Sleep apnea is a potentially serious, yet common, sleep disorder that can affect people of all ages, lifestyles, and health or fitness levels. It disrupts the quality of your sleep, leaving you with little energy to enjoy, or even carry out, your regular activities. It is characterized by repeated episodes of shallow or paused breathing during sleep, and since these symptoms occur when we are asleep, sleep apnea and sleep disordered breathing are often undiagnosed.