Live longer by strength training: The benefits of lifting weights include everything from bone health to brain function, body composition, mobility, and longevity.
The same cannot be said for endurance training. Rather, high volume endurance exercise increases risk of heart dysfunction, and low volume training compromises body composition by reducing muscle mass and having no effect on fat loss. Let’s look at new research into the effects of different exercise modes on the body.
A review from the Mayo Clinic showed that a high volume of endurance exercise from running, rowing, swimming, or cycling increases the thickness of the left ventricle, and that this remodeling leads to reduction in right ventricular function. Recent evidence shows these changes aren’t benign and that the dimensions of the heart don’t return to baseline, even a few years after discontinuing training.
The effects of impaired cardiac function include the following:
• Evidence of myocardial injury, In a group of endurance athletes, myocardial scarring was found in 12.5 percent, and the scarring was more common in those who had been training for the longest period of time.
• Increased risk of atrial fibrillation and arrhythmia due to scarring, fibrosis, and increased aortic stiffness. Blood pressure dysfunction and aortic stiffness were much higher in one study of marathoners than controls.
• Greater evidence of calcified plaque buildup in the coronary arteries from endurance exercise, putting athletes at greater risk for atherosclerosis.
All this cardiovascular misery is caused by the long training periods in which athletes experience sustained, intense stress with high heart rate, blood pressure, and cardiac output. Endurance exercise also produces a large amount of oxidative stress that overwhelms the body’s buffering capacity and can cause inflammation.
For example, a recent study compared the effect of training load in triathletes on oxidative stress biomarker. Researchers found that the athletes who trained the most (nearly 18 hours a week) had much greater oxidative stress that caused endothelial damage than athletes who trained less than 14 hours a week. The study authors conclude that “the beneficial effect of aerobic exercise are eliminated when the training is performed at the greater workload.”
Of course, 14 hours of endurance exercise is still a very high volume that may compromise heart function and can lead to bone loss and lower muscle mass. Repeatedly studies have shown that endurance exercise, particularly swimming and cycling that are not weight bearing activities, lead to bone loss in the long term. In fact, recent studies have found osteopenia or very low bone mass in elite cyclists. In addition, in the absence of weight training, long-term endurance training can lead to loss of muscle mass, compromising performance and health.
For the recreational trainee, aerobic exercise IS better for you than being sedentary. The point that a lot of people are still confused about is that weight training and higher intensity, shorter duration exercise is better than aerobic exercise for health and longevity. Weight training improves heart function to the same degree as aerobic exercise, builds muscle and bone, aids in hormonal regulation, decreases chronic inflammation, and supports body composition—all key factors in living a long life.
The take away is twofold: Weight training is essential for all populations for better health and longevity. If you want to do endurance training, be aware that higher volume training can compromise cardiovascular health.
O’Keefe, J., et al. Potential Adverse Cardiovascular Effects from Excessive Endurance Exercise. Mayo Clinic Proceedings. June 2012. 87(6), 587-595.
Conti, V., et al. Aerobic Training Workload Affects Human Endothelial Cells Redox Homeostasis. Medicine and Science in Sports and Exercise. 2012. Published Ahead of Print.