Since everyone’s sleep patterns and sleep needs vary, there is no one-size-fits-all definition of “good sleep.”
Determining whether you’re getting a good night’s sleep can be tricky, especially when it isn't just about logging a certain number of hours as many think. However, by tracking your sleep, you can prioritize sleep quality over quantity and begin to learn what good, restful sleep truly is.
Broadly speaking, people “feel" good sleep physiologically, even if they can't quite define what it looks like (the number of hours spent in bed or amount of time spent asleep).
“After a good night of sleep, physically your body will feel more inclined to move," says Jeanine Joy, Ph.D., SleepTips.org sleep expert. “Mentally, it will be easier to focus, and you will think with greater clarity."
In addition, the National Sleep Foundation has pinpointed a few signs of good sleep:
- Falling asleep in under 30 minutes.
- Remaining asleep for 85% of the night.
- Remaining awake for less than 20 minutes if up in the night.
If you take longer than an hour to fall asleep or wake up four or more times and stay awake for longer than 40 minutes in the middle of the night, chances are you’re not getting “good” sleep, regardless of how many hours you log.
How to Measure a Good Night’s Sleep
So, what is considered a good night’s sleep? And how will you know if you’re getting it? Thanks to a measurement model called the Pittsburgh Sleep Quality Index (PSQI), we have a way to truly quantify good sleep. Previously a self-reported questionnaire, the PSQI measures sleep effectiveness. In this model, the number of hours you're spending in bed becomes moot, and the quality of sleep you’re getting reigns supreme.
The PSQI measures seven components of sleep to get to a total overall (or “global") score:
- When you go to bed
- Consistency of your bedtime
- How long it takes you to fall asleep after you go to bed
- How much sleep you actually get (not just time spent in bed)
- What time you get up
- Whether you wake up during the night
- Whether you have difficulty returning to sleep after waking up during the night
- Whether you need to use the bathroom in the middle of the night
If your PSQI score reveals room for improvement, there are a few steps you can take to improve your sleep quality and quantity on a regular basis:
1. Effectively manage stress.
Stress can quickly deplete the energy reserves provided by a good night's sleep, but effective stress management can go a long way to helping you get better sleep. If therapy is cost-prohibitive, there are many low-cost ways to manage stress, such as meditation, yoga, regular walks and exercise, and journaling (especially before bed).
2. Turn out the lights.
Chances are, you’ve heard about the detrimental effects of blue light on sleep. If you already put your phone in another room at night but still feel sluggish the next day, Joy recommends avoiding exposure to all bright light late in the evening. Harvard Health Publishing recommends dodging blue light at least 2-3 hours before bedtime. Other ways to wind down include avoiding caffeine after noon, eating a lighter dinner and taking a warm shower or bath 90 minutes before bed.
3. Keep a watch on your sleep.
Devices with actigraphy—a non-invasive sensor for monitoring human rest/activity cycles— can track how well you sleep. But you don't have to spring for a FitBit or Apple Watch.
“You can get a watch with actigraphy that measures your sleep for as little as $20," Joy recommends. “Every morning, check the app to see what the watch says. The data will help you recognize attributes of a good night's sleep and how a good night's sleep feels." Once you know what’s working for your body and what’s not, you can do more of the positive and less of the negative.
You can sleep well and still feel lethargic the next day. Though often correlated, sleep deprivation and fatigue are two separate issues. Sleep deprivation is defined as a chronic lack of sleep, while fatigue is a temporary condition of feeling tired. You can feel fatigued for a variety of reasons, such as physical and mental exertion, dehydration, travel and stress. However, sleep deprivation and fatigue frequently get confused because the culprits for both are often the same. Allergies, medications, lack of exercise, poor nutrition, and cumulative sleep debt can all lead to sleep deprivation and temporary fatigue.
So if you're getting "good sleep" and continue to wake up feeling tired, try getting more exercise, eating more fruits, vegetables and whole grains, drinking more water, and practicing good sleep hygiene. If all else fails, consult with your doctor.