Speaker Name(s): Michael J. Sole, M.D., F.R.C.P.(C), F.A.C.C., F.A.H.A., F.C.A.H.S. Description: There is a relationship between the day/night cycle and the occurrence of various medical conditions. For example, heart attacks tend to occur between 6am and 10am. However, there are no actual cause-and-effect data for any specific disease. I will show that many genes are controlled by internal cellular clocks and that gene expression varies according to the day/night cycle. My laboratory was the first to demonstrate that harmony between internal and external day/night rhythms is essential for healthy organ growth and repair and that discord (e.g. shift work, chronic sleep disruption) may cause diseases such as heart attack, heart failure, and kidney damage.