Every cup reduces the stroke threat by 8% - and the risk of developing heart failure by 7%.
However, scientists believe the benefits plateau and previous studies suggest that a maximum of three cups a day can be beneficial. It is also not clear how long the benefits of each cup lasts. The latest research, presented at an American Heart Association conference in California, bolsters evidence that coffee benefits the circulatory system.
Scientists believe the antioxidant plant compounds in the drink - rather than caffeine - are responsible for the benefits.
The research by the University of Colorado School of Medicine used a computer model to calculate the benefit of each coffee, based on previous long-running health studies.