Sleep Quantity vs. Sleep Quality: Which One Makes the Biggest Difference?

Sleep can be a confusing thing.

Some days, you’re so tired you wish your bed would swallow you whole despite sleeping for 8 hours.

But on other days, you wake up ready to tackle the day after sleeping for 6 hours. 

What’s the deal? It’s unclear on the surface — but dig into the research, and you’ll find that two primary factors determine how well you snooze: sleep quantity and sleep quality. 

Read on to learn more about these metrics and determine which is the most critical for you to work on to improve your sleep.

Sleep quantity is defined as the number of hours of sleep required to to restore your energy fully.

According to the National Sleep Foundation, 7 to 9 hours is the ideal sleep quantity for adults aged 18 – 64⁽¹⁾. 

That said, the number of hours you sleep may vary depending on your age, lifestyle choices, and overall health. 

To determine the correct sleep quantity for you, assess yourself based on your answers to these questions:

Sleep quality refers to how well you sleep.

Life Hack says one way to wake up feeling rested is to get as much REM sleep as possible⁽²⁾. The REM sleep stage is the phase wherein you dream. You need to enter this stage in the sleep cycle for quality sleep. 

While more challenging to measure than sleep quantity, the quality of your sleep can be determined by assessing how closely you match the following statements:

• You fall asleep in no more than 30 minutes

• You spend at least 85% of your sleeping time in your bed

• You wake up only once per night, if at all

• If you wake up in the middle of the night, you’re asleep again in no more than 20 minutes 

If none of those statements apply to you, your poor sleep quality is likely the primary reason you have trouble sleeping.

You may need more help in one area than the other, but the perfect formula for healthy sleep combines both sleep quantity and quality.

Without the proper quantity of sleep, you’ll fail to function. However, adequate sleep quantity combined with poor sleep quality will leave you exhausted and impact your alertness during the day.

Sleep Doctor says not getting enough of zzzs leads to sleep deprivation. Lack of sleep increases your risk of health issues like heart problems, type 2 diabetes, depression and obesity⁽³⁾.

If you want to improve your sleep quantity and quality (and you should!), here are five tips to help you do it:

Establish a sleep-inducing environment in your room by making it quiet, dark and cool around bedtime. 

Use earplugs or a white noise app/appliance to counter ambient noise. Heavy curtains or an eye mask can block the light and help you fall asleep faster. As for your room’s temperature, keep it between 60 and 75°F. 

Another vital thing to do is keep your electronic devices and work materials outside the bedroom. This will help you associate your bedroom with sleep, putting your mind at ease and ensuring you get ample sleep.

If you need detailed advice on how to get these done, read these articles:

• How to Make Your Bedroom Darker

• Are The Colors in Your Bedroom Helping You Sleep (or Keeping You Awake)?

• Noise Pollution Is Killing Your Sleep - Here’s What You Can Do About It

If you’re generally not asleep within 20 minutes of your head hitting your pillow, leave your bed and do something that relaxes you in another room. 

For instance, you can play music or read a book until you’re sleepy or tired. Keep the lights dim to avoid messing up your internal clock. For similar reasons, stay away from noisy areas and electronic devices.

Exercising for even 10 minutes a day can positively impact the quantity and quality of your sleep. It can also reduce the risk of developing sleep disorders like sleep apnea. 

Just make sure to exercise at least 3 hours before you sleep. According to Develop Good Habits, exercise stimulates your body. Plus, your adrenaline levels and body temperature increase. These combined make it difficult for you to relax before bedtime⁽⁴⁾.

Start and keep a sleep log. Every evening and morning, jot down your bedtime, wake time, duration of your sleep and the number of times you woke up.  

You can also include the activities you did throughout the day and the foods you ate to determine how they affect your sleep. 

You or the sleep medicine professional with whom you share this log, may be able to determine which factors improve or compromise your sleep quality.

Consider a professional sleep assessment. It help identify sleep disorders like periodic limb movement, sleep apnea,  narcolepsy, restless legs syndrome and insomnia, among others. You'll also get a proper medical diagnosis. Read this article to learn more: Considering a Sleep Study? Here’s What to Expect.

Sleep quantity and quality are inextricably linked. 

To sleep as well as possible, you need to optimize the amount of time you sleep and the things that impact the quality of your sleep.

Which of our sleep optimization tips will you try tonight? Did we miss any of your go-to strategies?

Sources:

(1) “How Much Sleep Do You Really Need?" National Sleep Foundation, www.thensf.org/how-many-hours-of-sleep-do-you-really-need/. Accessed 25 March

(2) Phebus, Angelina. “Quality or Quantity? Why Don’t You Sleep On It." Lifehack, www.lifehack.org/643556/quality-or-quantity-why-dont-you-sleep-on-it. Accessed 25 March 2024.

(3) "Sleep Deprivation: Definition, Symptoms, & Effects" Sleep Doctor, sleepdoctor.com/sleep-deprivation/ Accessed 25 March 2024.

(4) "17 Healthy Ways to Fall Asleep Earlier" Develop Good Habits, www.developgoodhabits.com/sleep-before-midnight/. Accessed 25 March 2024.