Some research has shown that dark chocolate may play a role in regulating stress hormones. What’s more, cocoa contains immune-boosting antioxidants that likely play a role in supporting cardiovascular health. According to Health Magazine, the cocoa in dark chocolate can trigger a relaxation effect in the walls of your blood vessels, which lowers blood pressure and improves circulation. Plus, new research shows that this sweet treat may even be able to provide a mid-day energy boost.