As you get older, your arteries stiffen, reducing blood circulation, says Jonathan Drezner, MD, director of the UW Medicine Center for Sports Cardiology in Seattle who was not affiliated with the study.
Aerobic exercise can prevent that hardening, which helps you train longer and more intensely since more blood can reach your muscles, he explains. Cardio may have this effect because it dilates the blood vessels and causes your body to release beneficial hormones.
If cardio is a regular part of your routine, you're well protected—but if you only lift, you're not.
The bottom line:
The study definitely makes a case for running a marathon, but you can get the benefits from any activity that raises your heart rate. Drezner suggests working towards at least 75 minutes of intense cardio per week.
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Photography by Mohamed Sadek