I lift weights but don't do cardio. Is this heart healthy?

If you have time for only 3 workouts a week, keep doing what you're doing. When researchers at the University of Alabama compared the effects of a healthy diet and cardio with a healthy diet and strength training, they found that the latter strategy was far superior for boosting heart health. Why? Strength training fires up your metabolism for 38 full hours after you workout, resulting in greater fat loss. The closer you come to your ideal weight, the healthier your heart becomes. It's that simple. If you have time for one more weekly workout, however make it cardio. A recent study in the journal of Clinical Science found that aerobic exercise trains your cardiovascular system to transport oxygen more efficiently, another cornerstone of heart health, in an ideal world, you'd do three total-body strength sessions a week, as well as one or two 30 minute cardio sessions in the form of intervals.