Sleep pattern and daytime differences in the electromyographic activity and peripheral temperature.

For a long time, it has been said that most individuals sleep an average of 8 h. However, there are subjects that usually sleep less than 6 h (the ones placed under the label of short sleep pattern, SSP) and subjects that sleep more than 8 h (those classified by the long sleep pattern, LSP). Starting from this division, several studies have been carried out in order to establish possible differences in terms of psychological and physiological variables. This study is aimed at assessing the differences that might occur in electromyographic activity and temperature in long, medium and short sleep pattern subjects at two moments in the day. From a 300-subject sample, 17 long sleep pattern, nine medium sleep pattern and eight short sleep pattern subjects were selected. The physiological variables were assessed during a constant stimulation task in the morning (between 09.00 and 10.00 h) and in the evening (between 19.00 and 20.00 h). The inter-group analysis showed that the long sleep pattern and the short sleep pattern subjects differed in terms of electromyographic activity in the morning. This same analysis indicated that only long sleep pattern subjects showed changes in electromyographic activity over two measurements taken in the same day. The results point out that long sleep pattern subjects show more sensitivity towards changes, and that sensitivity is expressed in a different manner, depending on the time of the day.