I think we can all agree that when it comes to exercise, more is not always better. 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. A study performed in 2011 by the European Heart Journal 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 function diminished after races. ~ Blood levels of cardiac enzymes (markers of heart injury) increased. ~ The longer the race, the greater the decrease in RV function. ~ 12% 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 Right Ventricular, but not the Left Ventricular. Although short term recovery appears complete, chronic changes may remain in many of the most practiced athletes.
This study is a little scary huh? Right Ventricular damage is not good. Diseases that effect this portion of the heart tends to cause electrical instability that may increase the risk of sudden death. 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.
Exercise remains the most effective and safest means to prevent and treat heart disease. The overwhelming majority still exercise far too little. I believe the US suffers from sever exercise deficiency. This is only a note of awareness into one of the more popular means of exercise, "long distance running."
The real answer is to exercise correctly and appropriately, and making certain you have adequate and proper recovery. This can be just as important as exercise itself. Part of a healthy regimen is variety. I could go through a load of overwhelming evidence indicating that conventional cardio or long distance running is one of the worst forms of exercise there is. Here are a couple that confirm the health alarming effects of long distance running: ~ A 2006 study screened 60 non-elite participants of the 2004 and 2005 Boston Marathons, using echocardiography and serum bio-markers. 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. ~ 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 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. In the next post I will dive into what the research says about exercise based on our human physiology.
References. Seigel, A. (2001). Effect of marathon running on inflammatory and hemostatic markers. American Journal of Cardiology, 88(8), 918-920. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11676965 Burns, A. (2011). Exercise-induced right ventricular dysfunction and structural remodelling in endurance athletes. European Heart Journal. http://dx.doi.org/10.1093/eurheartj/ehr397