Why Sleep Matters More Than You Think
- Francine Park, MD
- Jun 20
- 4 min read
Updated: Jul 7
Sleep, Reimagined – Post 1
The Power of Sleep
A lot of people treat sleep like it’s not that important. We push through late nights, use caffeine to stay awake, and act like rest is something we can skip. But what if sleep is actually one of the best tools we have to feel better, think clearly, and take care of our mental health?
The Role of Sleep in Mental and Physical Health (Why Sleep Matters)
Sleep is not just rest—it’s a biological necessity. Like food and oxygen, our brains and bodies need sleep to survive and thrive. During sleep, especially in deep and REM stages, your brain and body carry out vital processes that protect and optimize nearly every system in your body.
Fun fact: Just one all-nighter can reduce your ability to form new memories by up to 40% (Walker & Stickgold, 2006).
Brain Detox & Cognitive Function
Cleans your brain: Deep sleep activates the lymphatic system, which flushes out waste products like beta-amyloid, a protein linked to Alzheimer’s disease (Xie et al., 2013).
Builds memory: Both deep and REM sleep help your brain organize and store memories—both facts and emotional experiences.
Improves learning: You process and integrate new information while you sleep.
Mood Regulation & Mental Health
REM sleep is your brain’s emotional processing time. It helps reduce reactivity, stress, and emotional overload.
Chronic sleep deprivation increases the risk of anxiety, depression, and burnout.
Treating insomnia often improves mood—even without antidepressants (Baglioni et al., 2016).
Hormone Balance & Metabolism
Sleep regulates important hormones:
Cortisol (stress)
Ghrelin (makes you hungry)
Leptin (makes you feel full)
Insulin (regulates blood sugar)
Poor sleep can lead to increased cravings, blood sugar issues, and weight gain.
One study showed that just a week of short sleep mimics insulin resistance seen in prediabetes (Spiegel et al., 1999).
Immune Function & Inflammation
During sleep, your body releases cytokines that fight off illness and reduce inflammation.
Lack of sleep increases risk for colds, slower healing, and even long-term inflammation-related diseases like depression and heart disease.
People who sleep fewer than 7 hours per night are almost three times more likely to catch a cold compared to those who get 8+ hours (Cohen et al., 2009).
Cellular Repair & Longevity
Sleep triggers growth hormone release, which helps rebuild tissues and muscles.
Studies suggest short sleep may speed up biological aging by shortening telomeres—the protective caps on your DNA.
Sleep vs. Sedation: There’s a Difference
Some people use sleep medicine to fall asleep, but being “knocked out” isn’t the same as real, natural sleep. Sleep happens in stages, including deep sleep and dream sleep (called REM). Deep sleep dominates the beginning of the night, and REM sleep increases the longer you are asleep. If you don’t get enough of each stage, your brain doesn’t get the full benefit—even if you’re in bed for 8 hours.
Fun fact: If you wake up too early, you're often missing REM sleep. That can leave you feeling emotionally off the next day.
How Poor Sleep Affects Your Day
Most people don’t say, “I’m missing REM sleep.” They just say:
“I can’t focus.”
“I feel down or anxious.”
“I’m irritable with people I care about.”
That’s because sleep shapes how we feel all day long. In fact, many people who struggle with depression or anxiety also have trouble sleeping—and the two can make each other worse.
Your Body Has a Sleep Clock
Your sleep is guided by two main things:
Sleep pressure: the longer you’re awake, the sleepier you get
Your body clock (circadian rhythm): tells your body when it’s time to sleep and wake up
This clock can be thrown off by screen time, late-night eating, or inconsistent sleep schedules. It also explains why you may get sleepy at certain times every day—even if you slept enough the night before.
Insomnia Is More Than “Not Sleeping”
Many people think of insomnia as simply struggling to fall asleep. But it's more complex—and it can become a chronic cycle.
The Sleep Hypervigilance Model explains it:
Predisposing traits: anxiety, trauma, high sensitivity
Triggers: life changes, illness, stress
Perpetuating habits: napping, excess time in bed, worry about sleep
This isn’t a flaw in your willpower—it’s your nervous system reacting to perceived danger. And it can be unlearned.
What If We Treated Sleep With Respect?
A sleep expert once said:
“Good sleep isn’t just a health issue. It’s also an ethical one.” – Dr. Rafael Pelayo
We live in a world that rewards overworking and skipping rest. But when we ignore sleep, we often end up tired, moody, and disconnected—from ourselves and from others. It's why sleep matters. Taking sleep seriously isn’t selfish. It’s actually one of the kindest things you can do for your brain, your heart, and the people around you.
What’s Coming in This Series
In the next posts, we’ll talk about:
How anxiety affects sleep (and vice versa)
What good sleep habits really look like
How your daytime choices help (or hurt) your sleep
When to seek help
How to create peaceful bedtime routines that actually work
Want to Learn More?
Walker, M. Why We Sleep. Scribner, 2017.
American Academy of Sleep Medicine. Patient Resources.
National Institutes of Health. Brain Basics: Understanding Sleep
References:
Xie L. et al. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373-377.
Baglioni C. et al. (2016). Sleep and mental disorders: A meta-analysis. Psychol Bull. 142(9):969–990.
Walker MP, Stickgold R. (2006). Sleep, memory, and plasticity. Annu Rev Psychol. 57:139–66.
Spiegel K, Leproult R, Van Cauter E. (1999). Impact of sleep debt on metabolic and endocrine function. Lancet. 354(9188):1435–1439.
Cohen S, et al. (2009). Sleep habits and susceptibility to the common cold. Arch Intern Med. 169(1):62–67.
