For most people, the benefits of aerobic exercise far outweigh the risks.
But in a new scientific statement, researchers found that extreme endurance exercise — such as participation in marathons and triathlons for people who aren’t accustomed to high-intensity exercise — can raise the risk of sudden cardiac arrest, atrial fibrillation (a heart rhythm disorder) or heart attacks.
They suggest that slow, steady increase in exercise intensity is best for heart health.
The research was conducted by a team at Oakland University and elsewhere.
Aerobic exercises are activities in which the large muscles move in a rhythmic manner for a sustained time.
They can be done at low intensity or high intensity and include walking, brisk walking, running, bicycling, swimming and many others.
The team says there is no question that moderate to vigorous physical activity is beneficial to overall heart 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, people with known or undiagnosed heart disease.
After reviewing more than 300 scientific studies, the team found that, for the vast majority of people, the benefits of exercise and improving physical fitness outweigh the risks.
Physically active people, such as regular walkers, have up to a 50% lower risk of heart attack and sudden cardiac death. However, the committee also identified potential risks with intense exercise training.
The writing group also reviewed a small study that concluded the risk of sudden cardiac death or heart attack is low among people participating in high-intensity exercises such as marathons and triathlons.
However, over time, the risk of heart attack or sudden cardiac death among male marathon participants has risen.
This suggests that these events are attracting higher risk participants. For women, who comprised only 15% of the study population, the occurrence of sudden cardiac death was 3.5-fold less than in men.
Among participants in triathlons almost 40% of cardiac events occurred in first-time participants, indicating that inadequate training or underlying heart problems may be involved.
For people who want to become more active, the team suggests that most people can start a light program of exercise and build up slowly to a moderate to vigorous exercise regimen without seeing a physician first unless they have physical symptoms such as chest pain, chest pressure or severe shortness of breath while exercising.
In addition, people with known heart disease (such as a previous heart attack, bypass surgery or angioplasty) should get their doctor’s approval prior to starting an exercise program.
One author of the study is Barry A. Franklin, Ph.D., the chair of the writing committee for the new Scientific Statement.
The study is published in Circulation.
Copyright © 2021 Knowridge Science Report. All rights reserved.
