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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.