What is sleep health?, The Research Life.
We normally ask our friends and loved ones how they’re doing. I like to also check in and ask how they’re sleeping. They often tell me how many hours of sleep that they got the night before. That’s the most common metric that people use to estimate how well they slept: time. While sleep duration is important, sleep health is about much more than how much time we spend asleep. Our sleep health includes several sleep dimensions that some researchers have summarized as Ru SATED1. The primary dimensions are Regularity, Satisfaction, Alertness, Timing, Efficiency, and Duration.
Why does sleep health matter?
The way that we sleep is linked with many other dimensions of health, including physical activity, mental health, brain health, and cognitive function 2. When we sleep, our bodies are taken care of in a way that doesn’t involve our conscious involvement. Sleeping well is one way to achieve long and healthy lives by helping to maintain our bodies as a whole.
The sleep health audit: how healthy is your sleep now?
The Ru SATED sleep health measure is designed to quickly assess dimensions of sleep health that are summarized above. I will detail different aspects of sleep health below.
Are your sleep/wake times on a regular schedule?
An easily missed dimension of sleep health is the consistency of the timing that we go to bed and wake up each day. The stability of our sleep/wake schedule can be thought of as sleep regularity. If people go to sleep at 10 PM on weekdays, but 2 AM on weekends, their sleep patterns are irregular. Similarly, people who have different wake times on work days and off days have inconsistent sleep schedules. This does not imply that people must go to bed at the same time and wake up at the same time on the minute of every day, but having a regular schedule is a component of sleep health.
Are you satisfied with your sleep?
Sleep satisfaction is simply how people rate their sleep quality. It is a self-reported measure for how people feel about their sleep. For example, if I wake up and feel groggy or tired after waking up several times during the night, I would likely rate my sleep quality as poor. However, if I slept through the night and felt refreshed, I would rate my sleep quality more highly. There is some evidence to suggest that sleep satisfaction is linked with deep sleep or slow wave sleep. When our sleep is deeper and more restorative, we tend to feel more satisfied with how we slept.
Can you stay awake during the day?
Good sleep health involves being awake and alert during the waking day. Feeling tired or drowsy during the day is often referred to as “daytime sleepiness.” If after you have slept, you find yourself dozing off in classes, meetings, or during work, this could be an indication of poor sleep health. Even if you feel bored during these events of your day, you may want to make some adjustments to your sleep system if you feel sleepy during daytime hours.
Are you sleeping during the recommended time?
The time that people sleep is also an important indicator of sleep health. According to the Ru SATED idea of sleep health, sleep timing should be situated so that the midpoint of sleep is between 2 AM and 4 AM. A typical sleep schedule for this sleep timing might start at 11 PM and end at 7 AM, making the midpoint of sleep at 3 AM. There are many alternative schedules that fit this. For example, I normally fall asleep around 10–10:30 PM and wake up at 5:30 AM, so the midpoint for my sleep is around 2 AM. The idea for this sleep timing measure is that people typically sleep best during the nighttime hours. This is supported by our internal clocks (i.e., circadian rhythms) and the darkness of the night that allows our bodies to secrete hormones (e.g., melatonin) that promote sleep.
Sleep timing is different for people who work later shifts, and shift work can take a toll on sleep health. While understudied, there are methods to help improve sleep quality in shift workers who have much different sleep timing than others (reviewed here).
Are you sleeping throughout the night?
When we think about sleep health, we should consider sleep efficiency, or how continuous our sleep is in a given night. For example, even if I normally sleep for the recommended 7-hour minimum, that doesn’t guarantee that my sleep is efficient or that I sleep well. My sleep may be broken into several periods because of noise in my room (e.g., my cat running around, traffic) or having to get up to go to the bathroom.
How long are you sleeping each night?
Sleep duration is one of the most common metrics of sleep health. Our sleep duration is how long we spend sleeping during the night. It is important to distinguish sleep duration from time in bed. Just because we might lie in bed while reading or scrolling through social media ( although we shouldn’t), time in bed is not equivalent to time slept. The recommended amount of sleep time is 7 hours or more for most adults. Sleeping fewer than 7 has been linked with many health problems, including heart disease and poor cognitive function, or the ability to think and remember well.
Is your sleep adaptable?
Sleep adaptability is difficult for researchers to assess because it involves how well people sleep under stressful or unfamiliar circumstances. People may sleep well in their beds, but they may find it difficult to sleep in hotel rooms or at a friend’s place. In addition to having trouble adapting to a physically unfamiliar environment, some people tend to have trouble adjusting to stressful situations. For example, becoming a new parent, changing careers, or experiencing global upset (e.g., Covid-19) could all influence how people sleep. The degree of strain that physical or psychological changes place on sleep varies from person to person. Although sleep adaptability is understudied as compared to the other, more commonly measured dimensions of sleep health, one study found that people who maintain sleep regularity in their homes are more likely to sleep well in other environments. In other words, finding a way to maintain consistent sleep at home may aid in sleeping better in other places.
What’s your next step for your sleep health?
Now, we’ve gone through several dimensions of sleep health — regularity, satisfaction, alertness, timing, efficiency, duration, and adaptability. How healthy is your sleep? Is there anything that you need to do to improve your sleep health? If you’re curious to learn more about sleep health, how to sleep better, and how sleep relates to other aspects of daily life, see my list of sleep topics here. And consider subscribing to my email list for regular posts on sleep, focused thought, and the interrelation between the two.
1 The ideas presented here are largely based on this research article that gives a comprehensive definition of sleep health and how it relates to other areas of health.
2 In addition to the above link on sleep health, this research article reviews several studies showing an association between some aspects of sleep health and general health.