Pre-workout supplements may be beneficial for improving your workout performance, but they can also be potentially dangerous for your heart health. Some ingredients in pre-workout supplements can increase heart rate and blood pressure and may cause arrhythmias or other heart problems. It is important to talk to your doctor before taking any pre-workout supplement to make sure it is safe for you. Additionally, always read labels carefully and follow the recommended dosage instructions to avoid any potential side effects or health risks.