HoustonTexans.com reported that Houston Texans DE Mario Williams underwent sleep apnea surgery last month. It is a minor procedure, and Texans OL Antoine Caldwell had the surgery over the offseason, as well. Sleep apnea is a sleep disorder characterized by stoppages of breathing during sleep. Each episode is called an apnea, and there can be two different types of apneas: (1) a minimum ten-second intervals between breaths or (2) a blood-oxygen desatruation of 3-4% or greater. Generally, the person who has the sleep disorder will be unaware of the disorder; rather, it is another who witnesses the person’s apnea episodes. It is expected that over 18 million people suffer from sleep apnea.