Exhaustion is so common that we often explain it away. The children are up early, work is busy, or it must be "the change". Sometimes those explanations are right. But for some people, the real cause is a breathing problem during sleep that has never been identified.

Sleep is not one continuous state. Through the night your brain moves through a repeating pattern of stages, known as sleep architecture. Each cycle lasts roughly 90 minutes, and most adults complete four to six cycles a night.