On an average we sleep for ca. 8 h per day and stay awake for 16 h. However, the period length of these rhythms, as for instance between successive maxima is not exactly 24 h any more as under normal day-night conditions. Sleep-wake periods of a baby in the first 26 weeks of life, according to Kleitmann and Engelmann, 1953. From the 16th week onward the child is synchronized to the 24 hour day.
Activity is now mainly restricted to the day, sleep to the night, the parents relax.
We propose to conduct a test which will show to which phase type you belong. Besides you can record your own body temperature automatically and determine temperature maxima and minima in each cycle. We could expect that the 'morning' type of persons experience temperature minima to occur earlier in the night than do 'evening' type of persons.