When most people think about sleep, they focus on the number of hours they’re in bed. The common wisdom is that we need about eight hours each night — and while that number can be a useful guideline, it doesn’t tell the whole story.
As a health coach, I see this all the time. Some people sleep nine or ten hours or more, but wake up exhausted, foggy, or irritable. Others may sleep only six or seven hours, yet they feel rested, focused, and ready for the day. The difference is in the quality of their sleep.
For decades, research has shown that poor sleep quality increases the risk of chronic disease and poor health outcomes. A concept analysis in Nursing Forum cites a 1974 report that good sleep was “just as important to patients as proper nutrition.”
What is Sleep Quality?
Sleep quality as defined by research is “an individual’s self-satisfaction with all aspects of the sleep experience.” While that may seem vague, it points to the fact that sleep quality is individualized. Thus, you can function very well on 5 hours of sleep while your friend requires 9 hours of sleep to feel her best.
“Good” quality sleep includes feeling rested, having normal reflexes and positive relationships. “Poor” sleep quality is defined as daily fatigue, irritability, daytime dysfunction, poor reflex responses and increased caffeine and alcohol intake.
Sleep quality covers five different components: physiological, psychological, behavioral, environmental and physical. This is why when we don’t sleep well, sometimes we just can’t point to one thing.
The Science of Sleep Quality
Sleep isn’t one long, uniform state. It happens in cycles, moving through different stages:
- Light Sleep (Stage 1 & 2): Prepares your body for deeper stages.
- Deep Sleep (Stage 3): Where physical repair, muscle recovery, immune strengthening, and hormone regulation occur.
- REM Sleep: Critical for brain health, emotional processing, and memory.
When sleep is uninterrupted and balanced, you cycle through these stages multiple times per night. This process is what restores your body and mind.
Poor sleep quality — caused by frequent waking, shallow sleep, or sleep disorders — disrupts this cycle. Even if you spend many hours in bed, your body misses out on the restorative benefits.
Why Quality Wins Over Quantity
Here are the main things good sleep quality gives us:
1. Energy That Lasts
A full night of high-quality sleep provides steady energy throughout the day. Poor-quality sleep leads to mid-afternoon crashes, cravings for caffeine or sugar, and that constant feeling of running on empty.
2. Hormone Balance
Good sleep helps regulate cortisol (your stress hormone), insulin (blood sugar control), and appetite hormones like leptin and ghrelin. Poor-quality sleep throws them off, which is why clients often notice increased hunger, sugar cravings, or stubborn belly fat when they’re not sleeping well.
3. Brain Health and Focus
Quality sleep supports memory, problem-solving, and learning. Without enough deep REM cycles, your brain struggles with focus and decision-making. That’s why someone can “sleep in” yet still feel foggy and scattered.
4. Mood and Resilience
You’ve probably noticed that lack of good sleep makes small problems feel bigger. Quality sleep stabilizes mood and improves emotional resilience. Poor quality is linked to irritability, anxiety, and even depression.
5. Immune Strength
During deep sleep, your immune system releases proteins that help fight infection and reduce inflammation. If your sleep is shallow or broken, your body’s defenses take a hit, leaving you more vulnerable to illness.
How to Improve Sleep Quality
There are many great tips to improve your sleep, but I’ll focus on three: sleep routines, blood sugar stability and letting go of worry.
Keep a Bedtime Routine
A bedtime routine signals to your brain and body that we’re getting ready to rest. About 45 – 60 minutes prior to bed, you can:
- Dim the lights
- Read a physical book
- Perform gentle stretching exercises
- Create a cooler environment
- Jen suggested many more tips in her blog Rest & Restore with Sleep: The Importance of Zzzzs
Keep Your Blood Sugar Stable
A balanced evening meal with protein, healthy fats and complex carbs helps prevent 2 a.m. wake-ups from blood sugar dips. This also includes not eating or drinking anything but water 2 – 3 hours before bedtime.
Let Go of the Day’s Worries
One of the biggest barriers to high-quality sleep isn’t physical at all — it’s mental. When we worry, our nervous system stays in “alert mode” and makes it harder to fall into the deep, restorative stages of sleep. While it takes practice, letting go of those thoughts helps calm the mind and signals to the body that it’s safe to rest.
If this is an area you’d like to work on, here are some things to try:
1. The “Brain Dump” Journal to clear mental clutter
- Keep a notebook by your bed.
- Spend 5 minutes writing down everything on your mind — tasks, worries, reminders.
- End with one VERY POSITIVE thing you’re grateful for
2. The 4-7-8 Breathing Method – My favorite way to calm the mind and body
- Do this right after you’re settled in bed.
- Inhale through your nose for 4 seconds.
- Hold your breath for 7 seconds.
- Exhale slowly through your mouth for 8 seconds.
- Repeat for 3–5 cycles.
3. Make a “Worry Appointment” earlier in the day
- Set aside 15 minutes (that’s all!) to contemplate your concern.
- Write it out, think it through, and ask yourself, “What can I do about this tomorrow?”
- Write down what you’ll do tomorrow.
- When your mind tries to worry at bedtime, remind yourself that you’ve already got a plan for tomorrow.
A Client Story
I worked with a woman in her late 60s who slept 9–10 hours every night but was just exhausted all day long. She struggled with excess weight and knew she was relying on coffee in the mornings and sugar in the afternoons. She assumed her fatigue was due to her “getting older.”
When we reviewed her sleep history, she explained that she woke up multiple times at night. Sometimes we could attribute it to blood sugar dips and sometimes from stress, but she always had a hard time getting back to sleep because her mind would start to worry.
We focused on just a few things:
- Eating more protein at dinner
- Reducing, then eliminating, alcohol
- Refraining from using her iPad within an hour before bedtime
- Creating and keeping a simple bedtime routine
In just a few days, she noticed she woke up less. After two months, she was sleeping just 7–8 hours but felt more rested. Her mood improved, she felt less irritable and “snappy,” and she gave up her afternoon sugar habit.
Her total sleep hours decreased — but her sleep quality improved.
Final Word
If you struggle with fatigue, sugar cravings or brain fog despite spending enough hours in bed, it might be time to focus less on the quantity of your sleep and more on the quality.
By giving your body what it needs for deep, uninterrupted rest, you can wake up feeling refreshed and restored no matter what the clock says.
And if you’re interested in learning how sleep devices use data to guide you towards more quality sleep, check out Stacy’s blog on Sleep Tips from Sleep Devices.
Resources:
Nelson KL, Davis JE, Corbett CF. Sleep quality: An evolutionary concept analysis. Nurs Forum. 2022; 57: 144-151. doi:10.1111/nuf.12659
Do you need help getting quality sleep?
If you’re tired no matter how much sleep you get and want help making changes, sign up for a free phone consultation to see if our Health Coaching services might work for you.
Nutrition therapy is not intended as a diagnosis, treatment, prescription, or cure for any disease, or as a substitute for medical care. Our nutrition therapists are not licensed medical providers. Nutrition plans are not intended as a substitution for traditional medical care, nor should be interpreted as medical advice, but instead is an adjunctive and supportive therapy.