Is lack of sleep contributing to your child’s stress?

Asked by Anonymous on our Parent Webinar series.

Sleep is your child’s greatest ally in ensuring that their stress levels don’t blow out to unhealthy levels. It is also one of the most overlooked or underappreciated components of stress management. In the US, the CDC (Centers for Disease Control and Prevention) found that only 22% of high school students get the recommended 8 or more hours of sleep per night, meaning the vast majority are chronically under-slept. Similarly, the Victorian Government has found that most teenagers in the State get between 6.5 and 7.5 hours of sleep a night, which is also deemed insufficient.  

The question is then: how many hours of sleep is your child getting? Research shows that teenagers need between 8-10 hours of sleep a night, and if your child is getting any less than this then lack of sleep may be contributing to your child’s excess stress. These 8-10 hours play a critical role in lowering stress levels in the following ways: 

• Lower cortisol levels: Cortisol is the main stress hormone. Your cortisol levels are at their lowest when you sleep, effectively resetting your cortisol and stress levels for the next day.  

  
  

• Strengthened prefrontal cortex: The prefrontal cortex is the part of the brain responsible for managing self-control, attention, focus, and emotions. Even one night of poor sleep has been shown to make the amygdala (the brain’s emotional alarm system) up to 60% more reactive to negative stimuli. At the same time, the prefrontal cortex becomes less active, weakening its ability to regulate those emotional responses. The result is a child who is more emotionally volatile, more responsive to stress, and significantly less able to focus. 

  
  

• Better REM sleep, meaning better control of raw emotions: Studies by the University of California, Berkeley show that REM sleep is responsible for helping people file away raw emotions, such as an argument your child might have had with their friends at school, or the disappointment of a poor mark. Insufficient sleep leads to less REM sleep and less filing of raw emotions. This means your child is more likely to carry the negative emotion into the next day, instantly increasing stress levels. 

Lack of sleep also impacts stress in a second way: lower concentration, attention and cognitive processing. As we’ve seen sleep is critical for re-setting the pre-frontal cortex, the part of the brain that is responsible for attention, impulse control, and decision making. Lower levels of attention lead to foggier thought and reduced memory retention, which makes study feel much harder than it actually is which in turn dials up stress levels further.  

Your child’s goal is to make sure they get 8-10 hours of sleep a night. Going to bed early isn’t going to get them cool points, but it is an easy way to help contain excessive stress. 

Your child can improve their sleep by:

• Not having their phone in their bedroom: The number one reason that teenagers don’t get enough sleep is because they have their phones with them in bed, and the lure of the phone keeps them scrolling until the early hours. Even worse, a high percentage of students will check their phones when they wake up at night, making it much harder to get back to sleep. As such, children should acknowledge that the phone is a temptation and keep it out of the room. 

  
  

• End study 90 minutes before going to bed: The CDC found that one of the most at-risk groups for low levels of sleep is Year 12 students because they were studying so much. Ideally, your child should try to complete all their study 90 minutes before going to sleep. This will allow their cortisol levels to start to drop sufficiently enough for them to be less wired. 90 minutes also provides your child with sufficient time for their melatonin levels to rise. Melatonin is the hormone that signals to the body that it’s time to sleep. Blue light, which is emitted from devices such as laptops, iPads, and phones, suppresses your melatonin levels, making it harder to go to sleep (another good reason your child shouldn’t have their phone in the room).   

  
  

• Don’t consume caffeine whilst studying in the evening: When your child has been at school all day, they’re tired, their attention is flagging, and they still need to smash out 2 hours of study, it’s understandable that they might be tempted to reach for enough caffeine to disqualify an Olympic athlete from competition. However, the problem is that caffeine has a half-life of 5 hours, which means 5 hours after that caffeine hit, 50% of that caffeine remains in their bloodstream. It can take up to 10-12 hours for all the caffeine to be removed from the bloodstream. So all of a sudden, a coffee or a Red Bull at 5pm leaves your child with 50% of the caffeine still in their blood at 10pm when they are probably thinking about bed.

  
  

• Keep sleep and wake times consistent — including on weekends: This is one of the most overlooked sleep habits, and one of the most impactful. The brain’s circadian rhythm operates like an internal clock, and inconsistency, such as  going to bed and waking at very different times across the week , disrupts that clock significantly, reducing sleep quality even when total hours are adequate. Many teenagers use weekends to “catch up” on sleep, but research shows this strategy doesn’t work well. Sleeping in by two or more hours on Saturday and Sunday effectively gives your teenager social jet lag, resetting their body clock and making Monday morning even harder to manage. A consistent wake-up time — even on weekends — is one of the most effective anchors for better sleep quality through the week.

  
  

• Use the 90-minute wind-down window productively: We’ve already recommended finishing study 90 minutes before bed and keeping screens off, but what should your child actually do in that window? The research points to a handful of activities that actively support sleep onset: reading a physical book (not a device), light stretching or gentle yoga, journalling to offload the mental load of the day, or a short mindfulness or breathing exercise. These activities lower cortisol, allow melatonin to rise naturally, and give the nervous system the signal that the day is genuinely over. The wind-down window is not dead time but rather when used well, it is some of the most valuable preparation your child can do for the next day.

  
  

The bottom line

Sleep is not a passive recovery state, it is an active neurological process that resets your child’s stress hormones, repairs their emotional regulation, and restores the cognitive capacity they need to learn and concentrate. No amount of studying, tutoring, or motivation will compensate for a brain that is running on insufficient sleep. The good news is that the habits above are not difficult to implement and the improvements they produce in mood, focus, and stress levels,  tend to show up within days. Start with one change, hold it for two weeks, and watch what happens.