By Dr. Mercola

Dr. Mercola has been passionate about health and technology for most of his life. As a doctor of osteopathic medicine, he treated many thousands of patients for over 20 years. In the mid 90’s he integrated his passion for natural health with modern technology via the internet and developed a website, Mercola.com to spread the word about natural ways to achieve optimal health.

A recent study looked at the heart function of 40 elite long-term endurance athletes after four endurance races of varying lengths.

By measuring cardiac enzymes and taking ultrasounds, the researchers were able to measure the acute effects of extreme exercise on the heart.

They found that:

Right ventricular (RV) function diminished after races

Blood levels of cardiac enzymes (markers for heart injury) increased

The longer the race, the greater the decrease in RV function

12 percent of the athletes had scar tissue in their heart muscle detected on MRI scans one week after the race

The authors of the study concluded that, “intense exercise causes dysfunction of the RV, but not the LV.

Although short-term recovery appears complete, chronic changes may remain in many of the most practiced athletes.”

Dr. John Mandrola, M.D. writes:

“I’m not an alarmist, but this study scares me … RV damage is not good.

Diseases that affect the RV tend to cause electrical instability that may increase the risk of sudden death…

Exercise remains the most effective and safest means to prevent and treat heart disease. The overwhelming majority exercise far too little. In fact, I believe the US suffers from severe exercise-deficiency. That said, however, accumulating data suggest–at least–the possibility of an upper limit of what the human heart can sustain.”

I agree. Although exercise reduces your cardiovascular risk by a factor of three, too much vigorous exercise, such as marathon running, actually increases your cardiac risk by seven, according to a study presented at the Canadian Cardiovascular Congress 2010 in Montreal. This is a powerful lesson to anyone who engages in large amounts of cardio exercise, because as it turns out, excessive cardio may actually be counterproductive.

The Marathon Myth

The answer is to exercise correctly and appropriately, and making certain you have adequate recovery, which can be as important as the exercise itself. Part and parcel of a healthy exercise regimen is variety, but beyond that, there’s now overwhelming evidence indicating that conventional cardio or long-distance running is one of the worst forms of exercise there is. Not only have other studies confirmed the disturbing findings above, but they’ve also concluded it’s one of the least efficient forms of exercise.

New research supports the concept that you are not maximising your efforts when you’re running marathons. On the contrary, the evidence is stacking up against conventional cardio. Here are several additional studies confirming the health-harming effects of long-distance running:

A 2006 study screened 60 non-elite participants of the 2004 and 2005 Boston Marathons, using echocardiography and serum biomarkers. Just like the featured study above, it too found decreased right ventricular systolic function in the runners, caused by an increase in inflammation and a decrease in blood flow.

Research by Dr. Arthur Siegel, director of Internal Medicine at Harvard’s McLean Hospital, also found that long-distance running leads to high levels of inflammation that may trigger cardiac events.

A 2006 study found that long-distance running leads to abnormalities in how blood is pumped into your heart.

In a study published in the Journal of Applied Physiology, researchers recruited a group of extremely fit older men. All of them were members of the 100 Marathon club, meaning athletes who had completed a minimum of 100 marathons. Half of these lifelong athletes showed some heart muscle scarring as a result – specifically the men who had trained the longest and hardest.

Recently published in the journal Circulation, this animal study was designed to mimic the strenuous daily exercise load of serious marathoners over the course of 10 years. All the rats had normal, healthy hearts at the outset of the study, but by the end most of them had developed “diffuse scarring and some structural changes, similar to the changes seen in the human endurance athletes.”

Research Now Shows You Can Gain Greater Benefits in Less Time

Clearly, when it comes to exercise, more is not always better. As I’ve learned in more recent years, the opposite is oftentimes true. Granted, this warning does not apply to the vast majority of people reading this, as most people are not exercising nearly enough. But it’s still important to understand that not only is it possible to over-exercise, but focusing on the wrong type of exercise to the exclusion of other important areas can actually do you more harm than good. Even if you don’t end up dying from sudden cardiac death during a race, years of marathon running can take a toll on your ability to achieve optimal health.

Research emerging over the past several years has given us a deeper understanding of what your body requires in terms of exercise, and many of our past notions have simply been incorrect.

For example, there’s compelling evidence showing that high-intensity interval training, which requires but a fraction of the time compared to conventional cardio, is far more efficient, and more effective. You can literally reap greater rewards in less time. The same can be said for the super-slow form of weight training, which mirrors many of the health benefits of high-intensity interval training. Research published in the journal Progress in Cardiovascular Diseases recently concluded that the best fitness regimen is one that mimics the movements of our hunter-gatherer ancestors, which included short bursts of high-intensity activities, but not long-distance running.

Interval Training – A Much Better Cardio Workout

According to fitness expert Phil Campbell and author of Ready Set Go, getting cardiovascular benefits requires working all your muscle fibers (you have three different types) and their associated energy systems. Curiously enough, this cannot be achieved with traditional cardio… Your heart has two different metabolic processes:

The aerobic, which require oxygen for fuel, and

The anaerobic, which do not require any oxygen

Traditional strength training and cardio exercises work primarily the aerobic process. High-intensity interval training, such as Peak Fitness, on the other hand, work your aerobic AND your anaerobic processes, which is what you need for optimal cardiovascular benefit. According to Campbell:

“Most exercise programs today are built based upon a very incomplete picture of the physiology of your body. For example, long slow cardio, “calories in, calories out,” would be a perfect way to look at the body if it were all slow-twitch fiber … [but] there are three muscle fiber types: slow, fast and super-fast … both those types of fast-twitch fibers are essentially 50 percent of your muscle fibers that don’t get recruited until you add a velocity of movement.”

…Continued in Part Two…

Read more: http://www.care2.com/greenliving/is-long-distance-running-bad-for-your-heart.html#ixzz1qKiYXefK