This ongoing project will examine the interaction of sleep, sleep states, and the placement of sleep in the 24-hour cycle, with age. We will further examine the impact of this interaction on cardio-respiratory functions. With the shift from one state of alertness to another, there is a shift in the balance of the autonomic nervous system (ANS), which modulates the activity of many internal organs. A dysfunction of either the ANS or a specific organ may increase physical decline and morbidity, and may possibly increase the risk of early mortality. The aging process appears to disrupt ANS modulation, and the resulting dysfunctions may be more apparent and more detrimental during sleep or during a specific sleep state, than during wakefulness. We shall pursue the two lines of investigation in aging subjects. A) We shall perform an evaluation, in elderly subjects who present ventricular ectopy. This investigation will involve the roles of sleep states, sleep stages, inactivity, the supine position, and the placement of sleep in the 24-hour cycle on the occurrence of the ectopies. B) Sleep and sleep states are known to modify breathing and upper airway patency. We shall investigate whether sleep and sleep increase cardiovascular risk in aging subjects through their impact on breathing and airway patency. Several protocols will be performed to determine what variable may pose the greatest risk and whether we should pay more attention to sleep states in investigating elderly subjects. The study will pinpoint morbidity risks, allowing us to progressively develop preventative strategies against cardiovascular events. Thus our sleep related evaluation will provide information that may contribute to methods of reducing personal, familial and social costs brought about by cardiovascular problems.