Why Are The Prayers Constantly Speaking of "When we lie down and when we rise up?" - A Practical Guide

If you were a literary critic analyzing the evening prayers, you would have to note how often the trope of going to bed and waking up is repeated:  Ahavat Olam before Shema, VeAhavta and VeHaya Im-Shmo'a after Shema, Hashkiveinu, and then Barukh Adonai  Bayom 'VaLayla on Weekdays or the Shabbat Psalm on Friday night.  Wow:  for a twelve minute service, you've prayed about going to sleep and waking up five times!) What is this all about?  And why is the most commonly studied volume of Talmud, Berakhot ("Blessings"), concerned greatly about the timing of nighttime and morning prayers as well?  In this podcast, I connect all of these with reflections about the psycho-physiological aspects of falling asleep and waking up, including theories about the function of prayer and a recent study on when one should be waking up.  I conclude with a very practical exercise for improving one's spiritual and physical health.