Sleep is important for us in many ways. We suffer mentally and physically when we do not get enough. It is the time our body repairs itself, releasing hormones for the benefit of damaged cells. Other hormones influence how our bodies use energy from food.

Generally, we know that getting enough sleep is helpful. But that does not mean more sleep is better. Sleeping more than 11 hours can be a sign of poor mental health. For students, it can be linked to poor grades.

Andrew Fuligni, a psychologist at the University of California, Los Angeles, wanted to find out what amount of sleep was perfect for mental health and learning. He and his team got to work with 421 Mexican-American kids in ninth and tenth grades to find out.

They found that students with the best GPAs got 7.5 hours of sleep each night. However, students felt best when they averaged 8.75 hours of sleep per night. They were less riddled by anxiety and stress and instead felt more confident.

They also found that having much more or less sleep resulted in poorer mental health.

kitten-2874486_1920 Cats can sleep up to 20 hours a day. Photo: Monicore from Pixabay

“High-achieving kids make sacrifices in sleep,” Fuligni says. To get those high GPAs, many skimp on sleep. But, he adds, “There’s not necessarily a huge payoff.” That lost hour of sleep may be tied to a slight increase in GPA. But, he notes, it can come at a cost to mental health.

Many of us try to repay the sleep debt we incurred during the week and usually in one of two ways: sleeping in on weekends or napping. Sometimes even both.

The team found that teens that slept in suffered poorer mental health than teens that regularly logged consistent hours throughout the week.

Getting different amounts of sleep everyday shifts our body's natural 24-hour clock known as the circadian rhythm. “Psychological well-being is driven by circadian rhythm,” he explains. Fuligni likens waking up at 6:00 a.m. during the school week and then noon on the weekends to flying a return trip from California to New York weekly. “The body is constantly jet-lagged.”

As for nighttime sleep and napping, Karen Jakubowski, a psychologist at the University of Pittsburgh in Pennsylvania, studied data from 236 high school students to look for a link between the two.

Those that got less than 6.5 hours per night were more likely to take a nap the next day, and 89 percent of teens napped at least once a week, usually when there was school. These naps are usually between 60 to 80 minutes.

Though seemingly harmless, the team found that teens would then go to bed later and sleep less that night, making them even more tired the following day.

“There seems to be a cycle of poor sleep at night and napping,” she says.

Not to say that napping is bad: quick 30-minute cat naps have been shown to boost memory and attention in adults. Plus, it is better than reaching for a cup of coffee, which could be counterproductive as it can decrease memory performance.

At the end of the day, what scientists are saying is that people should try to improve nighttime sleep. “Put your phone away and avoid blue light from computers,” Jakubowski says. Instead, do relaxing activities such as reading which help the brain and body prepare for sleep. You would not want your phone near you either as notifications can disrupt your sleep.

The number one thing Fuligni advises: stick to a steady sleep schedule. “The body is very attuned to habits,” he says. By sleeping at the same time every night, the body will come to sleep faster and better. In the long run, our body and mind will be rewarded.