Yoga is just as helpful for lowering your chances of heart attack as aerobic exercise. Check out this study written by my friend and PhD candidate at Harvard School of Public Health, Paula Chu.
How is this achievable when yoga does not burn as many calories per minute as running? My theory is that it creates a closer mind-body awareness, which enables you to make healthier choices in all things - such as how you eat, sleep, and deal with stress.
Yoga also decreases inflammation in the body. Inflammation is the basis for so many diseases in our modern day life, including heart disease. This study by Pullen, et al, looked at high sensitivity CRP, which is a lab test that gauges the overall level of inflammation in your body. The higher your C-reactive protein, the higher your risk of heart attack. They found a significant decrease in CRP after doing yoga for just 8 weeks. There were only 19 people studied, but hey, you gotta start somewhere. And let's be honest - these studies will never be funded the way that big pharma can fund research to find the next blockbuster, profit-stacking new drug. But this doesn't mean that they aren't important.