http://www.sciencedaily.com/releases/2009/04/090415113330.htmScienceDaily (Apr. 18, 2009) — Sleep is such an essential part of human existence that we spend about a third of our lives doing it -- some more successfully than others. Sleep disorders afflict some 50-70 million people in the United States and are a major cause of disease and injury. People who suffer from disturbed sleep have an increased risk of heart attack, stroke, hypertension, obesity, depression, and accidents. Nearly a fifth of all serious car crashes, in fact, are linked to sleeplessness. (...)
Now, a group of scientists in Israel and Germany has discovered a simple new way to monitor sleep and potentially diagnose sleep disorders just by recording someone's heart rate. Their method relies on using a mathematical technique to analyze these recordings and tease out information related to the synchronization between heartbeat and breathing, which might be a measure of fitness of the cardio-respiratory system. (...)