Central sleep apnea (CSA) is a condition where a sufferer will stop breathing temporarily while sleeping. This sleep disorder can occur several times during a single sleep period, which can be dangerous. If you stop breathing, your blood-oxygen levels can get dangerously low, and potentially result in hypoxemia, shortness of breath, coughing, wheezing, rapid heart rate, and confusion.
The most common symptom of CSA is frequent starts and stops of breathing during sleep, which can result in regular nighttime awakening and insomnia. For some people, breathing gets very shallow instead of actual breath pauses. Thus, a CSA sufferer can feel very sleepy during the day and have trouble focusing on tasks. Headaches when waking up are another possible symptom.