Experiencing an increased heart rate while lying down can occur due to several reasons, such as anxiety, changes in blood flow, or even caffeine intake. It’s important to identify any other symptoms you might have and consider your recent activities or stress levels. To help manage this, try practicing relaxation techniques like deep breathing or gradual changes in position when lying down. However, if these feelings persist or worsen, I recommend reaching out to a cardiologist. They can perform a thorough evaluation and provide tailored advice to ensure your well-being is prioritized.