By Dr. Mercola
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."
"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 maximizing 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."
If you don't actively engage and strengthen all three muscle fiber types and energy systems, then you're not going to work both processes of your heart muscle. Many mistakenly believe that cardio works out your heart muscle, but what you're really working is your slow twitch muscle fibers. You're not effectively engaging the anaerobic process of your heart.
Fortunately, Peak Fitness type exercises do address these fibers and metabolic systems. As an added boon, when you perform Peak Fitness exercises properly, you will also increase your human growth hormone (HGH), which increases your muscle growth and effectively burns excessive fat. HGH also plays an important part in promoting your overall health and longevity.
In the case of Peak Fitness exercises, less truly is more, as you can get all the benefits you need in just a 20-minute session performed twice a week. In fact, you should not do Peak Fitness exercises more than three times a week. If you do, you may actually do more harm than good - similar to running marathons. Because while your body needs regular amounts of stress like exercise to stay healthy, it also needs ample recuperation, and if you give it more than you can handle your health will actually begin to deteriorate. So it is really crucial to listen to your body and integrate the feedback into your exercise intensity and frequency.
When you work out, it is wise to push as hard as you possibly can a few times a week, but you need to wisely gauge your body's tolerance to this stress, and give your body time to recuperate.
Super-Slow Resistance Training
While I've been recommending high-intensity anaerobic training (Sprint 8) using an elliptical machine or a recumbent bike, Dr. McGuff is a proponent of high-intensity interval training using weights. In a recent interview, he discussed both high-intensity anaerobic-type training, and high-intensity super-slow weight training, which can achieve many of the same results using weights instead of a recumbent bike or elliptical. We also discussed the importance of recuperation.
I've been recommending doing Peak Fitness exercises three times a week, but after doing that myself for about a year, I gradually felt that the frequency was too much for me. I just felt too fatigued between sessions. Dr. McGuff's interview convinced me to make some changes to my routine, so I'm currently in an experimental phase. While I'm still doing Peak Fitness two to three times a week, I reduced the intensity by about five percent. I'm also incorporating McGuff's Super Slow strength training.
He believes you only need 12 minutes of Super Slow type strength training once a week to achieve the same growth hormone production as you would with Peak Fitness! Intensity is key, and, according to Dr. McGuff, when the intensity is really high, the frequency may need to be reduced in order for it to be really productive.
How to Perform Super-Slow Weight Lifting
By aggressively working your muscle to fatigue, you're stimulating the muscular adaptation that will improve the metabolic capability of the muscle and cause it to grow. McGuff recommends using four or five basic compound movements for your exercise set. These exercises can be done using either free weights or machines. The benefit of using a quality machine is that it will allow you to focus your mind on the effort, as opposed on the movement.
Dr. McGuff recommends the following five movements:
- Pull-down (or alternatively chin-up)
- Chest press
- Compound row (A pulling motion in the horizontal plane)
- Overhead press
- Leg press
Here's a summary of how to perform each exercise:
- Begin by lifting the weight as slowly and gradually as you can. The first inch should take about two seconds. Since you're depriving yourself of all the momentum of snatching the weight upward, it will be very difficult to complete the full movement in less than 7-10 seconds. (When pushing, stop about 10 to 15 degrees before your limb is fully straightened; smoothly reverse direction)
- Slowly lower the weight back down
Repeat until exhaustion. (Once you reach exhaustion, don't try to heave or jerk the weight to get one last repetition in. Instead, just keep trying to produce the movement, even if it's not 'going' anywhere, for another five seconds or so. If you're using the appropriate amount of weight or resistance, you'll be able to perform four to eight repetitions)
Immediately switch to the next exercise for the next target muscle group, and repeat the first three steps. When done in this fashion, your workout will take no more than 12 or 15 minutes. For more information about Super-Slow resistance training, please see my interview with Dr. McGuff.
The take-home message here is that one of the best forms of exercise to protect your heart is short bursts of exertion, followed by periods of rest. You can do this Sprint 8-style using an elliptical machine or recumbent bike, or you can do it using McGuff's Super-Slow resistance training strategy. Ideally, you'll want to do a little bit of both.
By exercising in short bursts, followed by periods of recovery, you recreate exactly what your body needs for optimum health. Heart attacks don't happen because your heart lacks endurance. They happen during times of stress, when your heart needs more energy and pumping capacity, but doesn't have it. So rather than stressing your heart with excessively long periods of cardio, give interval training a try.
Most importantly, during any type of exercise as long as you listen to your body you shouldn't run into the problem of exerting yourself excessively. And, with interval training, even if you are out of shape you simply will be unable to train very hard, as lactic acid will quickly build up in your muscles and prevent you from stressing your heart too much.