In the fourth century B.C., a man named Androsthenes, who was a scribe to Alexander the Great, traveled with Alexander and his army to India. While on that march, Androsthenes noted that the leaves of certain trees opened during the day and closed at night, and he made notes about that in his records of the military campaign. Of course, he didn’t know why that happened, but science has since explained the mechanisms involved. In some plants, the movements are brought about by fluids moving in special joints called pulvini. In other plants, such as tomatoes and cotton, movement is caused by alternating growth of the upper and lower part of the leaves.

            Scientists call these changes that repeat in 24-hour cycles “circadian rhythms.” Researchers have concluded that such cycles are not limited to plants. In fact, in 1999, a team of Massachusetts General Hospital scientists discovered that the same genetic machinery that controls the inner movements of the plant clock may drive the basic rhythms of the body -- the rise and fall of body temperature, blood pressure, hormones and the sleep-wake cycle. One possible benefit of such research may be help for people who have trouble sleeping.1

            But research aside, most of us already have a pretty good idea that our energy does cycle throughout each day. When we talk about being a “morning person” or a “night person,” we are referring to our own circadian rhythms, times when our energy peaks or plummets.

            And morning and night are not the only energy hills and valleys in a 24-hour period. Lot

...approximately 1,466 words remaining. You are not logged in. Please see options at the top of this page to view complete sermon.