What is healthy? At first blush, this may seem like an easy question to answer. However, when you actually stop and think about it, it's not easy at all. Is it the number of push-ups you can do? Is it the distance you can run? Is it how well-rounded your diet is? Or could it somehow be a combination of these things and more? The more I think about it, the more I realize that the easiest way to determine what IS healthy is to point out what I know is NOT healthy. Starvation diets, foods high in bad cholesterol, sedentary lifestyles, trans fat, simple sugars, lack of sleep, and so on, and so on. This list, of what it means to be unhealthy, is very easy to compile. But, this whole thing gets a bit tricky when you honestly don't know if something is healthy or if it isn't. Thanks to smart advertising and widely spread half-truths, it's sometimes nearly impossible to make sense of it all.

Fortunately, voices of discontent are starting to be heard, and food manufacturers are coming clean about their so-called "healthy" offerings. We now know that just because a bread is labeled as being Wheat Bread, all that really means is that it contains some portion of wheat flower (the rest is made of enriched wheat and then colored with a caramel to give it that healthy brown look). The key is to look for bread that is listed as being 100% Whole Wheat or Whole Grain. The same goes for many juices. For years, juice manufactueres made it seem like giving your kids their product was a healthy choice. But, we now know that so many of the juices in your supermarket contain the same amount of sugar (if not more) than some brands of soda. As for fitness, that's just as confusing. For years, people suggested starving yourself and then doing aerobics for four hours a day. Fast forward to today, and it's almost common knowledge that starvation diets don't work (and, in fact, typically lead to an increase in weight gain) and that extremely long periods of aerobic exercise is overly taxing to the heart and can lead to the catabolization of muscle.

So, I go back to my original question: What is healthy? In my opinion, healthy is following a positive lifestyle; one that is manageable, as stress-free as possible, involves the eating of several small meals throughout the day, incorporates a workout program that is realistic and consistent, and always ends with a good night's sleep. Am I right? I'm not sure, but I know that nothing I just mentioned seems to be wrong.

It's that time of the week again. Yup, it's time for me to drop a little knowledge on you and offer up my Exercise of the Week. If you'll recall (if if you'll simply go back in the archives), last week's exercise was The Plank. While this was a static exercise, this week we'll get you a bit more mobile.

It's called the Spider-Man Crawl, and it's a great exercise to get your heart rate going while at the same time stimulating several of your primary and ancillary muscle groups. A word of caution: Besides the typical exercise disclaimer about consulting your physician before beginning any exercise regimen, I also suggest that you perform this exercise in a wide open space. Due to the amount of "climbing" you will be doing, performing the Spider-Man Crawl in a crowded gym may not be the best idea. With that out of the way, let me tell you how the Spider-Man Crawl is done ...

Now that we have told you all the great heart health and weight loss benefit there is to bouncing on a mini-trampoline -- we are here to tell you not all mini-trampolines are alike.

According to JB Berns, the creator of the Urban Rebounding Program, the mini-trampolines found in stores are not build to withstand the demands put on it during the repetitive bouncing exercises of rebounding.

For those who have become bored with workout routines, or suffer from joint and muscle stress that can result from various forms of exercise, rebounding is an easy and fun alternative. Berns offers a mini-trampoline built to last, a stabilizer bar, and exercise videos as part of the Urban Rebounding Program.

A martial arts black belt in karate and fitness expert named one of America's top 10 personal trainers by Fitness magazine, Berns states that rebounding offers a "challenging cardiovascular workout without excess stress on the heart, muscles and joints. that allows the body to work harder, for a longer period of time without absorbing the shock and stress of hard-surface workouts."

To learn more about the As Seen on TV Urban Rebounding Program, visit the company's website online.

Recent U.S. research has confirmed that fat tissue is a safely dependable source of stem cells for potential smooth muscle cells that cardiologists can utilize to regenerate and repair damaged hearts. Harvesting adipose fat cells is also simpler and less invasive for the patient than collecting stem cells from the brain or bone marrow.

Published in the Proceedings of the National Academy of Sciences, the study shows these fat stem cells have the ability to transform into smooth muscle cells -- which contract and relax just as normal muscle does -- and have the ability to help the heart beat and pump blood. Transplants are possible using a patients own fat cells, avoiding the need for any anti-rejection drugs. The cells are called multi-potent and have the ability to become a variety of different cells and tissues -- however, they are not as flexible as embryonic stem cells.

Life-long survivors of childhood cancers have the benefit of celebrating their success in winning the battle -- however, a new Dutch study found that many who had undergone treatment in their youth experienced the development of heart abnormalities in their 30s and 40s.

The cancer treatment in question are chemotherapy drugs called anthracyclines, which have contributed to the current 80 percent long-term survival rate of children with cancer. Anthracyclines appear to damage heart muscle cells, and continue to do so even after treatment has stopped. The most commonly developed heart problems are diastolic dysfunction, when the left heart chambers don't ever fully relax -- followed by systolic dysfunction, when the left chambers fail to pump correctly. It is estimated that cancer survivors who undertook these treatments are eight times more likely to develop these heart dysfunctions.

According to the researchers, some childhood cancer patients are currently receiving lower doses of anthracyclines accompanied by heart protective medication. It is recommended that these cancer surviving patients follow a more heart healthy lifestyle, and that their doctors be on the alert for the more subtle signs of heart problems.

To live a long and healthy life, the answer can be simple. Eat less and exercise more. Not only does this help avoid weight issues such as obesity that can lead to heart disease, it also helps maintain muscle mass as the body ages. A new study found that a diet light in calories not only supports muscle function, it can also lengthen life span by 35 percent.

Researchers from the University of Calgary studied muscle mass, function and life span in elderly rats fed a diet 40 percent lower in calories from childhood. They found that these rats displayed muscle mass and function similar to 20-year-young rats, and only experienced a 20 percent drop in muscle mass as they aged, with no decline in function.

Note: The researchers DO NOT advise that we, as humans, cut our dietary intake by 40 percent-- which could possibly be dangerous to our muscle mass. They DO recommend eating a healthy diet without over-indulging, and exercising regularly to maintain muscle mass and function.

Mad cow disease, or prion disease, is ultimately a fatal disease that creates swiss cheese sponge-like holes in the brain, but before the infected person dies from prion disease, they can suffer neurologic abnormalities, dementia, memory loss, hallucinations, and seizures -- a kind of madness. In the United States, if you lived in the United Kingdom for three months or more during the outbreak of mad cow disease from 1980 to 1996, you are asked not to donate blood. In the United Kingdom, the restriction on blood donation is much stricter -- only individuals born after the outbreak can donate blood.

But mad cow disease is not confined to the UK. Since the much documented outbreak in the UK, mad cow disease has been found in other countries around the globe. Several factors make mad cow disease disturbing. One, scientists know that the disease can be transmitted across species through the consumption of tainted meat from a diseased animal. Two, they believe it can take decades after infection before symptoms become evident -- like a ticking time-bomb waiting to explode at some unknown time. Prions diseases include scrapie in sheep, mad cow disease in cattle, chronic wasting disease in deer and elk, and new variant Creutzfeldt-Jacob disease in humans. Right now, there are 140 human cases. The median age of death of people infected in Great Britain, where most cases have occurred, is 28 years of age.

New research has come to light that prion diseases can travel through the bloodstream and infect heart muscle leading to heart failure. In laboratory tests involving mice, researchers discovered that the prion protein decreased the heart's ability to pump blood.    

"Until now, prion disease has been thought of as a chronic neurological condition," says Scripps Research Professor Michael B. Oldstone, M.D., who led the research. "Our study has shown, however, that it can have other manifestations, therefore expanding the types of conditions it could cause."

Researchers have found that sildenafil citrate, known as Viagra, minimizes by 50 percent the chemically-induced stimulation of increased rate and pumping force of the heart caused when stress hormones in the body rise. Stress hormones can rise under emotional or exercise stress, or when there is heart failure. Originally prescribed for erectile dysfunction (ED) in men, Viagra appears to have a direct effect in protecting the heart against the short-term intense assault of stress hormones. The benefit Viagra gives in controlling heart function kicks in when stress hormones increase, but has little affect on the heart under normal conditions.

According to the researchers of this study, separate research published last year in the journal Nature Medicine showed that, in mice, Viagra could reverse the negative effects on heart muscle weakened by heart failure and enlargement, a condition called hypertrophy. "But we had no firm evidence as to whether or how this therapy might work in the human heart. Our latest research provides firm evidence this drug does indeed have an important impact on the heart," states cardiologist David Kass, M.D., professor at The Johns Hopkins University School of Medicine and its Heart Institute.

"Knowing more about the effects of sildenafil on heart function will allow for  safer evaluation of its use as a treatment for heart problems," says Kass. "Until now, it was widely thought that drugs like sildenafil had no effects on the human heart and that its only purpose was vasodilation in the penis and the lungs." He believes the results of this study will open the door to further studies into the potential benefit of Viagra on the heart. You can find more information about the study here.

Magnesium is an important yet overlooked mineral integral to a healthy heart. The average American diet only provides about half of the recommended daily allowance, which is 400 mg. Magnesium helps keep the heart beating smoothly, aides in maintaining healthy blood pressure, and relaxes arterial muscle tissue.

Deficiency of magnesium in heart and arterial tissues can result in a muscular spasm that causes an oxygen-supplying artery to clamp shut, resulting in sudden death. This incidence is known as ischemic heart disease, or a suffocation of the heart.  Hardened arteries, which lead to heart attacks, can also be caused by a lack of magnesium-- without which the body cannot properly assimilate calcium.

Excellent sources of dietary magnesium include dark chocolate, nuts, avocados, milk, spinach and other leafy green vegetables, lentils, wheat germ, bran, and some meat. Dietary supplements, including combo calcium-magnesium capsules, can be found in most health food stores.