University of São Paulo: Mental health and academic performance- Starting class an hour later can be beneficial for teens

Starting classes an hour later helped improve the academic performance and mood of teenagers, affecting traits such as tiredness, tension, anger and depression. This is what a study entitled Multiple positive outcomes of a later school starting time for adolescents shows , carried out with the participation of high school students from a private school in Palotina, Paraná.

“Good quality sleep is linked to a healthy mind, less depression and more willingness and ability to carry out everyday actions. We wanted to show that by delaying class time, students could sleep more and, therefore, be more prepared to learn”, tells the Jornal da USP Mario Pedrazzoli, a professor at USP’s School of Arts, Sciences and Humanities (EACH) and one of the article authors.

Determining sleep time

A total of 48 students from different grades of high school from a private school in Palotina participated in the study: 17 students were in the first year; 23 for the second and eight for the third. Parents and teachers attended a presentation about the study before the students were invited to participate in the research.

It took three weeks to assess the changes in the students: in the first, classes started at the normal time, at 7:30 am. On Monday, classes started at 8:30 am. And in the third week they went back to regular time. The organization of these three weeks was a differential of the research: in previous studies, the researchers took advantage of the fact that schools were going to change the schedule to assess the situation. “With that, we demonstrate that, when it goes back to the old time, everything gets worse again”, comments Pedrazzoli.

Sleep time was tracked by a method known as actigraphy. During the three weeks the participants wore an actigraph, a device that is shaped like a clock and measures sleep by movement, temperature and light exposure. In addition, information related to the emotional profile was evaluated by a scale with 65 items and a score from 0 to 5.


Bedtime, time in bed, sleepiness, total sleep duration and waking up time were some of the factors recorded by the actigraphy method – Photo: Provided by the researcher

The circadian cycle is responsible for regulating daily activities in a 24-hour period. It’s like a biological clock that sets the best time to eat or sleep. This cycle is controlled by the hypothalamus (a region of the brain that regulates body temperature, hunger, thirst and sexual behavior) , which, upon receiving information about the presence or absence of light captured by the retina, regulates the production of hormones.

In the case of sleep, at night, when there is less light, there is the production of melatonin, which stimulates sleep. Already in the morning, with more light, there is the production of cortisol, which makes us wake up.

During adolescence, the circadian cycle is affected, which explains the difficulty of people in this age group to wake up early. “It’s a characteristic of the development process, along with the body’s process of maturation that takes place in adolescence: as well as the growth spurt, there is a delay in the time of sleep onset”, says Pedrazzoli. The time of sleep, which usually starts around 8 pm or 9 pm, moves to 10 pm or 11 pm in adolescence.

“So, we can imagine that teenagers constantly sleep less than they need”, he points out. That’s why delaying the start of classes by an hour has positive consequences.

The researchers figured that the week the class would start at 8:30 am, bedtime would change. However, there was no significant change at this time. Thus, the teens slept longer in the second week: from about 7 hours to 7 hours and 35 minutes.

Pedrazzoli explains that, during sleep, the brain organizes information from each day, making emotional adjustments and processing memories. “So memories are processed and stored while we sleep, and it’s all about learning,” he says.

As for the mood of the adolescents, in the second week, they reported less tiredness, anger, tension, confusion and depression. They also reported having more energy. The TMD, which measures mood disturbance and is the sum of tiredness, anger, tension, confusion and depression minus the energy value, was also lower.

Understanding the benefits that longer sleep time brings to students is important to encourage the creation of actions to change school schedules. “We know that people have different circadian cycles, in the case of teenagers the sleep schedule is later compared to the general population. So, public policies are needed to take care of these schedules”, says Pedrazzoli.

California , in the United States, for example, delayed the start of classes in order to improve student performance. The law went into effect in July of this year and mandated that high schools must not start classes before 8:30 am. Meanwhile, in Brazil, where schools start classes around 7:30 am, there have not yet been any changes in timetable.

Pedrazzoli also comments on the discourse of the hypervaluation of work, which is often related to a feeling of pride and diminishes the importance of sleep. “Working while others are sleeping”, reproduces the teacher. “But sleep is not a waste of time, it is a gain of life; Sleep is a moment in life in which the brain prepares the brain and the body to live the next day with quality.”