by Aaira Gupta

Have you ever wondered why you feel exhausted even after sleeping for eight hours the night prior? This experience is surprisingly more common than you may think. 

40% of healthy teens experience regular sleepiness and over 70% of teens in the U.S. don’t get the recommended amount of sleep. 

Because of how the teenage brain is wired, the way our sleep cycle works actually explains a lot about why we feel so tired.

In this blog post I am going to be breaking down the real science behind teen fatigue as well as what you can do about it. 

Why is sleep so important? 

Before I explain why you always feel fatigued, it is important to acknowledge how much we benefit from a healthy sleep schedule.  

You’re probably well aware that sleep is an essential part of overall health and well being. But what exactly does it do for us? 

Sleep is when the mind and body repairs itself from the demands of the day. Not only does it improve our cognitive functions, mood, and overall health, it also plays a role with memory consolidation.

During sleep, our brain processes information and transfers it to long-term storage which is essential for retaining and learning information. 

So next time you decide to stay up to last-minute study for that AP exam remember that little of what you cram will actually stay in your memory. 

What is our circadian rhythm? 

The circadian rhythm is our body’s natural, internal clock that regulates the sleep-wake cycle. It is what tells us when to wake up, feel hungry, get sleepy, or even when to focus.

When there is a mismatch between our biological clock and the time we go to bed, our sleep quality goes down substantially. 

What many people don’t realize is that teenagers experience a natural shift in their circadian rhythm by a couple of hours. This causes them to feel tired later and want to wake up later in the morning.

While this may not seem like a great shift, it can create a conflict with early school start times and make it difficult for teens to get enough sleep. 

For instance, imagine that a student only starts to feel tired around 1:00 AM and wants to wake up around 9:00 AM. However, their school starts at 7:00 AM, requiring them to wake up much earlier than their body naturally wants to.

This mismatch between their circadian rhythm and required schedule is a classic example of sleep phase delay. 

Release of melatonin, a hormone that promotes sleepiness, is delayed because of the shift (also known as sleep phase delay) which contributes to the later sleep schedule. 

A lack of sleep can negatively impact academic performance, mood, and overall health. Teenagers and parents should recognize that this delayed sleep pattern is not a matter of poor habits or laziness but a normal biological change that occurs during puberty. 

What is sleep debt? 

A lot of people have this misconception that if they sleep well just one night, they won’t feel tired the next day. However, if you usually don’t get enough sleep, one night isn’t enough to reset your brain after days of exhaustion.  

Sleep debt refers to the cumulative amount of lost sleep that occurs when a person does not get enough sleep over a period of time.

This debt can accumulate gradually over time and as it grows it can result in several negative consequences that include an increased risk to accidents and reduced productivity and performance. 

For example, if you get five hours of sleep when you should be getting eight, you’ll have a sleep debt of three hours. If you do this for the next seven days you will end up with a sleep debt of 21 hours.  

Losing sleep a few times is inevitable because of life circumstances but to recover from it you should take naps as needed, sleep more on weekends, develop a night time routine that relaxes and makes it easier for you to fall asleep. 

It is also essential to note that everybody’s bodies are different and thus we all need different amounts of sleep in order to function. While some people function well with 6 hours of sleep, others may need 10 or more. 

It is important to listen to your body and figure out what sleep duration allows you to feel your absolute best!  

Poor sleep quality 

Sleep quality is not the same as sleep quantity. Sleep quantity measures the amount of sleep you get every night while sleep quality measures how well you sleep.  

Even if you get 8 hours of sleep, having low-quality sleep means that you may still feel exhausted after waking up. 

Signs that you have poor sleep quality include: 

• Waking up feeling groggy or tired 

• Waking up multiple times during the night 

• Struggling to fall asleep 

• Having vivid, intense, or nightmarish dreams regularly 

When sleep is insufficient, the body’s restorative processes are compromised.

This results in fatigue and reduced alertness which explains why you may still feel tired even after sleeping the necessary hours. 

Poor sleep quality can have an effect on brain structure and can potentially lead to reduced gray matter density in certain brain regions and affect white matter microstructure. 

Gray matter (which is primarily composed of neuron cell bodies) is essential for cognitive functions such as memory, learning, and thinking. 

Maintaining healthy sleep habits is important for brain health and reduces the risk of age-related cognitive decline. 

How does our brain chemistry impact our sleep? 

Our brain chemistry plays a crucial role in regulating sleep-wake cycles.

Neurotransmitters (chemical messengers that help perform bodily functions) such as GABA, orexin, acetylcholine, serotonin, and others influence when we feel sleepy and when we feel alert. 

The two key hormones involved are Melatonin and Cortisol.  

• Melatonin: produced by the pineal gland, promotes sleepiness; The suprachiasmatic nucleus (SCN) in the brain regulates melatonin production based on light and dark signals. 

• Cortisol: produced by the adrenal glands, cortisol is a part of the body’s stress response. Cortisol levels naturally rise in the morning to help us wake up and become alert. 

Fun fact: Blue light exposure (phone use) before bed suppresses melatonin. 

What happens when there is a hormone imbalance? 

Various factors can cause a change in hormone levels. These factors include artificial light (especially blue light from screens), stress, certain medications, and even the time of year.

When there is a hormone imbalance, it can lead to sleep problems because it would disrupt our sleep-wake cycle. 

For example, someone with high cortisol levels at night will have a burdensome time trying to fall asleep. This is because the hormone makes us feel alert instead of sleepy. 

Additionally, since cortisol is released in response to stress, it prepares our body for a “fight or flight” response by increasing alertness, heart rate, and blood pressure. 

If you’re constantly stressed or anxious your body is likely producing elevated cortisol. This can create chronic stress and keep our nervous system activated. 

The nervous system is our body’s control and communication center. It enables functions such as movement, thought, and sensation.

When this system stays active, sleep, digestion, mood, and energy levels all get affected. You may look rested but your nervous system hasn’t shut off which makes it difficult to fall asleep. 

Lack of movement 

A sedentary lifestyle (prolonged sitting and limited physical activity) is linked to sleep disturbances, poorer sleep quality, and increased sleep latency (the time it takes to fall asleep).  

Ironically, being sedimentary makes us more tired. 

Physical activity directly impacts brain health by increasing the blood flow and oxygen delivery to the brain. This creates better energy and focus. 

Unfortunately in the current times it can be hard to get the recommended amount of exercise each day.

With more academic pressure than ever before teens are now expected to participate in extracurriculars, form passion projects, and know what exactly they want to do in the future on top of getting good grades. 

This results in major brain fog in teens where it is hard for them to think clearly or concentrate. 

This is why teens should make it a priority to get enough movement in their day. Simply walking around more can make a world of difference to their health and sleep schedule. 

Undereating and Overprocessed foods 

Research indicates a strong connection between poor dietary habits and bad sleep quality in several ways. 

1. Nutrient deficiency: Not consuming enough calories can lead to deficiencies in nutrients such as magnesium, zinc, calcium, and B vitamins. These nutrients are crucial for regulating sleep-wake cycles and neurotransmitter production (melatonin and cortisol) 

2. Hormonal imbalance: Undereating can disrupt hormones involved with sleep such as leptin (tells your brain when you’ve had enough to eat) and ghrelin (an appetite stimulant). This may lead to poor sleep quality and increased hunger towards unhealthy foods. 

3. Disrupted sleep patterns: Diets high in processed foods are linked to lighter and less restorative sleep and more frequent awakenings in the middle of the night. 

4. Sugar spikes and crashes: Sugary processed foods can cause rapid fluctuations in blood sugar levels which negatively impacts sleep patterns. 

So next time you reach for that bag of Doritos, take a second to think about what your brain and body may be dealing with afterwards. 

So what can I do? 

We have finally reached the part of the post where I explain what we can actually do to stop feeling tired all of the time. 

Here are several lifestyle choices you can make to drastically improve your sleep schedule: 

• Stick to a consistent sleep schedule: Try to wake up and go to bed at the same time everyday (yes, this includes weekends) 

• Get sunlight in the morning: Getting natural light within the first 30-60 minutes of waking up can help boost morning energy and nighttime melatonin 

• Limit blue light before bed: Try to stop using screens 30-60 minutes before bedtime or use night mode/blue light filters 

• Stop scrolling in bed: Yes, I know this is a tough one. However, your brain associates TikTok and Instagram with simulation, not rest. Try using your bed only for sleep 

• Cut off caffeine by early afternoon: Caffeine can stay in your system for up to 10 hours. Avoid energy drinks and even chocolate after 2-3 PM 

• Keep your room cool and dark: This boosts melatonin levels 

• Move your body during the day: Exercise (even a 10-20 minute walk) can improve deep sleep at night 

If you are constantly tired, it doesn’t mean that you’re lazy or broken. It just means that your brain and body are out of sync and are asking for rest in a way you haven’t been taught to recognize. 

You don’t need a total life reset; that could lead to highly unrealistic expectations and then burnout. It is best to take things one step at a time, and to treat yourself with patience and kindness. 

I highly recommend the book, Atomic Habits by James Clear. In the book he discusses his method on how to make new habits stick and how to break bad habits. I found the book enlightening and it even helped me implement these lifestyle choices in my life for good. 

We all know how important sleep is, but are you ready to prioritize it?

After all, your brain does a lot. It deserves better rest. 

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Sources: 

Felson, Sabrina. “What Is Sleep Debt?” WebMD, 17 July 2023, www.webmd.com/sleep-disorders/what-is-sleep-debt. 

Mandolesi, Laura, et al. “Effects of Physical Exercise on Cognitive Functioning and Wellbeing: Biological and Psychological Benefits.” Frontiers in Psychology, vol. 9, no. 9, 27 Apr. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC5934999/, https://doi.org/10.3389/fpsyg.2018.00509. 

Suni, Eric, and Anis Rehman. “Sleep Quality: How to Determine If You’re Getting Poor Sleep.” Sleep Foundation, 17 Dec. 2020, www.sleepfoundation.org/sleep-hygiene/how-to-determine-poor-quality-sleep. 

“Waking up Tired after 8 Hours of Sleep? – Daytime Tiredness | SleepTest.co.uk.” Https://Www.sleeptest.co.uk/, www.sleeptest.co.uk/still-tired-during-day-after-eight-hours-sleep/. 

“Waking up Tired: Causes, Symptoms, and Treatments.” Www.medicalnewstoday.com, 16 Apr. 2020, www.medicalnewstoday.com/articles/waking-up-tired#causes. 

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