s causing the inflammation?  Is it high fat?  Is it high protein?  Is it low carbohydrate?  Is it a combination of some or all of these factors?  The Perfect Health Diet discusses research indicating that limiting protein intake can help with immune function, and that too much protein can lead to ammonia toxicity.  So that leads me to think it’s the protein that may be causing the inflammation.  Would someone please do a double-blind placebo study on this?  And please make it a long-term study while you’re at it.  Thanks in advance.)

In the end, the researchers found that the low-glycemic index diet struck the right balance for the participants. It helped the dieters burn more calories, though not as many as the low-carb diet, but didn’t seem to increase disease-causing stress markers in the body.

I like this observation as well:

“Remember the old food pyramid, with six to 11 servings per day of bread, pasta or rice at the base? In light of this article, it would seem to provide an efficient prescription for weight gain,” said Dr. Jana Klauer, a doctor in private practice in New York.

Gary Taubes, says in What Really Makes Us Fat:

The results were remarkable. Put most simply, the fewer carbohydrates consumed, the more energy these weight-reduced people expended. On the very low-carbohydrate Atkins diet, there was virtually no metabolic adaptation to the weight loss. These subjects expended, on average, only 100 fewer calories a day than they did at their full weights. Eight of the 21 subjects expended more than they did at their full weights — the opposite of the predicted metabolic compensation.

(Please note that Taubes is the author of Good Calories, Bad Calories.  He essentially proposes some of what is suggested by this study, namely that a high-carb diet–particularly one high in refined carbs–is bad and that a high-protein/high-fat diet is good for us.  His article for the NY Times highlights the good of this diet.  He doesn’t mention the following information.  Perhaps there’s a conflict of interest.)

Now, here’s a wrinkle.  Dieting, Magic Isn’t a Substitute for Science is the other NY Times article. It’s a Q&A with Dr. Jules Hirsch, emeritus professor and emeritus physician in chief at Rockefeller University, who has been researching obesity for nearly 60 years, about the state of the research. With regard to the benefits of high-fat diets, he says:

They report that people on the Atkins diet were burning off more calories. Ergo, the diet is a good thing. Such low-carbohydrate diets usually give a more rapid initial weight loss than diets with the same amount of calories but with more carbohydrates. But when carbohydrate levels are low in a diet and fat content is high, people lose water. That can confuse attempts to measure energy output. The usual measurement is calories per unit of lean body mass — the part of the body that is not made up of fat. When water is lost, lean body mass goes down, and so calories per unit of lean body mass go up. It’s just arithmetic. There is no hocus-pocus, no advantage to the dieters. Only water, no fat, has been lost.

The paper did not provide information to know how the calculations were done, but this is a likely explanation for the result.

So the whole thing might have been an illusion? All that happened was the people temporarily lost water on the high-protein diets?

Perhaps the most important illusion is the belief that a calorie is not a calorie but depends on how much carbohydrates a person eats. There is an inflexible law of physics — energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged. Calories leave the system when food is used to fuel the body. To lower fat content — reduce obesity — one must reduce calories taken in, or increase the output by increasing activity, or both. This is true whether calories come from pumpkins or peanuts or pâté de foie gras.

To believe otherwise is to believe we can find a really good perpetual motion machine to solve our energy problems. It won’t work, and neither will changing the source of calories permit us to disobey the laws of science.

So Dr. Hirsch draws a different conclusion from the researchers and the reporters.  I don’t have a solid enough command of statistics to advocate in either direction.  Both Dr. Hirsh and Gary Taubes suggest that more useful information would come from a long-term study of this type.

What seems clear though is that we should steer well clear from processed foods.  A high-fat/low-carbohydrate diet seems to best best for weight loss but also may cause an increase in the stress hormone cortisol.  The study suggests that making an extra effort to avoid fat may not be very helpful in the battle to rid our bodies of fat.  The third and possibly healthiest eating strategy revolves around a healthy intake of low-glycemic foods.  The Wiki entry on low-glycemic foods states (emphasis is mine):

There are some specific factors to look for in foods that can indicate their glycemic index: Low glycemic foods contain: Fat, Whole grains, Protein, Raw Starches, legumes, vegetables, fruits and dairy products. High Glycemic Foods contain: Refined grains, refined sugars, increased amylopectin: amylose ratio, and often high sugar fruits have a high glycemic index.

Finally, we’re often told to eat more of this that and the other.  “Eat more healthy fat.”  “Eat more fruits and vegetables.”  “Eat more whole grains.”  We’re rarely told to “Eat less” of anything. Therefore I like what Dr. Hirsch has to say about the matter:

What would you tell someone who wanted to lose weight?

I would have them eat a lower-calorie diet. They should eat whatever they normally eat, but eat less. You must carefully measure this. Eat as little as you can get away with, and try to exercise more.

 

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News On Beet Juice, Running & Evolution, Saturated Fat & Cardiovascular Disease

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I’m behind on posting and I’m trying to catch up.  There’s been a lot of interesting information to read in various publications.  If you’re a runner (and probably any other sort of endurance athlete) you definitely need to see some of this.  If you’re listening to government guidelines on saturated fat, then definitely look at the last article.

Beet juice for endurance

A number of articles have appeared lately about beet juice and its benefits for endurance athletes.  Never miss a beet is from Outside Magazine.  The article discusses two studies from Exeter University in England that demonstrated performance benefits for cyclists.  Here are the important details.  (Emphasis added is mine.):

… In 2009, a small study done at England’s Exeter University caught the attention of the fitness world. Researchers discovered that competitive cyclists who drank half a liter (about 16 ounces) of beet juice right before they got on their bikes were able to ride 16 percent longer—a massive gain in a sport where only a few percentage points of improvement can be the difference between first place and fifteenth.

Last June, a larger Exeter study backed up this rather unusual protocol: cyclists who drank half a liter of beet juice for six days were 11 seconds faster over a 2.5-mile course and 45 seconds faster over a 10-mile course. The reason: more oxygen was getting to the athletes’ muscles, thanks to molecules in the juice called nitrates. “The oxygen cost of exercising at a given speed is basically fixed,” says Andrew Jones, a professor of applied physiology at Exeter and lead author of both studies. “Only nitrate ingestion appears to improve efficiency. These effects cannot be achieved by any other known means, including training.”

It works like this: Our bodies convert nitrates into nitric oxide, a gas that causes blood vessels to relax and widen, by a process known as vasodilation. This allows more oxygen-rich blood to flow through the body—and the more oxygen reaches the muscles, the longer they’re able to perform at high intensity. Athletes have tried to trigger vasodilation with various banned substances, including hypertension drugs and erectile-dysfunction medication, for years. It now appears that simply consuming large amounts of vegetables that are high in nitrates, such as spinach, carrots, radishes, and beets—the last of which pack the biggest punch, a whopping 310 grams per 16 ounces of juice—can offer the same performance boost.

The article also discusses beta-alanine supplementation.  I haven’t used beta-alanine but recently I have been playing around with eating and juicing beets.  (I don’t juice a whole beet.  I combine about ¼ beet with other fruits and vegetables.)  I pretty much will never say that one thing causes one other thing, but since I’ve been consuming more beets, my workouts have felt really good.  Also, getting up early has been easier.  Again, I can’t say this is the only factor but I see no reason not to continue gobbling a few beets through the week.

One odd thing about beets is that they color some of your bodily excretions, meaning you may see a red tint in the toilet soon after eating or drinking beet juice.  It was kind of alarming the first time I noticed it.  Turns out it’s normal.  Despite this weird side effect, I’m giving beets a thumbs-up.

Evolution, distance running, and a controversial title for an article

Other articles have discussed the idea that human evolution and distance running are intimately intertwined.  A recent article from Slate Magazine suggests the same thing.  If nothing else, All men can’t jump: Why nearly every sport except long-distance running is fundamentally absurd sounds like fun reading.  From our Achilles tendons, to our teeth, brains, our ability to dissipate heat , gait mechanics, and even the “runner’s high,” the article suggests that we are uniquely and powerfully suited to “persistence hunting,” that is chasing down prey until it’s tired.  I think it’s an interesting theory, though I wonder if some day scientists will ruminate over the connection between our thumbs, evolution, and video games or text messaging.

Overhydration

It’s summer.  It’s hot.  We still run, bike, hike, walk, etc.  How much should we drink?  How often? Do we need to weigh ourselves before and after exercise?  Does dehydration lead directly to heatstroke? Furthermore, have you ever heard of hyponatremia, or what happens to you when you drink too much water.  (FYI, drinking too much can be far more deadly than being dehydrated.)

The issue of hydration is a pendulum that still swings around and there is confusion.  Many of us are growing gills for the amount of water we’re drinking, but this high consumption of water throughout the day seems a fairly recent thing.  Do we really need all this consumption?  How did we manage before plastic bottles?  (Watch an episode of Mad Men and you’ll see the only water anyone drank came from melted ice cubes in their cocktail.  How’d we get out of the 1950s under those circumstances?)

For more information, read the Outside Magazine article Tim Noakes on the serious problem of overhydration in endurance sports. (Why listen to Dr. Noakes?  He’s a leading exercise scientist and he’s just recently written a 439-page book called  Waterlogged: The Serious Problem of Overhydration in Endurance Sports.  He’s a very well informed guy.  All runners should read his superb book Lore of Running.)

The article covers some interesting information including how hunter/gatherers run a lot during a hunt but don’t drink until they’ve caught their prey, the history and marketing of sports drinks, and why a bit of dehydration is nothing to fear.

Here’s some background on why we think we need to drink so much when exercising.  (Emphasis is mine.):

When did we start drinking more water?

Well, the sports drink industry was involved. In 1969 a great American physiologist, David Costill, started new studies. Gatorade was just getting into the market, and he went to them and said, Listen, you produce this product, do you know if it works? Is it of any value? He said, I’ll do the studies and let’s see if it works. His focus was to try and raise money to fund his laboratory. He did the first study where he had people like Amby Burfoot—who writes the foreword for the book and won the 1968 Boston Marathon—not drinking anything. Costill had them run when they drank up to 1.2 liters per hour on the treadmill, and [then run] when they didn’t drink. When they did drink, he showed their body temperatures were much lower and he presumed that was better. But if you ask Amby Burfoot, he said he felt much better when he ran without drinking. Costill assumed then that drinking was good for you, although the study hadn’t really shown that because it wasn’t a performance trial, and all the runners found when they didn’t drink was that there were no problems associated with not drinking. The American College of Sports Medicine asked David Costill to write the first drinking guidelines, which he did in 1975. He said that runners should drink regularly during exercise, which is pretty good advice.

Then, what I discovered, which was really eye-opening, was that a single individual working for the U.S. military decided that water was a tactical weapon. That if the military could be encouraged to drink more during maneuvers, they’d have less heat stroke and less illness and they’d be more productive and could be better soldiers. It was purely his idea. It had no scientific basis at all. Two years later he published a paper supposedly saying that if the US soldiers drank 1.9 liters per hour [64 ounces] when they were exercising in the heat they would perform much better. There was utterly no concrete evidence that that was true. The problem was, his advice was embraced by the U.S. Military. They changed their drinking guidelines to say that you should now drink 1.9 liters per hour. The same people who drew up those guidelines were then invited by the American College of Sports Medicine to get involved with drawing up guidelines for runners.

The essential information first and foremost 1) let thirst be your guide, 2) over drinking is bad, and 3) anything short of severe dehydration won’t kill you.

Evidence on saturated fat and cardiovascular disease

Finally, I’ve mentioned before that perhaps we shouldn’t be as afraid of fat–particularly saturated fat–to the degree that we’ve been told.  We’ve got a little more evidence in that direction.  Saturated fat and cardiovascular disease: the discrepancy between the scientific literature and dietary advice is a recent study from the Netherlands.

Researchers evaluated three reports from leading U.S. and European dietary advisory committees with results of studies on dietary fat and cardiovascular disease as they were presented in the referenced articles.  (These committees are the sort that tell us to eat less fat for fear of contracting such ailments as heart disease.)  The findings indicate that the advice given by the committees doesn’t reflect the evidence.  The concluding statement of the abstract of the study says, “Results and conclusions about saturated fat intake in relation to cardiovascular disease, from leading advisory committees, do not reflect the available scientific literature.”  So again, perhaps we should reconsider our view of nasty old saturated fat.

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The Mathematics of Obesity

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” … the conventional wisdom of 3,500 calories less is what it takes to lose a pound of weight is wrong. The body changes as you lose. Interestingly, we also found that the fatter you get, the easier it is to gain weight. An extra 10 calories a day puts more weight onto an obese person than on a thinner one.”

– Dr. Carson C. Chow, MIT mathematician

The New York Times Science section has a fairly interesting conversation with Dr. Carson Chow, an MIT-trained mathematician who works for the National Institutes of Health (NIH) National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).  The article is titled A Mathematical Challenge to Obesity.  He’s worked with other researchers in applying a mathematical model to help describe and answer questions related to our national obesity epidemic. Several key findings are important to note in addition to the quote at the top of this page:

Also, there’s a time constant that’s an important factor in weight loss. That’s because if you reduce your caloric intake, after a while, your body reaches equilibrium. It actually takes about three years for a dieter to reach their new “steady state.” Our model predicts that if you eat 100 calories fewer a day, in three years you will, on average, lose 10 pounds — if you don’t cheat.

Another finding: Huge variations in your daily food intake will not cause variations in weight, as long as your average food intake over a year is about the same. This is because a person’s body will respond slowly to the food intake.

Dr. Chow was hired to answer the question of what caused the obesity epidemic.  He suggests that food overproduction is the culprit.  And if we have too much food then we wind up eating too much food.  He also says that changing our weight takes a very long time.  He says:

Beginning in the 1970s, there was a change in national agricultural policy. Instead of the government paying farmers not to engage in full production, as was the practice, they were encouraged to grow as much food as they could. At the same time, technological changes and the “green revolution” made our farms much more productive. The price of food plummeted, while the number of calories available to the average American grew by about 1,000 a day.

Well, what do people do when there is extra food around? They eat it! This, of course, is a tremendously controversial idea. However, the model shows that increase in food more than explains the increase in weight.

Dr. Chow was asked about practical advice.  His answer:

One of the things the numbers have shown us is that weight change, up or down, takes a very, very long time. All diets work. But the reaction time is really slow: on the order of a year.

People don’t wait long enough to see what they are going to stabilize at. So if you drop weight and return to your old eating habits, the time it takes to crawl back to your old weight is something like three years. To help people understand this better, we’ve posted an interactive version of our model at bwsimulator.niddk.nih.gov. People can plug in their information and learn how much they’ll need to reduce their intake and increase their activity to lose. It will also give them a rough sense of how much time it will take to reach the goal. Applied mathematics in action!

Dr. Chow’s final words regarding obesity may come as dreary news for people trying to lose weight and keep it off.  He says, “It’s so easy for someone to go out and eat 6,000 calories a day. There’s no magic bullet on this. You simply have to cut calories and be vigilant for the rest of your life.”

That is a very honest observation from a well-trained scientist.  Remember that the next time you see an ad for some sure-fire trendy diet or supplement.

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Running News

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“That is, once the runners were tired, their form got sloppier, theoretically raising their risk for a tibial stress fracture.”
– Runner’s World

Running while fatigued increases stress fracture risk.

I’ve discussed several times (here, here and here) the idea that if we train too hard, we’re courting injury. An article in Runner’s World gives more evidence to support this idea. The article cites recent research from Medicine & Science in Sports & Exercise. As the test subjects ran, researchers monitored several movement patterns that were indicative of tibial stress fractures.  As the subjects ran and became more fatigued, these movement patterns became exacerbated.

To me, the messages are first pay attention to your running form.  Running is a skill.  That’s why I don’t wear headphones anymore when running. Pay attention to how you run!  Second, finish your run when you still feel good.  Don’t kill yourself (except during a race) when you’re training.  Don’t be afraid to quit early or skip a day if you’re very fatigued.

“Liking to run, it seems, may have helped to make humans what they are.”
-NY Times Phys Ed

Running & evolution

Running for enjoyment is sort of a strange thing.  Non-runners will agree with me.  From an evolutionary perspective, doing something that uses up energy and exposes us to injury really doesn’t make sense.  Yet many of us love it.  Why?  It’s this question that’s discussed in a recent New York Times Phys Ed section.  Recent research in the Journal of Experimental Biology examines the matter.  Turns out humans and dogs show increased circulating endocannabinoids post run.  Walking however does not induce the same reaction.  Nor, in this experiment did running have the same effect on ferrets.  Seems that dogs and humans may have a deeply wired reward system that’s tied to running.

The question is then asked why don’t more of us run?  Dr. David A. Raichlen, a professor of anthropology at the University of Arizona, who led the study answered, “That’s the million dollar question.  It appears from our study that we have the evolutionary drive” to exercise. But modern man has learned to ignore it.

I absolutely believe we were meant to run.  And running with a dog?  There’s nothing like it in life.

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Less Sleep = More Eat

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A recent study from the Institute of Human Nutrition at Columbia University indicates that lack of sleep contributes to overeating and thus obesity.  Here is the conclusion:

The findings of this study link restricted sleep and susceptibility to food stimuli and are consistent with the notion that reduced sleep may lead to greater propensity to overeat.

What’s happening here?  Researchers found that, “Overall neuronal activity in response to food stimuli was greater after restricted sleep than after habitual sleep. In addition, a relative increase in brain activity in areas associated with reward… in response to food stimuli, was observed.”

So it seems that sleep restriction caused subjects to like food more.  They found it more rewarding.  Weird!  The take home message is obvious: Get some sleep!

In this study subjects either slept about nine hours or were restricted to only four hours.  How much sleep should you get?  Ideal sleep time may vary from person to person.  WebMD says, “Most adults need seven to eight hours a night for the best amount of sleep, although some people may need as few as five hours or as many as 10 hours of sleep each day.”  If you’re a hard-training athlete then you probably need to be on the high side of those numbers.

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A Questionable Case for Running Shoes

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The New York Times Health section discusses a study from the University of Colorado in Boulder comparing the metabolic costs of running in shoes vs running barefoot.  The results suggest that shod running is more energy efficient than unshod running.  These results deserve a few questions.  First some background on the study. 

Subjects of the study were 12 barefoot runners–runners who knew how to run barefoot in contrast to novice barefooters.  “It was important to find people who are used to running barefoot,” says Rodger Kram, a professor of integrative physiology, who oversaw the study.

These runners were then asked to run several times in a yoga sock on a treadmill or while wearing the 150 gram Nike Mayfly, a lightweight running shoe.  Then the researchers taped 150 grams’ worth of thin lead strips to the top of runners’ sock feet. By adding an equal amount of weight to the bare foot, they could learn whether barefoot running or shod running was more efficient.  The study reports these findings:

1. For every 100g (3.5oz) (the average weight of a deck of playing cards) added per foot, energy cost increases by approximately 1% whether running barefoot or shod.

2. Running barefoot and in lightweight shoes do not significantly differ in energy cost.

3. When controlling for shoe/foot mass, running in lightweight shoes requires ~3-4% less energy than running barefoot.

So it seems that wearing a shoe is a good idea if you want to conserve energy as you run.  This would be important obviously during a race.  Here are some questions and observations:

1. The positive result of wearing a shoe was seen in 8 of the 12 runners.  That means 1/3 of the subjects saw no advantage from running in shoes.  Extrapolated out to a large population that means a significant number of barefoot runners are at no disadvantage running in bare feet.  I wonder if any of them are more efficient in bare feet?

2. The study was done on a treadmill.  Treadmill running is quite different from real running.  What if the study was done on a road or trail?

3. The study looked at the Nike Mayfly.  What about other shoes?  It’s a light shoe.  Would even lighter shoes be better efficiency?

4. A commentator on the Times article made the following observation: “Flaw: the only way for the comparison to be valid is if the weight distribution of added weights were precisely the same as the weight distribution of the shoes themselves. Anyone who has ever studied the effects of mass distribution on movement would know that.”

So did the way the weight was added to the (mostly) bare feet affect the runners’ efficiency?  What if the weight was distributed differently?

5. The study enlisted experienced barefoot runners as subjects.  Alex Hutchinson of Sweat Science and Runner’s World discusses that issue:

Finally, all the runners were midfoot or forefoot strikers, both barefoot and in shoes. This condition was imposed to prevent confounding effects from comparing rearfoot to forefoot striking efficiency.

These conditions raise an important caveat. One of the proposed advantages of barefoot-minimalist running is that it automatically helps to correct overstriding — an extremely common problem among inexperienced runners. The fact that all these runners were already forefoot strikes suggests that none of them were likely overstriding, which would make them less likely to benefit from barefoot running. It’s possible that a truly ‘random’ group of runners might have been less efficient in the shod condition, because more of them would have been dramatically overstriding.

It’s good that someone has done this study.  The debate isn’t over and it’s always good to have another view.  There’s plenty more studying to be done.

One thing that I keep coming back to is the fact that the fastest runners in the world wear shoes–at least when racing.  So from the performance standpoint there seems to be some benefit to putting something on your feet.  Further, if you’re happy with you performance and enjoyment of running then you should probably stay with what you’re doing whether it’s shod or unshod.

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