One session is unlikely to induce a heart attack in an individual with a healthy heart. But it can act as a trigger for people who have underlying coronary artery disease. The sudden increase in blood pressure and heart rate may destabilise plaque in your arteries or overwork a heart that’s already struggling. For a person with undiagnosed heart conditions, the intense, repeated stress could potentially start a cardiac event. This makes it a serious risk for at-risk groups.