It is important to note that extreme endurance exercise, such as marathons and triathlons, can raise the risk of sudden cardiac arrest, atrial fibrillation (a heart rhythm disorder) or heart attacks for people who are not accustomed to high-intensity exercise
The new study titled Exercise-Related Acute Cardiovascular Events and Potential Deleterious Adaptations Following Long-Term Exercise Training: Placing the Risks Into Perspective identifies aerobic exercise as activities in which the large muscles move rhythmically for a sustained time. They can be done at a low intensity or high intensity and include walking, brisk walking, running, bicycling, swimming, and many others.
Exercise is Medicine
“Exercise is medicine, and there is no question that moderate to vigorous physical activity is beneficial to overall cardiovascular health. However, like medicine, it is possible to underdose and overdose on exercise – more is not always better and can lead to cardiac events, particularly when performed by inactive, unfit, individuals with known or undiagnosed heart disease,” said Barry A. Franklin, Ph.D., chair of the writing committee for the study.
“More people are running marathons, participating in triathlons and doing high-intensity interval training. The purpose of this statement is to put the benefits and risks of these vigorous exercise programs in perspective,” Franklin added.
Researchers reviewed more than 300 scientific studies and found that the vast majority of people benefited from exercise. The physically active participants such as regular walkers had up to a 50% lower risk of heart attack and sudden cardiac death.
However, the committee also identified potential risks with intense exercise training. It was shown that the risk of sudden heart attack is low among those participating in high-intensity exercise, however, over time, the risk for a heart event including sudden cardiac death among male marathon participants shows a rise.
This suggests that these events attract higher-risk participants (those who may have an underlying or undiagnosed cardiovascular condition such as heart rhythm abnormalities or a prior heart attack). For women, who comprised only 15% of the study population, the occurrence of sudden cardiac death was 3.5-fold less than in men.
For those who want to ramp up their exercise routine, the Association suggests starting with a light program of exercise and build up slowly to a moderate to vigorous exercise regimen. “It is important to start exercising—but go slow, even if you were an athlete in high school,” said Franklin.
Be sure to see a physician if you experience any symptoms such as chest pain, chest pressure, or severe shortness of breath while exercising. For those who have heart disease, it is important to get a doctor’s approval prior to starting an exercise program.