Coffee has a stimulating effect on the heart and nerves, but it is best not to drink it if you have a heart condition. Coffee contains caffeine and other substances in the human body can promote sympathetic excitation, enhance metabolism, can make breathing faster, heart rate increase, blood flow faster, blood vessel expansion and other effects, a small amount of coffee on the people have a refreshing, relieve or eliminate fatigue effect, moderate amount of coffee on the body also has to improve the metabolic effect. The American Society for the Prevention of Heart Disease authoritatively recommended and published review articles for the top ten cardiovascular risk factors, pointing out that moderate coffee can reduce the risk of cardiovascular disease. People with underlying heart disease, an article in the Journal of Clinical Electrophysiology reported that the study found that long-term excessive intake of caffeine will cause excessive sympathetic excitation, lowering the threshold of cardiac excitation, easily induced supraventricular tachycardia, ventricular tachycardia and other tachyarrhythmias, which in turn triggered the risk of sudden death, so for people with underlying cardiac disease, should be prohibited from excessive intake of coffee. If you feel uncomfortable after drinking coffee or suffer from heart disease, it is recommended that you seek medical attention and follow your doctor’s advice on coffee consumption.