If left untreated the frequent reductions in oxygen levels, caused by Sleep Apnoea, cause a significant physiological stress to the body. This is because the brain detects the lowered oxygen levels and causes the sufferer to have regular awakenings or “micro-arousals” so that the throat muscles can open up the airway. The sufferer may not be aware of being awake during a micro-arousal but he/she does not get sufficient restful sleep with frequent episodes. As a result people with OSA are excessively tired and sleepy during the day. They may also have problems with concentration and mood changes. People with significant Sleep Apnoea are at higher risk of cardiac disease, strokes, diabetes, pulmonary disease, hypertension and early death. These risks are greater in severe Sleep Apnoea.