Rapid Heart Rate and High Blood Pressure
You may experience an accelerated heart rate when you have higher than normal levels of serotonin in your body. Your heart starts to beat faster because it is working more. This has the consequence of increasing the speed at which blood flows through your blood vessels, resulting in elevated blood pressure. This increase in blood pressure often clears once serotonin levels are back within their normal levels. High blood pressure induced by serotonin can have dire consequences, particularly in people with existing chronic high blood pressure. [3]
In more severe cases of serotonin syndrome, you may develop irregular heartbeats or tachycardia when the heart begins to beat abnormally fast. [4] This often makes you feel like your heart has skipped a beat or added an extra beat. According to Mayo Clinic, if you develop irregular heartbeats, it could be a sign that the serotonin syndrome has become potentially life-threatening. [5]