Effects of aging and female reproductive hormones on responses to chronic sleep loss.

Chronic sleep loss is common in industrialized countries as a result of a rising demand for people to work longer hours and at non-traditional times. Chronic sleep loss has been associated with a higher risk of heart disease, obesity and diabetes. Sleep loss has a vast impact on the economy due to missed work, increased risk of accidents and medical costs. Women report more sleep problems than men and aging, in both sexes, is linked with decreased sleep quality and quantity. The efficiency of recovery sleep after sleep loss influences how well people compensate for and adapt to chronic sleep loss, but little is known about how aging and female sex hormones affect recovery of lost sleep. Animal models of sleep loss have been created to help us understand the effects of sleep loss. Most of these models prevent sleep for a continuous period of time instead of limiting sleep over many days, which is the most common type of sleep loss that is seen in humans. We will study how female sex hormones and age affect sleep loss recovery in a rat model. Our model will reduce the daily amount of sleep over four days and will take into account the natural sleep pattern of rats. To do this we will prevent sleep for 3 hours, followed by a 1 hour sleep window, followed by 3 hours without sleep, etc. This schedule will decrease their sleep amount by ~50% and will match the rat's normal cat-nap sleep pattern. The information we collect will be useful for the development of strategies to help improve quality of sleep and, thus, quality of life for the elderly and for women.