What can be done when a teen stays in bed well into the morning hours and has no energy to go to school? This is a common problem which adolescents should not be blamed for or made feel guilty about. Their brain is undergoing an upheaval.
The sleep rhythm of adolescents is being shifted by biological, psychological and social factors. Hanging out with friends, spending time on social media and playing games are rewarding activities, but they also postpone the onset of the secretion of melatonin, a hormone that helps the person fall asleep.
The circadian rhythm, which regulates sleep rhythm, and the homeostatic rhythm, which regulates sleep pressure, are often out of step with each other, especially in young people. They simply do not feel sleepy in the evening.
The adolescent brain undergoes a lot of changes connected to sleep. According to Liisa Kuula, a postdoctoral researcher in psychology at the University of Helsinki, changes in the brain and sleep take place by turns.
Kuula studies the links of sleep and stress with health in the Sleep Helsinki research group.
“Changes in the white and grey matter of the brain, related to brain development in adolescents, have a clear connection to changes that take place in the architecture and structure of deep sleep,” Kuula says.
Sleep, sleep, sleep
Poor sleep impairs our ability to learn and memorise things, as well as our brains' executive function and self-regulation. The adolescent brain in particular needs sufficient sleep in order to develop and function properly. This includes a good amount of all stages of sleep. However, two stages are especially important: deep sleep, also known as slow-wave sleep, and rapid eye movement or REM sleep.
“Sleep is synchronised according to the individual circadian rhythm, something that is quite difficult for people to actively regulate.”
Our internal clocks tick away, controlled by our genes, surroundings and personal sleep histories.
“A regular circadian rhythm is important for going through all of the sleep stages. An irregular one results in recovery sleep, a kind of ‘interest’ on the lack of sleep, which does not represent the best possible sleep architecture,” Kuula notes.
The brain is cleaned up during sleep
News about the health effects of sleep have emphasised the significance of deep sleep in particular. However, Kuula points out that light sleep also matters.
“All stages of sleep have to be timed correctly for sleep to properly fulfil its duty. Slow-wave sleep is important for growth and physical recovery, while REM sleep supports the regulation of emotions and the release of bottled emotions, such as stress,” Kuula explains.
When the REM stage is too short or fragmented, it can show, for example, as irritability and anxiety. A central factor associated with recovery and wellbeing is the glymphatic system, which operates while we sleep. It cleans the brain from waste products that hinder its function.
Anxiety keeps you awake
Prolonged sleep deprivation has many detrimental effects. The more it accumulates, the harder it becomes to concentrate, learn and remember things.
And when managing everyday life becomes difficult, we get increasingly anxious and stressed.
When someone is anxious, their brain requires sleep and recovery perhaps even more than usual, but anxiety prevents them from sleeping. Kuula points out that at its worst, such a cycle can knock a person off their path in studies, education and professional life.
Problems caused by insufficient sleep do not apply only to young people. Sleep is associated with mental and physical wellbeing in people of all ages. Lack of sleep quickly generates symptoms of anxiety and depression.
Insomnia is also associated with metabolism. Prolonged lack of sleep can lead to a continuum of problems ending in, for example, a cardiovascular disease.
Long-term chronic sleep deprivation increases the risk of developing Alzheimer’s disease and potentially other degenerative brain diseases and neurodegenerative diseases.
Breaking the cycle
In the Sleep Helsinki project, researchers are looking for different ways to help adolescents suffering from a delayed circadian rhythm.
“Skype discussions with a sleep coach have been one of the most effective ways of helping. The coach evaluates why the adolescent does not want to go to sleep in the evening,” Kuula says.
The coach will guide the individual to identify solutions appropriate to their circumstances.
“Sleep coaching carried out with the help of a powerful bright light lamp has gone a long way to correcting the circadian rhythm of adolescents,” Kuula says.
According to an old proverb, sleeping is like putting money in the bank.
Bad days, bad dreams
According to Postdoctoral Researcher Nils Sandman from the University of Turku, all psychological strain decreases the quality of sleep and increases the number of nightmares.
In his doctoral thesis in psychology, Sandman studied the prevalence of nightmares as well as related risk factors and consequences.
“Under a certain amount of strain, most people see nightmare-like dreams. The degree of strain needed to trigger them varies between individuals.”
Increasing nightmares may indicate strain experienced during wakefulness.
“Suddenly seeing nightmares when you don’t normally see any is most likely a sign of increased mental strain.”
Can nightmares also reduce stress and mental pressure experienced during waking hours in certain cases?
“According to some theories, a certain number of nightmares can be necessary for mental health. Others propose that learning that is useful also when awake can take place in dreams.”
At the same time, there are sleep specialists who consider dreams and nightmares a by-product of other brain activity without a particular purpose.
“What the evidence is clear about is the fact that severe nightmares recurring several times per week are associated with depression and sleep problems. This should be addressed,” Sandman says.
The article has been published in Finnish in the 10/2019 issue of Yliopisto magazine.