Do you dread going to the gym for what feels like hours at a stretch? Or do you avoid working out altogether because you just don’t have the time? Then what I’m about to tell you should be music to your ears: when it comes to exercise, less is more.
It’s becoming increasingly clear from the recent flurry of scientific studies that overdosing on exercise can have detrimental effects on your health. Too much exercise, particularly long bouts of cardio such as marathon and triathlon training, can do more harm than good—particularly to your heart.
While most Americans would be well served to exercise more, there’s no need to work out for more than 45 minutes at a time, and if you exercise effectively, your workouts should be even shorter, which I'll be discussing in a moment.
Getting your heart pumping and your body sweating with regular cardio exercise provides multiple benefits. As your heart rate rises:
- Your heart pumps more efficiently
- The amount of oxygen in your blood increases
- Your body’s ability to detoxify improves
- Your immune system is activated
- Endorphins increase, elevating your mood
This is just the tip of the iceberg when it comes to the benefits of exercise, but there is a cutoff point beyond which exercise can actually harm your body.
Recent studies are giving us a much better understanding of exercise physiology, and many of our past notions have been turned upside-down, in terms of how long and how hard to push yourself before the benefits of exercise turn into damages.
As you probably know, I am a passionate advocate of exercise and staying fit. But too much of a good thing can have the opposite effect of what you want.
Overdosing on Exercise Can Backfire
Exercising excessively or incorrectly can backfire on your health in a number of ways. For example, the following can occur when you exercise too much or too hard:
- Your body can enter a catabolic state, in which your tissues break down
- Excess cortisol (a stress hormone) can be released, which not only contributes to catabolism but also to chronic disease
- You can develop microscopic tears in your muscle fibers (which may fail to heal if you continue over-exercising), and increased risk for injuries
- Your immune system may be weakened
- You may develop insomnia, especially if your workout is in the afternoon or evening
However, the most serious risk involves damaging your heart—or worse yet,sudden cardiac death—which will be the focus of this article.
Are You Running the Risk of Sudden Death?
You’ve undoubtedly been stunned by the occasional news of an elite athlete suddenly dropping dead. These accounts are not as rare as you would hope, and science is finally shining some light on the cause. Marathon runners and triathletes have traditionally been seen as the perfect picture of fitness, the envy of “hobbyists” and professional athletes alike. Running a marathon is on many-a-Bucket-List.
But are the physical demands of this sort of training actually healthy or even safe? The latest research suggests not. High-endurance training puts extraordinary stress on your heart. Although stressing a muscle usually makes it stronger, extremely high stress can have the opposite effect—and your heart muscle is no exception.
Long-distance running leads to high levels of oxidative stress, inflammation, and damage to your heart tissues, producing acute physiological responses that can trigger a cardiac event.
The risk appears to be highest if you’re a middle-aged man, due to gender differences and changes that typically accompany aging. Men are two to three times more likely to experience a sudden cardiac arrest, the exercise issue aside. One 1984 NEJM study found that you are seven times more likely to have a heart incident while exercising than at rest. So, let’s take a look at the flurry of studies emerging over the past few years about exercise-related heart damage.
Eight Scientific Studies That May Stop You in Your Tracks
- According to a study presented at the Canadian Cardiovascular Congress 2010 in Montreal, regular exercise reduces cardiovascular risk by a factor of two or three, but the extended vigorous exercise performed during a marathon raises your cardiac risk seven-fold!
- In a 2011 study published in the Journal of Applied Physiology, researchers recruited a group of extremely fit older men, all members of the 100 Marathon club (having completed a minimum of 100 marathons). Half of the men showed heart muscle scarring as a result of their endurance running—specifically, the half who had trained the longest and hardest. If running marathons provided cardiovascular benefit, this group would have had the healthiest hearts!
- A 2011 rat study published in the journal Circulation 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.”
- A 2012 study in the European Heart Journal found that long-term endurance athletes suffer from diminished function of the right ventricle of the heart and increased cardiac enzymes (markers for heart injury) after endurance racing, which may activate platelet formation and clotting. Twelve percent of the athletes had detectable scar tissue on their heart muscle one week post-race.
- A 2010 study presented by the American College of Cardiology showed that endurance runners have more calcified plaque in their arteries (which also increases stroke and dementia risk) than those who are not endurance athletes.
- A 2011 German study revealed a very high incidence of carotid and peripheral atherosclerosis among male marathon runners.
- A 2006 study screened 60 non-elite participants of the 2004 and 2005 Boston Marathons, using echocardiography and serum biomarkers. Researchers 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.
Sustained Elevated Cardiac Output Can ‘Tear Apart’ Your Heart Tissue
