The first study, carried out by Lufi, Tzischinsky & Hadar in a public school in Israel, showed that delaying the school start time resulted in students sleeping about 55 minutes longer per night than a control group kept on the usual early schedule. This is an important finding in its own right as it confirms what earlier studies have indicated - when school starts later students actually use the time for sleeping and are not spending another hour on the computer, watching TV, socializing or doing home work. Two classes of students were assigned randomly to either the experimental group with an 8:30 AM start time or the control group with the standard 7:30 AM start time. Both boys and girls participated and the average age was 13.78 years. A significant aspect of the study was the cooperation of the transportation system and parents in accommodating the new schedule for the experimental group. The students in the experimental group showed significantly better performance on tests of attention and concentration. The tests used indicated that the students in the experimental group had better attention, were less impulsive and performed better. It was not clear whether the improvement was due to sleeping more or just being able to sleep later. This study strongly suggests that making a single change, a one hour later start time, could significantly improve cognitive functioning among middle school students.
In a previous post I discussed some of the benefits of having later school start times for junior high and high school students. Studies conducted in both public and private school systems in the USA have shown that even one more hour of sleep per night results in improved mood, attention and learning for students. Research is beginning to explain why sleep is so important for effective learning. Two studies, including one conducted outside the USA, support and extend earlier findings.