Why is it so hard to wake up for school?

Kate MacDonald
19 December 2017

Above: Image © OSTILL,iStockPhoto.com

Tell me if this sounds familiar: Your alarm goes off at 7:00 am. It’s a school day. It’s time to get out of bed and get ready to make that early morning bell. But in that moment, you feel as though there is no force on the planet that could make you open your eyes and surrender your comfortable position under the covers. Your mom comes into the room, already dressed for work. “You know,” she says, “you wouldn’t be so tired if you’d just gone to bed a little earlier.”

Is she right? Also, why isn’t she ever tired in the morning?

Most teens would agree that they’re much sleepier in the morning than their parents are. There’s a single molecule that’s largely responsible for this difference. And no, it’s not caffeine - it’s melatonin!

Melatonin is the hormone that regulates sleep in many animals. All humans produce it, but your adolescent body works a little differently than your parents’ bodies do. That difference is the reason why you feel so tired in the morning. Once you understand how melatonin works, you’ll see that there are things you can do to help yourself wake up on time.

The melatonin cycle demystified

Melatonin is produced mainly by the pineal gland, a small, pinecone-shaped mass located in the centre of your brain. Like many of the chemicals in your body, melatonin is produced in a 24-hour cycle regulated by circadian rhythms, or “internal body clocks”.

Light regulates melatonin production. When there is little or no light, melatonin production begins. When bright light hits the retina at the back of your eye, melatonin production stops.

Once your brain produces melatonin, it releases it into your blood. Melatonin then circulates throughout your body. This makes you feel drowsy and helps you fall asleep.

Let’s look at a typical day for an adult:

Say it starts getting dark around 9:00 pm. Once they turn out all the lights and put away their phones, it’s dark enough for melatonin production to begin. This continues for the next several hours.

Melatonin levels peak at some point during the middle of the night. As it begins to get light outside, melatonin production begins to slow down. By 8:00 a.m., the amount of melatonin in an adult’s blood is barely detectable. This closes out the cycle, and makes them feel awake and ready to take on the world!

Did you know? Melatonin is also produced in plants. In the plant kingdom, melatonin acts as a first line of defense against certain kinds of substances that can damage plant tissue.

Parents vs. kids

Just like your parents’ bodies, your body produces melatonin due to a lack of light. But there is one big difference between you and your parents: the timing of your melatonin production.

The circadian rhythm of a young child and of an adult are, on average, more or less in sync. So, if it starts getting dark around 8:00 p.m., your parents and your younger siblings may get sleepy and be ready for bed by 9:00 p.m.

As you go through puberty, your internal body clock shifts about three hours backwards. So, if it gets dark around 8:00 p.m., your adolescent brain won’t start pumping out melatonin until 11:00 p.m.! Scientists aren’t entirely sure why this happens, though it is likely related to the hormonal changes we all experience during our early teenage years.

If production of this sleepy-making hormone shuts off approximately ten hours after it starts, that means your parents are up early and ready for a 9:00 a.m. start to their workday. But for you, 7:00 a.m. is like the middle of the night!

Did you know? The delayed sleep phase doesn’t just affect teenage humans. Almost all pubescent mammals get hit with it!

Your biology seems to be working against you getting to school on time! What can you do to wake up more easily in the morning? Studies have shown that there are two big changes you can make to help sync your body’s clock to the clocks at school:

  1. Minimize nighttime exposure to artificial light. Make sure your phone, television, and computer are turned off. Remember, once your eye detects bright light, melatonin production shuts down!
  2. Don’t sleep in on the weekends. This may seem strange - shouldn't you be catching up on all that sleep you missed during the week? No! Waking up at a dramatically different time of day can confuse your body’s biological clock, making it even tougher to wake up on weekdays. The healthiest way to sleep is to pick a schedule, and stick to it!

Did you know? A study based in Quebec found that both excessively long sleeping times (nine to ten hours per night) as well as excessively short sleeping times (five to six hours) were associated with weight gain. This could lead to higher risks of diabetes and heart disease.

So if you’re just too tired to pay attention in school, remember that’s it’s not entirely your fault - it’s just the way your brain works. Also remember that there are things that you can (and should!) do to help yourself. Studies have shown that if you’re getting a good night’s sleep on a regular basis, you are more likely to score higher on tests, are less likely to miss class, and have a lower chance of developing a mood disorder such as depression. So get your beauty sleep - it makes for a beautiful brain!

Learn more!

Melatonin (2016)
D. Goodsell, PDB-101

Bright Screens, Bad Sleep (2015)
A. Zhou, CurioCity

Melatonin: Nature’s most versatile biological signal? (2006)
S.R. Pandi-Perumal et al., Federation of European Biomedical Societies Journal 273

Sleep and teens
UCLA Health

Kate MacDonald

I am a third year student at the University of British Columbia (UBC) in Vancouver, working toward a degree in cell and developmental biology. Early in my second year, volunteering in a genetics lab sparked my passion for research, and I was driven to explore a career in cellular biology. I am beginning work on my undergraduate thesis, and I plan to pursue an MSc after I graduate. Outside of the lab, I am enthusiastic about science outreach, writing and volunteering for Let’s Talk Science. I also host a series of biodiversity-themed YouTube videos for the Beaty Biodiversity Museum at UBC.