Build Up to High-Intensity Training

In light of increased participation in high-intensity training and increased rates of heart attack and sudden cardiac death among male marathon participants, the American Heart Association has issued a scientific statement to outline the benefits and risks of vigorous exercise programs. After reviewing more than 300 studies, authors for the AHA noted that risk of heart attack and sudden cardiac death is up to 50% lower in physically active people, such as regular walkers; however, intense exercise training can present its own potential risks, particularly to new exercisers or those with underlying or undiagnosed cardiovascular conditions like heart rhythm abnormalities or a prior heart attack.

The AHA has these recommendations for those who are starting a physical activity program:

• Warm up by doing the planned activity at a slower pace to let heart rate rise gradually.
• Walk on a level surface for 6–8 weeks, progressing to hills, jogging or more vigorous activities as long as you have no symptoms such as shortness of breath, lightheadedness, chest pain or chest pressure.
• Increase exercise time incrementally, from 5 to 10 minutes at first, and gradually build up to longer times.
• Lower exercise intensity when new or different environmental conditions—such as high humidity or high altitude—may strain the heart.
• Cool down after exercise to let heart rate return to normal.
• Stop and seek medical evaluation if you experience any heart-related symptoms such as lightheadedness, shortness of breath, or chest pain or pressure.

The new statement, “Exercise-related acute cardiovascular events and potential deleterious adaptations following long-term exercise training: Placing the risks into perspective—An update from the American Heart Association,” is available in Circulation (2020; 141, e705–36).

See also: High-Volume, High-Intensity Exercise Is Safe for Men