Both sleep deprivation and sleep apnea have been linked to a higher risk of heart disease. Over time, inadequate or poor quality sleep can increase the risk of heart disease. Short–term sleep deprivation is linked with high cholesterol, high triglycerides and high blood pressure. Sleep apnea makes people temporarily stop breathing many times during the night. Up to 83% of people with heart disease also have sleep apnea. In sleep apnea, oxygen levels dip and the brain sends an urgent "Breathe now!" signal. That signal briefly wakes the sleeper and makes him or her gasp for air. That signal also jolts the same stress hormone and nerve pathways that are stimulated when you are angry or frightened. As a result, the heart beats faster and blood pressure rises — along with other things that can threaten heart health such as inflammation and an increase in blood clotting ability. (Source: Harvard)