Tuesday, May 31, 2011

Obsessed with those extra 10 pounds?

At Jungle Miami, the subject of weight  is a recurring theme. Being overweight, what does this mean for our health?  What is the perfect weight for a person? Our post today deals with  those extra 10 pounds many people want to loose but can not get rid off. We hope you enjoy it. Feel free to drop us a line. We appreciate it.

By Abigail Trafford

Tuesday, September 21, 2010

Ten pounds. Maybe 15! Twenty pounds? If only I could lose those 10-plus pounds -- this is the lifelong obsession of scale-watchers

 These men and women are usually not obese. They may be slightly overweight, according to current body-mass tables, but their preoccupation with the bathroom scale weighs heavily on their psyche.

And then, at a certain age, you let it go. You accept yourself as you are. You throw out the size 6 dress that's been in your closet for decades and ignore the scale. You give up on weight loss and focus on other things such as . . . wind power and grandchildren.

Are you deluding yourself?

Pounds matter. Being obese is a serious medical problem. But what about being a little overweight? Can you ignore the weight-loss police and live with a small flesh bonus as you get older?

The answer is a qualified yes. Recent studies suggest that more important than what you weigh is how healthy you are. How do you score on the fitness scale?

"I think having some excess weight and being healthy is just fine," says physician Andrew Weil, director of the Arizona Center of Integrative Medicine and author of several books on health and aging. "An accumulating body of research shows that an excess weight of 10 to 20 percent may be just fine."

Just fine to be a little fat as long as you're fit. The fit-and-fat forces scored a victory five years ago when the Harvard Medical School's Family Health Guide e-mail newsletter said that "it's possible to be heavy and fit, cardiovascularly speaking."

More recently, a 2008 report in the Archives of Internal Medicine found "a high prevalence of overweight and obese individuals who are metabolically healthy." The study followed 5,440 participants over age 20 in the National Health and Nutrition Examination Survey. More than half of the overweight adults were healthy, according to tests that measured such factors as blood pressure and cholesterol levels. A significant proportion -- almost a quarter -- of so-called normal-weight people were found to have risk factors for heart disease.

The key, according to the Cooper Institute in Dallas, is physical activity. A Cooper study published in the Journal of American Medical Association concluded that "fitness was a significant mortality predictor" independent of weight. The study followed 2,603 adults, ages 60 and older, 80 percent of them men.

Other studies are more cautious. While physical activity can reduce the risk of heart disease in overweight and obese women, "the risk is not completely eliminated, reinforcing the importance of being lean and physically active," concluded a 2008 Women's Health Study of nearly 39,000 women.

Yet overall, the research is supportive. Some studies even suggest that while the obese have the highest death rates, overweight people may have longer life expectancies than the folk who are ideally slim.



The Washington Post' s Webpage

Friday, May 27, 2011

"The Chemistry Of ...Cooking"

We at Jungle Miami always emphasize that fitness and wellness can neither be achieved nor mantained without proper nutrition. If you like cooking, even if you just like eating well, you will  love our post of today. We are publishing two articles about the chemistry of cooking. It may open a new universe for you. The science behind cooking. Enjoy our post and feel free to leave us your feedback.We appreciate it.

A Biochemist Explains The Chemistry Of Cooking

January 1, 2009

 A biochemist and cook explains that cooking is all about chemistry and knowing some facts can help chefs understand why recipes go wrong. Because cooking is essentially a series of chemical reactions, it is helpful to know some basics. For example, plunging asparagus into boiling water causes the cells to pop and result in a brighter green. Longer cooking, however, causes the plant's cell walls to shrink and releases an acid. This turns the asparagus an unappetizing shade of grey.

You love to cook, but have you whipped up some disasters? Even the best recipes can sometimes go terribly wrong. A nationally recognized scientist and chef says knowing a little chemistry could help.

Long before she was a cook, Shirley Corriher was a biochemist. She says science is the key to understanding what goes right and wrong in the kitchen.

"Cooking is chemistry," said Corriher. "It's essentially chemical reactions."

This kind of chemistry happens when you put chopped red cabbage into a hot pan. Heat breaks down the red anthocyanine pigment, changing it from an acid to alkaline and causing the color change. Add some vinegar to increase the acidity, and the cabbage is red again. Baking soda will change it back to blue.

Cooking vegetables like asparagus causes a different kind of reaction when tiny air cells on the surface hit boiling water.

"If we plunge them into boiling water, we pop these cells, and they suddenly become much brighter green," Corriher said.

Longer cooking is not so good. It causes the plant's cell walls to shrink and release acid.

"So as it starts gushing out of the cells, and with acid in the water, it turns cooked green vegetables into [a] yucky army drab," Corriher said.

And that pretty fruit bowl on your counter? "Literally, overnight you can go from [a] nice green banana to an overripe banana," Corriher said.

The culprit here is ethylene gas. Given off by apples and even the bananas themselves, it can ruin your perfect fruit bowl -- but put an apple in a paper bag with an unripe avocado, and ethylene gas will work for you overnight.

"We use this as a quick way to ripen," Corriher said. Corriher says understanding a little chemistry can help any cook.

"You may still mess up, but you know why," she said. When it works, this kind of chemistry can be downright delicious.

WHAT ARE ACIDS AND BASES? An acid is defined as a solution with more positive hydrogen ions than negative hydroxyl ions, which are made of one atom of oxygen and one of hydrogen. Acidity and basicity are measured on a scale called the pH scale. The value of freshly distilled water is seven, which indicates a neutral solution. A value of less than seven indicates an acid, and a value of more than seven indicates a base. Common acids include lemon juice and coffee, while common bases include ammonia and bleach.

WHY DOES FOOD SPOIL? Processing and improper storage practices can expose food items to heat or oxygen, which causes deterioration. In ancient times, salt was used to cure meats and fish to preserve them longer, while sugar was added to fruits to prevent spoilage. Certain herbs, spices and vinegar can also be used as preservatives, along with anti-oxidants, most notably Vitamins C and E. In processed foods, certain FDA-approved chemical additives also help extend shelf life.

This report has been produced thanks to a generous grant from the Camille and Henry Dreyfus Foundation, Inc


Chemistry in Cooking
By Gilly French

Out of the fire into the frying pan....if you've never thought about all those chemical reactions occurring every time you cook some food, here is a little enlightenment to whet your appetite....

Why does the human animal like its food cooked? After all, the earth's entire animal population had eaten its food raw for thousands of millions of years; it was only a mere million years ago that some early humans began to apply fire to a variety of objects that their ancestors had eaten raw for eons, and the new charred version prevailed. Now we enjoy cocoa and coffee beans and the crust on a roast, with sushi and steak tartare being somewhat of a novelty, an acquired taste.

Certainly cooking serves some very practicable purposes: it makes food easier to chew, more digestible, slower to go off and less likely to cause illness. The mechanical advantages may well have given rise to our smaller, less protruding jaws, compared to those of our primate relatives. But this does not explain why we should have come to enjoy cooked foods: humans didn't cook before the 'discovery' of fire, and cooked flavours are very different from the raw originals. Perhaps the answer might lie in a look at some of the chemical changes caused by cooking. This is not a simple task: hundreds of flavour molecules have been identified in, for example, cooked meat, but it is a starting point.

The modern day chemistry of food flavour dates from the discovery in the nineteen-teens of the browning reaction, also known as the Maillard reaction, which generates much of the characteristic colour and aroma of foods cooked over a flame, in the oven, or in oil. The 'simplest' browning reaction is the caramelisation of sugar, but it is not a simple reaction. Glucose produces at least a hundred different products, including organic acids, fragrant molecules and brown-coloured polymers. This takes place at a relatively low temperature of about 154°C, which is why most foods brown on the outside during the application of dry heat. Maillard reactions proper occur between amino acids (found in proteins) and sugar molecules: when these are heated together they produce, rapidly, a whole range of highly flavoured molecules that are responsible for the brown colour and distinctive taste of cooked meat. Foods that have been boiled, and moist interiors of meat and vegetables, do not exceed 100°C and will therefore look, and taste, plain. To make a rich tasting stew the meat, vegetables and flour must be browned before adding any liquid; conversely, if a cook wants to highlight natural flavours, high temperatures should be avoided. The food industry uses purified sugars and amino acids to approximate to otherwise costly flavours: for example, a well-known coffee substitute is simply a mixture of roasted wheat, bran and molasses.

High temperatures are also used, of course, to increase the rate of chemical reaction: if the rate doubles with every 10°C rise in temperature, which is a reasonable approximation, then a reaction which would normally take a day can be over in a matter of seconds. Frying, for example, is possible at temperatures of up to 250°C. The first stage of the cooking allows for heat transfer; the second, at a higher temperature, encourages Maillard reactions. At this temperature the fat is no longer a heat transfer agent and starts to influence the taste of the resulting Maillard compounds.

However, we have still not answered the question of why we should prefer our food cooked. To do this, we have to look at what happens during the caramelisation of sugar. Plain crystalline sugar has no odour. Heated to 160°C it will melt; at 168°C it begins to colour and to develop a rich aroma. At this point several hundred molecules have been formed, as the carbon, hydrogen and oxygen atoms interact with each other and with oxygen in the air at high temperatures. The volatile products include acids, aldehydes, alcohols and esters (those familiar fruity smells).

Caramelised sugar also includes ring compounds: furans (which have nutty or butterscotch aromas), and pyrones (eg maltol, which tastes of caramel) are examples.

The interesting point is that several of these flavours are contributed by chemical families of compounds that are common in nature, particularly in fruit. Alcohols, esters and the suchlike are found throughout the living world because they are all associated with the process of energy production. Cooks generate them by breaking up sugar molecules under the influence of heat; fruits generate them during the ripening process. So some of the components of the caramelised aroma would have been familiar to our ancestors in the form of fermented fruit.

The important families of aroma compounds produced in the Maillard reaction (which occurs between amino acids and sugars at a lower temperature than caramelisation) include pyrroles, thiophenes, thiazoles, pyridines and pyrazines. Several of these contribute a nutty flavour, some a 'roasted' impresion, even with hints of chocolate. And several contribute floral odours, or are reminiscent of green leaves and vegetables: flavours our ancestors would have encountered long before they had 'discovered' fire. For example the compound 2-methyl thiazole, which is reminiscent of green vegetables, is found in cooked beef. Pyrazines have been identified in molasses, coffee, green peas, Gouda cheese, red beans, asparagus and other green vegetables. The American food scientist Harold McGee, whose work has inspired this article, suggests that 'fruits probably provided our evolutionary ancestors with refreshing sensory interludes in an otherwise bland and dull diet...perhaps cooking with fire was valued in part because it transformed blandness into fruitlike richness'. Our ancestors have been encountering molecules characteristic of the roast for probably hundreds of millions of years.

Some animals, eg ants, produce their own cyclic aroma molecules by way of chemical communication - pheromones. It is suggested that, in terms of smell, there is not that much difference between us and some insects. It has been important for all animals to detect a wide variety of aroma molecules, particularly those generated by plants and other animals. McGee suggests that' our powerful response to odours may in part be a legacy of their prehistoric importance to animals, which have used them to recall and learn from experiences'.


Raymond Blanc: 'Blanc Mange', BBC books
Harold McGee: 'On food and cooking', Unwin paperbacks;
'The Curious Cook', Collier Books
T.P. Coultate: "Food, the chemistry of its components' Royal Society of Chemistry
Hooke Magazine - Issue 10


ScienceDaily's Article's Link

Camille and Henry Dreyfus Foundation INC.

The Chemistry of Cooking Webpage

Thursday, May 12, 2011

Our feet. Barefoot running, barefoot wear and more.

When you run, do you land on your heels or do you land on your toes?  When you exercise, do you train barefoot or do you wear shoes?
Everyone knows that all Jungle Animals train barefoot. As a matter of fact, we are huge on exercising barefoot. So much that last year we posted two articles dedicated to the subject.  One on training barefoot. The other one made the case for landing on our toes, when running or jogging. As part of keeping up with research regarding our feet while tracking our own results in training barefoot, we have concluded that engaging our feet barefoot in some form of physical activity is a must. The studies are showing that many ankle injuries are, the direct result of weak feet which in turn are the direct result of wearing shoes at all times. So start today, do  not delay, go barefoot as much as you can. Move your feet, engage them, they are alive and dying to workout. And if you live in Miami, and want to train your body in a natural way,  feel free to swing by Jungle.  We/ve got fun and games. All barefoot.

Enjoy our post of today.

Toe a new line: barefoot shoes

By Hilary MacGregor,
Special to the Los Angeles Times
May 9, 2011

If you live in Los Angeles or other fashion-forward places where people are eager to try new things, you have seen them: people running around in shoes that look like gorilla feet, modern ninja footwear or high-tech surf booties.

They are the newest twist on the oldest walking technology on Earth: feet.

With major shoe companies releasing a slew of these so-called barefoot shoes onto the market this spring, what began as a small movement among hard-core runners is edging into the mainstream. People are buying the minimalist shoes to hike, walk, lift weights, cross-train and water their lawns.

"It is like wearing little hobbit feet," said 42-year-old Hollywood screenwriter Matthew Sand, who wears his barefoot shoes to walk his pit bull. "It feels like walking barefoot across the grass when you were a kid, but also high-tech and cool. It is both the future and the past wrapped up with me and my toes."

The explosion in funky footwear that promises stronger muscles and better posture has some wondering whether these barefoot shoes are merely a passing fad — the Earth shoe of the 21st century — or something more lasting in the ever-expanding sports-shoe continuum.

"More than a trend, they are going to be a new category of shoe for workout enthusiasts," said Linda Sparling, general manager for FrontRunners, a longtime fitness retailer in Brentwood. "But yes, when they first came in, we had them sitting with the Earth shoes."

The most distinctive of the barefoot shoes is the FiveFingers, the individual-toed bootie with a 2-millimeter rubber sole that was dreamed up by Vibram, the renowned Italian company best known for making high-performance rubber soles for hiking boots. The patented design was introduced in 2006 and marketed for kayaking and sailing. But the shoes became a hit among barefoot runners.

The privately held company doesn't release exact sales figures, but Vibram is on track to sell 10 times more barefoot shoes this year than it did in 2009, said Georgia Shaw, marketing director for Vibram USA.

The success of FiveFingers has spawned a new generation of barefoot shoes that are less weird-looking — they lack individual slots for each toe — but are still light and low to the ground:

• New Balance just released the Minimus collection, with shoes for trail, road and life, accompanied by the motto "" (that's roughly "less equals more" for the mathematically challenged).

• Merrell, which makes hiking shoes and sandals, introduced its Barefoot Collection in March with shoes that promise to strengthen, realign and stimulate your feet.

• Fila's Skele-toes minimalist shoes evoke the original FiveFingers, but they have only four toe compartments (the last two toes slide in together). Fila promotes them "for just about everywhere" but specifically not for running.

Those who believe in barefoot shoes contend the footwear uses the body's natural biomechanics to strengthen the calf, core and foot muscles, change one's gait and improve posture. By taking the foot out of the "cast" of a regular shoe, the barefoot shoes improve the range of motion of ankles and feet. Unshielded by the thick, padded soles of running shoes, receptors in the feet receive information about surfaces and slopes, training the body to respond with balance and agility. And by eliminating the heel lift, body weight is distributed across the entire foot, promoting spinal alignment.

"I do not think it is just a flash in the pan," says Dr. Peter Langer, a podiatrist in Minneapolis and a self-described "shoe geek" who spent years working in a running shoe store. "When you put on unconventional footwear, you feel something decidedly different than a normal shoe. You realize how much sensory information you miss out on when you are wearing cushioned athletic shoes."

Putting on toe shoes requires practice. You have to spread your toes wide, wiggle in the big toe, and guide the rest of the toes in one at a time. But once you are in, they feel great, devotees say.

Wearing the shoes is like being barefoot — on steroids. With your toes pried apart, you feel like you can grip the floor like a monkey. The thin rubber sole feels more springy and safe than skin, eliminating the fear of a puncture wound or a burn. After you put them on, you realize you have never been completely relaxed when walking barefoot.

Few dispute that the trend took off with Christopher McDougall's bestselling 2009 book, "Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen." In the book, McDougall posits that running shoes may be the most destructive force to ever hit the human foot. He quotes a Harvard professor of biological anthropology who says foot and knee injuries are often caused by shoes that make our feet weak. He talks about Kalahari Bushmen who run barefoot for hours in the desert chasing antelope until the animals die.

MacDougall endorsed barefoot running — not barefoot shoes — but it didn't take long for people to figure out that FiveFingers and its offspring could make barefoot running more palatable. The shoes developed a cult-like following among MacDougall's die-hard fans, and their popularity spread by word of mouth, attracting workout fanatics looking for something different, early adopters looking for the next cool thing and those for whom returning to a simpler, more natural state of things is both a quest and a lifestyle.

Leisure Trends Group, a market research firm in Boulder, Colo., estimates that in the first three months of this year, enthusiasts bought 365,000 pairs of minimalist shoes in specialty stores devoted to running and outdoor sports. (That figure doesn't include sales by mass merchants, department stores or regular shoe stores.)



Wednesday, May 11, 2011

Type II Diabetes. No longer an "older person" disease.

The statistics are staggering. Diabetes II diagnosis in teenagers are increasing and the doctors are terrified. These are the very bad news. The good news are that with these bad news comes the awareness. And yes, there's room for change. Behavioral and eating habits changes are a most now, there is no other alternative. At Jungle Miami we do not tell parents how to raise their kids, we just want to share the information so that those interested can take action. The time is now. Please feel free to give us your feedback. We appreciate it.

Type 2 diabetes surges in people younger than 20

By Susan Brink
Kaiser Health News
Tuesday, March 22, 2011

Annie Snyder figured she'd be out of the pediatrician's office in 30 minutes, tops. Then she'd head home, tuck the medical permission for YMCA summer camp in her bag and finish packing.

But that exam last summer wasn't like any other she'd had in her 16-year, basically healthy life. Within minutes of learning the results from a urine test, she got two corroborating blood tests and was hustled off to Inova Fairfax Hospital. Lying on a gurney in the emergency room, she heard the word "diabetes" several times and knew from the urgent medical reaction that it was bad. Frightened and crying, she thought: "What have I done to myself?"

Annie Snyder
Doctors had discovered that Annie had Type 2 diabetes, a disease that is often linked to being overweight. She never made it to summer camp. By the time she came home from the hospital a week later, she knew how to inject herself with insulin and she knew that she'd have diabetes for the rest of her life.
As recently as the mid-1990s, Type 2 diabetes was almost exclusively a disease of adults. But apparently fueled by the childhood obesity epidemic, cases in people younger than 20 have ramped up from virtually zero to tens of thousands in the United States in little more than a decade. The children who have it are breaking new scientific ground: No one has any idea how they will fare over the course of a lifetime.

Annie says she was "most definitely overweight" at the time of her diagnosis, and she has already made major lifestyle changes to control the disease. By exercising and cutting back on carbohydrates, she has lost 12 pounds so far. She has reduced her need for insulin from several injections a day to just one each night, and she's hoping that soon she'll be able to put the needle aside and just use an oral drug, metformin.

Although she is the only person in her household with diabetes, Annie's diagnosis triggered a family response. Her parents got rid of the dining room table and turned that space into an exercise room, complete with a bowl of apples and artfully arranged bottles of water at the door. Everyone exercises, including her 15-year-old brother, Stephen; everyone has given up sodas and snacks, everyone eats smaller portions.

"When I see my dad exercise, I know that I've helped get him motivated," Annie says. "Before, exercise was a chore. I would sit and watch TV and eat snacks. Now, as soon as I come home, I put on my workout clothes."

A disturbing trend

Today, about 3,700 Americans under the age of 20 receive a diagnosis annually of what used to be called "adult-onset" diabetes, according to the Centers for Disease Control and Prevention. That relatively small number makes it a rare disease in children, but it represents a trend with larger ramifications.

"In a little more than 10 years, the numbers went from nothing to something," says Larry Deeb, a pediatric endocrinologist and past president of the medicine and science division of the American Diabetes Association. "And that's something to worry about."

Diabetes can cause a litany of medical woes, including heart disease, kidney failure, limb amputations and blindness. It costs the U.S. health-care system $174 billion a year, according to the National Institutes of Health.

Those statistics are grim enough when patients are in their 60s. When the diagnosis is made decades earlier, new fears are raised: Will these children suffer heart attacks in their 20s, need kidney dialysis in their 30s or go blind before they see their own children graduate from high school?

Because about 80 percent of Type 2 diabetes patients are overweight or obese, it's not surprising that patients such as Annie ask if they've done this to themselves. But there are other risk factors that no one can control: family history, ethnicity (blacks, Hispanics and American Indians have higher rates of diabetes), genetics or a mother who had diabetes during her pregnancy. Instead of wallowing in regret, doctors suggest that young patients and their parents seize the opportunity for a crash course on how to improve their health.

"I used to wear a button that said 'Stamp Out Guilt,' " says Fran Cogen, director of the Child/Adolescent Diabetes Program at Children's National Medical Center. "I try to tell people that no one caused their diabetes. I emphasize that they can make changes now."

Alarm bells are going off among those who study diabetes in children because of what they know about the adult version of the illness. More than 25 million Americans have diabetes (more than 90 percent have Type 2), according to the National Institute of Diabetes and Digestive and Kidney Diseases - but an additional 79 million have a condition called pre-diabetes, in which blood sugar levels are higher than normal but not as high as in diabetes.

Pre-diabetes isn't a disease requiring medical treatment - it's a wake-up call. A large national study showed that adults with pre-diabetes who lost 7 percent of their body weight reduced their risk of diabetes by 58 percent.

Officials are concerned that the number of children already identified as having Type 2 diabetes is just the tip of the iceberg. In a national study of 2,000 eighth-grade students from communities at high risk for diabetes, more than half of the kids were overweight or obese. Only 1 percent had diabetes - but almost a third of them had pre-diabetes, according to Lori Laffel, chief of the Pediatric, Adolescent and Young Adult Section of the Joslin Diabetes Center in Boston and a principal investigator on the study.

It's crucial, she says, to find those children before their condition progresses to diabetes so that it can be reversed by lifestyle changes, without medication.

Making progress

If there is any good news in childhood diabetes, it is that pediatricians are starting to look for it.

"It's in the news, and all over the medical literature," says Susan Conrad, a pediatric endocrinologist at Inova Fairfax Hospital. "Pediatricians are on top of it."

For example, sometimes children whose bodies are beginning to have problems regulating insulin develop a telltale dark, velvety rash around their necks. A decade ago, such a child might have been referred to a dermatologist. In addition, CDC guidelines suggest that a child with a family history of diabetes, or one whose weight is above the 85th percentile for age and sex should be screened, with blood and urine tests, for diabetes.

Family experiences made John Perrone of Winchester, Va., aware of diabetes and its consequences. John's mother, who developed gestational diabetes during all three of her pregnancies, now has Type 2 diabetes. His mother's aunt had diabetes, and by the time she died in her 70s, she was on dialysis, in a wheelchair, legally blind and had suffered two strokes.

John Perrone
John got a diagnosis of Type 2 diabetes four years ago, and he has worked hard ever since to keep the disease under control. He says he's gone from an overweight 11-year-old to a husky but fit 15-year-old. He has progressed from needing insulin injections to keeping his glucose under control with oral medication, combined with healthful eating and a lot of exercise.

He has learned enough to want to teach other kids with the disease. As an Eagle Scout project, he has developed a PowerPoint presentation aimed at youngsters. He has translated medical terms, such as glucose and glucometer, into words they understand, such as sugar and meter. He has also wanted to simplify for kids the basics of weight loss, which is so crucial for diabetes control.

"It's all about in and out, what you eat, how much you exercise," he says. "Maybe if kids understand it better, they can do it."

This story was produced through a collaboration between The Post and Kaiser Health News. KHN is a service of the Kaiser Family Foundation, a nonpartisan health-care-policy research organization unaffiliated with Kaiser Permanente.



Orginal Article

Thursday, May 5, 2011

The Human Heart and Nitric Oxide. The relationship.

The Human Heart

At Jungle Miami we already dedicated a post to the Human Heart. However, today we are posting good news on the front of Heart Disease.  We hope you enjoy it

Exercise Protects the Heart Via Nitric Oxide, Researchers Discover

Exercise both reduces the risk of a heart attack and protects the heart from injury if a heart attack does occur. For years, doctors have been trying to dissect how this second benefit of exercise works, with the aim of finding ways to protect the heart after a heart attack.

Researchers at Emory University School of Medicine have identified the ability of the heart to produce and store nitric oxide as an important way exercise protects the heart from injury.

Nitric oxide, a short-lived gas generated within the body, turns on chemical pathways that relax blood vessels to increase blood flow and activate survival pathways. Both the chemical nitrite and nitrosothiols, where nitric oxide is attached to proteins via sulfur, appear to act as convertible reservoirs for nitric oxide in situations where the body needs it, such as a lack of blood flow or oxygen.

The Emory team's results, published online in the journal Circulation Research, strengthen the case for nitrite and nitrosothiols as possible protectants from the damage of a heart attack.

The first author is John Calvert, PhD, assistant professor of surgery at Emory University School of Medicine. The senior author is David Lefer, PhD, professor of surgery at Emory University School of Medicine and director of the Cardiothoracic Research Laboratory at Emory University Hospital Midtown. Collaborators included scientists at University of Colorado, Boulder, and Johns Hopkins University.

"Our study provides new evidence that nitric oxide generated during physical exercise is actually stored in the bloodstream and heart in the form of nitrite and nitrosothiols. These more stable nitric oxide intermediates appear to be critical for the cardioprotection against a subsequent heart attack," Lefer says.

Timing is key -- the benefits of exercise don't last In experiments with mice, the researchers showed that four weeks of being able to run on a wheel protected them from having a coronary artery was blocked; the amount of heart muscle damaged by the blockage was less after the exercise period. Importantly, the mice are still protected a week after the wheel is taken away.

The researchers found that voluntary exercise boosted levels of an enzyme that produces nitric oxide (eNOS, endothelial nitric oxide synthase). Moreover, the levels of eNOS in heart tissue, and nitrite and nitrosothiols in the blood as well as heart tissue, stayed high for a week after exercise ceased, unlike other heart enzymes stimulated by exercise. The protective effects of exercise did not extend beyond four weeks after the exercise period was over, when nitrite and nitrosothiols in the heart returned to baseline.

In mice that lack the eNOS enzyme, exercise did not protect the heart from a coronary blockage, although these mice appeared to lack the ability to exercise as much as normal mice.

Another molecule that appears to be important for the benefits of exercise is the beta-3-adrenergic receptor, which allows cells to respond to the hormones epinephrine and norepinephrine. All of the beneficial effects of voluntary exercise are lost in mice that are deficient in this receptor. One of the effects of stimulating the receptor appears to be activating eNOS. Additional animal studies are currently underway in Lefer's lab to determine the potential benefit of beta-3-adrenergic receptor activating drugs following a heart attack.

The research was supported by the American Diabetes Association, the National Institutes of Health and the Carlyle Fraser Heart Center of Emory University Hospital Midtown.


Nitric oxide: A compound that is toxic but which, paradoxically, plays a number of important roles in the body, including the following:

•It acts as a vasodilator (blood vessel relaxant).
•It therefore controls blood flow to tissues.
•It regulates the binding and release of oxygen to hemoglobin.
•It thereby controls the supply of oxygen to mitochondria (cell powerhouses that generate energy).
•It kills parasitic organisms, virus-infected cells, and tumor cells (by inactivating respiratory chain enzymes in their mitochondria).
•It stimulates the production of new mitochondria.

The 1998 Nobel Prize in Medicine or Physiology was awarded to Robert F. Furchgott, Ferid Murad, and Louis J. Ignarro for their discoveries of the role of nitric oxide in cardiovascular physiology.