Quality vs Quantity of Sleep: Which Is More Important?
9 min minutes read

Quality vs Quantity of Sleep: Which Is More Important?

Key Takeaways:

  • Sleep quantity refers to the number of hours of sleep you get each night while sleep quality refers to how well you slept. Sleep quality is a superior metric to sleep quantity because the amount of sleep you get each night is only one indicator of sleep health, whereas sleep quality is made up of several factors. 
  • Sleep is vital to all functions and processes in your body. Lack of sleep could result in greater fatigue, decreased cognitive functioning, mood shifts, lower immune function, changing metabolism, and more.
  • You can improve your sleep quality and quantity by focusing on your sleep hygiene, prioritizing your sleep schedule, using a sleep tracker to gain better insight, reducing stress levels, and talking to your doctor if you need help.

According to the Centers for Disease Control and Prevention (CDC), over a third of all American adults aren’t getting enough sleep.1 Factors like rising stress levels, modern-day technology, and “revenge bedtime procrastination” (or the sacrifice of sleep for free time at the end of the day) are among the causes. It might feel harmless to skip an hour or so of sleep for a scroll through TikTok or binge-watch of your favorite show. But getting a good night’s rest is hands down one of the best things you can do for your health. And that’s because it’s during sleep that your body recovers, resets, and repairs itself to prepare you for a new day. 

Although you might feel like sleep is your body powering down, it’s actually quite the opposite. Every process and function in your body struggles without sleep.1 Poor sleep quality and quantity over time could result in mood shifts, memory loss, cognitive decline, and a greater risk of health conditions like type 2 diabetes, high blood pressure, heart disease, depression, and more.2 3

While sleep quantity is important, it’s not the only factor. Both the quantity and quality of sleep you get each night are big predictors of your health. So what’s the difference between the two and how do you know if you’re getting good quality sleep? 

What Getting A Good Night’s Rest Really Means 

Sleep quantity refers to the number of hours of sleep you get each night.4 And according to the experts, adults need around seven to nine hours.5 Although research suggests that women need even more sleep due to a higher likelihood of insomnia, anxiety, depression, and other sleep-impacting disorders.6 Sleep duration is easy to measure, making it the default metric for sleep health. But the number of hours spent in bed means very little if the quality of that sleep is poor. In other words, sleep quantity measures how much you slept while sleep quality measures how well you slept.7

How to Measure Sleep Quality

As you can imagine, measuring sleep quality is a bit more complicated since it’s far more subjective than quantity. But like all subjective forms of measurement, it’s not perfect and it’s going to look different from person to person.

Although there's no definitive definition, a generally agreed upon “measurement” of sleep quality includes the below characteristics:4 7

  • Sleep Onset Latency: You fall asleep within 30 minutes of getting into bed.
  • Sleep Continuity: You typically sleep through the night without waking up. If you do wake up in the middle of the night, you fall back asleep within 20 minutes.
  • Sleep Efficiency: You spend more time sleeping than you do trying to sleep.
  • Sleep Quantity: You’re getting the recommended amount of sleep on average per night.
  • Sleep Timing: Your sleep matches your natural circadian rhythm or internal clock. 
  • Alertness During Waking Hours: You feel rested and refreshed when you wake up and have energy and full cognitive capacity throughout your day. 
  • Sleep Satisfaction: You feel satisfied with the sleep you’re getting each night. 

Sleep Stages

Another huge factor in sleep satisfaction and quality is the time you spend in each stage of sleep. After all, sleep isn’t one uniform experience. There are four sleep stages that you progress through four to six times a night, and each one plays a crucial role in helping you feel refreshed and ready to tackle your day:8 9

Sleep stages

Focus On Sleep Quality Over Quantity

Sleep quality is a superior metric to sleep quantity because the amount of sleep you get each night is only one indicator of sleep health. As we’ve discussed, sleep quality takes a lot more into account than just the duration of sleep. Sleep quality considers the sleep stages and other metrics like alertness, efficiency, continuity, satisfaction, and more.10 In other words, sleep quality includes sleep quantity while also looking at the big picture of your sleeping habits.

Can Poor Sleep Really Impact My Health?

What exactly happens to your body if you miss out on those crucial hours of high-quality sleep? Regularly disrupting your sleep quantity and quality can lead to several health impacts including:

  • Greater fatigue: Probably the most obvious side effect of a lack of sleep is the feeling of exhaustion. Without sleep, you won’t feel rested or motivated to tackle your day. 
  • Decreased cognitive functioning: Without enough sleep, you may also struggle with cognitive tasks like focus, concentration, and memory.10
  • Mood shifts: Lack of sleep can make regulating emotions harder, so you’re more likely to feel frustrated, angry, or stressed out more often than usual.7
  • Struggling immune function: Without the necessary reset that sleep offers, you’re making it harder for your body to defend itself against harmful pathogens. This makes you more susceptible to illness. 
  • Poor skin health: Lack of sleep can cause acne, breakouts, puffy or red eyes, and dark circles.7
  • Stress on your cardiovascular system: Poor quality sleep over time could result in potential long-term impacts on the heart, including increasing the risk of hypertension, high cholesterol, heart disease, and stroke.4
  • Changing metabolism: Lack of sleep can also affect the hormones in your body responsible for a healthy metabolism. These hormones, called leptin and ghrelin, help regulate your hunger response. Without enough sleep, those hormones are out of whack which may cause your body to crave more calories than it actually needs.11

    How Can I Make Better Sleep a Reality?

    Many factors can get in the way of a good night of sleep, including sleep disorders like sleep apnea or insomnia, high stress levels, medical conditions, and more. Gender could also play a role in sleep quality. On average, women are more than twice as likely to struggle with sleep issues compared to men.12 While some factors are outside of your control, there are a few actions you can take to make better sleep a reality: 

    Improve Your Sleep Hygiene

    One of the biggest factors you do have control over is your routine. Sleep hygiene, like dental hygiene or personal hygiene, involves small actions you take each day to improve your sleep health.7 This consistency creates habits that help set you up for sleep success. 

    These habits include:

     Establishing a regular sleep schedule: Getting up and going to bed at the same time every day creates an easy rhythm for your body to follow. Especially when you line this up with your natural circadian rhythm or your body’s internal clock.13
     Following a sleep routine: Performing the same actions every night before going to bed helps your body wind down from your day. It also creates a routine that trains your brain to expect sleep as the next step. This could be as simple as a skincare routine, brushing your teeth or washing your face, or journaling every night before bed.13
     Turning down the lights: Melatonin is a hormone the body creates to help trigger sleep. The sun setting is a natural indicator for your body to start creating melatonin. As you’re preparing for bed, you can help with this hormone production by dimming your lights so they’re not as bright. And aim for a dark room as you fall asleep.13
     No screens before bed: Your brain perceives the blue light emitted from your phone and laptop as sunlight. It tricks your brain into thinking it’s still daytime, making sleep more elusive if you immediately go from screen time to sleep time. Instead, try reading a book or practicing meditation for 30 minutes before bed.4 7
     Setting up your space for success: From a comfortable mattress to a white noise machine to black-out curtains, the physical aspects of your room can make a big difference in your sleep quality. It’s worth the time and investment to set yourself up for success.4

      Prioritize Healthy Lifestyle Choices

      But it’s not only the actions you take before bed that matter. The lifestyle habits you’re embarking on throughout your day impact your ability (or inability) to fall asleep and get a good night’s rest. Here are a few healthy habits to implement for better sleep:

      • Limiting caffeine and alcohol: Both caffeine and alcohol work against your sleep goals. You can improve your sleep by cutting back on your alcohol intake and avoiding caffeine within five hours of going to bed.7
      • Getting regular exercise: Working out is exhausting, which helps your body fall asleep faster. Not only that but exercise can release mood-boosting endorphins and help lower your stress levels. This could help reduce the time spent tossing and turning.14
      • Soaking in the sun: Spending time outdoors can help expose you to vitamin D which can help encourage your body’s natural circadian rhythm, making sleep easier.13
      • Quitting smoking: Nicotine, like caffeine, is a stimulant. That means it’s counterproductive to sleep, with studies showing a direct connection between smoking and poor sleep quality.15

        Use a Sleep Tracker

        It’s hard to know what to focus on if you’re not getting a full picture of your sleep, and a sleep tracker can help you do that. Without a sleep tracker, the only measurement of sleep quality you have is how you feel when you wake up. 

        But you can uncover a lot more insight with access to data like sleep duration, sleep stages, sleep patterns, and health vitals like resting heart rate and heart rate variability. This helps give you a clear picture of your sleep zones each morning so you can identify disturbances and actively work to fix them. 

        Reduce Levels of Stress & Anxiety

        Poor mental health and sleep quality are connected in what often feels like an unbreakable cycle. Mental health conditions like anxiety and depression can make falling asleep difficult. This then leads to poor sleep quality which then contributes to more anxiety and depression. And the cycle continues.7

        Prioritizing your mental health can help you break free of the cycle. Although this can feel easier said than done there are things you can do to help like cognitive behavioral therapy, meditation, regular exercise, meditative movements like yoga or tai chi, and more. 

        Talk to Your Doctor

        There could be certain factors impacting your sleep quality that you have very little control over, such as a sleep disorder or an underlying health condition. In this case, your doctor will be your best resource for managing your health. They can help diagnose the issue and suggest lifestyle or medication treatment options to help improve your sleep quality.7

        The Takeaway

        Sleep is vital to all areas of your health. While it’s normal to focus on the number of hours you’re sleeping, that’s not the only piece of the puzzle for maintaining high sleep quality. An efficient and continuous night of sleep where you progress through all four stages of sleep (multiple times) is important. To boost your sleep quality, build a solid sleep routine, prioritize sleep as an important part of your day, use a sleep tracker to gain valuable insight, focus on stress reduction, and talk to your doctor if you need help. 


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