Olivia Newton John once told us in very fashionable legwarmers, "Let's get physical!" According to Haley, aerobic exercise is the best activity to get your heart pumping, but that doesn't mean you're required to log six miles on a treadmill every day. "The key is to find something that not only is challenging but fun at the same time," she says. "When doing cardio (like swimming, biking, dancing), ask yourself if it's becoming a little more difficult to breath. If so, your heart is working harder than normal which means you're strengthening it." This is why interval training (short bursts of speed followed by a recovery jogging period) is a great way to work out and get the blood circulating to your heart.
NEXT: Quick exercises to get your heart in shape in just five minutes flat.