A heartbeat that feels like a heartbeat when there is a sound, and possibly shortness of breath, chest tightness, and shortness of breath are considered to be hypervigilance, related to nervousness, worry, fear, or feeling threatened. It can also be seen in physical illnesses, such as problems with heart function, such as coronary heart disease, and possibly hyperthyroidism, menopause, and hypoglycemia. Also taking medications may cause hypervigilance, such as hormonal drugs, and people who drink alcohol are prone to it. Also patients who work under tension and stress may also have increased alertness.