We all know that sleep is an essential human function, allowing our bodies to heal and brains to work correctly. As such, sleep impacts nearly every area of our lives. The Centers for Disease Control declare that in order to maintain optimal health and well-being, adults need 7 or more hours of sleep per night. And yet a recent report found that among American adults, 35.3% sleep less than 7 hours during a typical 24-hour period.
Sleep is something to be concerned about, whether you wake repeatedly after an hour or two, or you regularly sleep the entire night through. Indeed, one of the many mysteries about sleep is how some people can doze so lightly that they’re awakened by a light tap on the door, while others are such heavy sleepers that they can snore through fire trucks wailing down the street.
We started wondering about these kinds of mysteries, so we surveyed 2,700 Americans in 25 major metropolitan areas about their sleep patterns. Here are a few of the striking things we learned:
- Overall, Americans are almost evenly split between light and heavy sleepers (51.6% and 48.4% respectively).
- A slightly greater percentage of women consider themselves light sleepers than men (52.9% vs. 50.3%).
- More parents are light sleepers than non-parents (56.7% compared to 47.9%), which comes as no surprise to anyone with kids.
- Depth of sleep varies by profession. The heaviest sleepers are people who work with animals, architects, and those in the automotive industry. The lightest sleepers are in aviation, followed by workers in oil and gas exploration.
- Among America’s largest cities, there are more than twice as many light-sleeping cities as heavy-sleeping cities, respectively.
- Phoenix residents are America’s lightest sleepers, and San Francisco Bay Area inhabitants are the heaviest sleepers.
We also found a correlation in sleep patterns between married couples where one spouse is a light sleeper and the other is a heavy sleeper, and also in the fact that light and heavy sleepers exhibit different personality characteristics from each other.
These results and others, based on several different variables, show just how alike (and how different) people and their sleep patterns can be. So plump up your pillows, get comfortable, and let’s take a deeper dive into the nighttime habits of light and heavy sleepers across America.
Heavy/Light Sleeping by Demographic
Sleep patterns broken down by age, gender, parenthood, and other demographics
Does a 50-year-old married father of three naturally sleep worse than a 27-year-old single female? Or might their lives’ differing circumstances affect them in ways that somehow make their sleep patterns similar? To answer these and other questions, we asked 2,700 survey takers about their sleep patterns, then broke the numbers down across several demographics.
Our results show almost an even split between light and heavy sleepers around the country. 42.8% of Americans are fairly light sleepers, with 8.8% being extremely light sleepers, while 41.1% reported they’re fairly heavy sleepers, an additional 7.3% being extremely heavy sleepers.
Researchers have found very little conclusive evidence for why people are light or heavy sleepers (aside from the effects of circumstances in their daily lives), but it is known that genetics, lifestyle conditions, and undiagnosed sleep disorders can all play a role in how long, how often, and how deeply we sleep.
A study published in the scientific journal Current Biology suggests that differing effects of noise on sleeping people may be related to sleep spindles, which are brain rhythms that affect a sleeper’s response to external stimuli. People who produced more sleep spindles during quiet nights of sleep developed a higher tolerance to noise during a noisy night of sleep.
Light vs. Heavy Sleepers by Gender
When it comes to gender, women tend to be slightly lighter sleepers than men. 52.9% of women characterized themselves as light sleepers, while 50.3% of men reported that they are light sleepers.
According to the American Academy of Sleep Medicine, women are more likely to experience trouble sleeping at night. Women are also more likely to suffer from insomnia, which can result in excessive daytime sleepiness and a higher degree of difficulty concentrating and remembering things due to the resulting fatigue.
It is suggested that light sleepers spend less time in Stage 3 of sleep, or “deep sleep,” which is why it’s easier for them to be awakened by noise. People who spend most of their night’s rest in Stage 1 or 2, also known as “light sleep,” aren’t fully asleep, meaning their brainwave frequency and body states are not yet fully relaxed. Thus, they’re more susceptible to awakening by some sound or sensation around them.
Parenting and Sleep
We asked 1,200 parents and 1,500 non-parents how soundly they sleep
We split our 2,700 participants into groups by parenting status and asked both the parents (1,200 of them) and non-parents (1,500 of them) whether they were light or heavy sleepers. In results that probably come as no surprise to anyone with kids, the parents tend to be lighter sleepers than non-parents (56.7% to 47.9%).
In general, non-parents don’t need to be as alert as parents because they have no little ones (or slightly older ones) to look after. Because staying on alert is essential to making sure children stay safe throughout the night — on top of responding to cries, requests for water, and searches for missing stuffed animals — getting sound sleep isn’t as easy for parents, especially those of newborns, infants, or toddlers.
A recent study revealed that 68% of its subjects consistently got a full night’s rest (at least 7 hours) before they had a baby — but after having a child, only 10% got the recommended amount of rest. Fortunately, newborns’ sleep patterns start to even out over time, so although parents may not be getting an adequate amount of sleep at first, at least their patterns become more consistent instead of waking up at random hours of the night.
Forty Winks After Work?
America’s Lightest and Heaviest Sleepers by Profession
The results of our survey that examined soundness of sleep across professions revealed a huge variety. People who work in the aviation field are the lightest sleepers (83.3% light sleepers vs. 16.7% heavy), while veterinarians and groomers are the heaviest sleepers (71.4% heavy sleepers vs. 28.6% light).
No direct correlation was revealed between noise levels at work and ease of sleep. People who work in “loud” fields — those that typically involve noisy machines, such as utilities or auto repair — were slightly more likely to be heavy sleepers, though not by a definitive margin. For example, construction workers’ results show only a slight difference between light and heavy sleepers, at 49% and 51%, respectively. Other loud career fields such as oil and gas exploration show significantly more light sleepers (80% light vs. 20% heavy).
While your job may not affect how soundly you sleep, it can definitely affect how much sleep you may or may not be getting. Positions that require you to stay awake overnight while the rest of the country is sleeping — such as air traffic controllers, nurses, and network administrators — are listed among the top jobs that can ruin your sleep. These jobs disrupt the body’s internal sleep clock, and many people have trouble adapting.
America’s Lightest and Heaviest Sleepers
Which cities sleep most soundly?
Where in the country is it easiest to sleep? Our survey results show that light and heavy sleepers coexist within the same regions, but it is worth pointing out that more than twice as many cities in America contain light sleepers (17 cities) as heavy sleepers (8 cities).
To measure the country’s slumber, we devised a scale that ranged from 2, denoting the heaviest sleepers, to -2 for the lightest sleepers. Then we asked each city’s inhabitants where on the scale their heads came to rest.
The San Francisco-Oakland-San Jose region of California has the country’s heaviest sleepers, while Phoenix hosts the lightest sleepers. The two cities with the country’s heaviest and lightest sleepers are only about 12 hours’ drive apart, but apparently there’s a world of difference when it comes to their respective residents’ soundness of sleep. The majority of cities’ sleepers fall decisively in the middle of the scale, spread around the country from Houston to Seattle and Boston to Vegas and points in between.
Interestingly, both the top-ranked cities outpaced their second-place followers by nearly double. The Bay Area returned a score of 1.735 out of 2, surpassing the heavy-sleeping cities that follow it — Miami and Los Angeles, with scores of .825 and .677, respectively — by a rate of nearly two to one. At the other end of the scale, Phoenix sleepers, nearly at the -2 extreme with a score of -1.955, are nearly twice as likely to wake as those in the next lightest-sleeping cities of Chicago at -1.239 and Pittsburgh at -1.042.
No specific correlation has been established between proximity to the ocean and deeper sleep, but the top four cities with the heaviest sleepers — San Francisco, Miami, Los Angeles, and New Orleans — are all coastal locations. One possibility is that the rhythmic sound of whooshing water or lapping waves (even if a sleeper doesn’t consciously register hearing it) can provide a more restful sound pattern for the human brain.
Couples and Sleep
How is it that one person can wake up at the drop of a pin while their spouse can sleep through a hurricane? It’s been said that opposites attract, but does that also hold true when it comes to the differences in how you and your partner sleep? We surveyed participants about their own sleep habits versus their spouses’ habits and found that yes, opposites do indeed attract.
According to survey results, extremely heavy sleepers are almost twice as likely to marry light sleepers as they are to marry those who also slumber deeply. (62.7% vs. 37.3%). Accordingly, extremely light sleepers are more than twice as likely to marry deep sleepers as those who also wake easily during the night. (70.4% vs. 29.6%).
If one spouse is a heavy sleeper, then there’s a great chance that their partner is a light sleeper, or vice versa. This may just be a coincidence — or it could be an unconscious choice responding to a need for balance in the household, ensuring that at least one person will always be able to respond to a middle-of-the-night emergency. From this knowledge, the question naturally arises: How can these opposites both sleep soundly in the same bed?
According to experts, the key to achieving a better sleep experience for both partners is to first identify any issues preventing deep sleep, and then to make corresponding changes in bedroom conditions. For example, if one spouse can’t sleep well on a certain type of mattress that the other prefers, it may be beneficial to invest in a different high-quality mattress that offers comfort to both parties. If the issue lies with something that can’t be changed or modified in the features of the bedroom, sleeping in separate bedrooms can also be an option to alleviate the sleepless woes.
Characteristics of Light vs. Heavy Sleepers
Which personality characteristics do light sleepers or heavy sleepers share?
We presented our survey participants with a series of statements and asked the extent to which they do or don’t identify with certain traits like perfectionism, worry, high stress levels, creativity, etc. We wondered if light sleepers share certain characteristics with other light sleepers, or if heavy sleepers share traits with fellow heavy sleepers.
After averaging the scores, we found a few interesting differences between heavy and light sleepers:
- Heavy sleepers are more likely to say they’re creative perfectionists who worry a lot, and that they’re easily annoyed and stressed-out.
- Light sleepers are more likely to describe themselves as happy and confident, and say they find it easy to make decisions.
- There appears to be almost no difference between light and heavy sleepers when it comes to how mentally alert they generally feel during waking hours. There’s also a very slight difference in their levels of confidence.
Overall, most of the average scores in this category varied by less than a point, which leads us to believe that although the groups might exhibit different personality characteristics, the variations cannot necessarily be attributed to whether someone is a light or a heavy sleeper.
Light vs. Heavy Sleepers:
How often do you remember your dreams?
When you wake up in the morning, is it easy to remember your dreams? Or are they gone as soon as you open your eyes? We asked our survey takers to tell us how well they remember their dreams.
Our survey results show that the number of heavy sleepers who often remember their dreams (50.3%) isn’t that much higher than heavy sleepers who don’t (49.7%). At the other end of the spectrum, the number of light sleepers who remember their dreams (62.4%) is significantly higher than those who don’t (37.6%).
So light sleepers are decidedly more likely to remember their dreams than heavy sleepers — but why is that, exactly?
According to a study conducted at the Lyon Neuroscience Research Center, dream recollection comes more naturally to lighter sleepers. The brains of those who easily recall their dreams have been shown to experience twice as many periods of wakefulness during sleep, allowing them to react more readily to sound and other stimuli during sleep. Hence, light sleepers stand a greater chance of dream recall. And because heavy sleepers perceive and react less to sound while they’re sleeping, they stay more fully asleep and don’t recall their dreams as easily.
What have you slept through?
The gift of being a heavy sleeper is that you can snore right through things that light sleepers cannot. We asked those who identified as heavy sleepers what kinds of experiences they could snooze through. Some results were expected; others definitely were not.
A majority of heavy-sleeping respondents reported that they’ve slept through common commotions like an alarm clock (60.2%) or a loud storm (55.4%). Construction noise or trash trucks were no detriment to sleep for 27.4% of them, as well. Less common occurrences that heavy sleepers have slept through are car accidents (4.3%), a child jumping on them (3.2%), and even being doused with water (1.4%).
As previously described, people with more frequent bursts of brain activity during sleep — the previously mentioned sleep spindles — can sleep through a lot more than those without. Sleep spindles only happen when brain waves are completely slowed down, and the more spindles a brain produces (as in heavy sleepers), the less reactive it is to external stimuli.
A few anecdotes from our survey respondents provide examples of how these heavy sleepers can snooze through instances that would wake up others:
- My child will sometimes come into my room in the middle of the night and wake up his dad, and they will have a conversation before he’s taken back to his own bed. I will have slept through it all. (35-year-old woman from San Francisco)
- I slept through the maintenance man knocking, then coming in and testing the fire alarm 2 days ago. I only knew he’d been in here because he told me later in the day. Yikes! (22-year-old man from Boston)
- The apartment across the street burned down and there were five fire trucks on the street, sirens blaring. I had my window open and everything, and I didn’t wake up ‘til the building was done for. (29-year-old man from St. Louis)
- A few months ago, someone shot out my glass patio door. My roommate had to shake me awake to get me up. He said it sounded like an explosion, but I did not flinch. (39-year-old man from San Francisco)
- Thirteen sticks of dynamite in the back yard to blow up a boulder so we could install an in-ground pool! I woke up and asked, “When are they going to blow up the rock?” I was told it was done while I was sleeping less than 100 feet away in my bedroom. (33-year-old woman from Philadelphia)
What wakes you up?
Other people can hear every breath and feel every shift or breeze around them, even when they’re asleep. We asked our light-sleeping respondents about the kinds of things that are most likely to wake them up.
The most common things that wake light sleepers are doors opening (36.2%), their partner snoring (35.8%), and footsteps (32.2%). Less common sources of disquiet include a fan (6.8%) or a dripping faucet (5.1%) — and a few respondents reported they’ve been awakened by someone turning the pages of a book (1.6%).
How is it that light sleepers can wake up so easily? Apparently, it’s the flipside of the same reason that heavy sleepers can sleep through hurricanes: People whose brains produce fewer sleep spindles throughout their night’s rest are lighter sleepers and don’t get as much Stage 3 “deep sleep” as heavy sleepers. Consequently, they react readily to external stimuli like sounds and sensations, often being awakened by them.
Here are some early-to-rise anecdotes from survey respondents who identify as light sleepers:
- Squirrels in the backyard climbing our trellis. (56-year-old woman from San Francisco-Oakland-San Jose)
- Someone turning on a light. (48-year-old woman from Houston)
- Smells wake me up. It can be body odor, smoke, food … Anything like that, and my eyes jolt awake. (27-year-old man from Miami-Ft. Lauderdale)
- A neighbor’s garage door opening. (23-year-old woman from St. Louis)
- Any sound associated with my child will wake me. (43-year-old woman from Dallas-Ft. Worth)
- Any noise that is unusual. An example would be something rustling outside, or footsteps when I should be alone in the house. (36-year-old man from Detroit)
- Motion detection lights in my backyard, because I live in an area with mountain lions, bears, deer, coyotes, raccoons, skunks, opossums. (49-year-old woman from Los Angeles)
- My partner grinding her teeth. (37-year-old man from Washington, D.C.)
Changes in Sleep Sensitivity
Changes in sleep patterns, plus common causes
Sometimes a person’s sleep sensitivity may change, and this can happen for any number of reasons. Changes in physical or mental health, new environmental triggers, a shift in a work or personal schedule, or many other factors can change a light sleeper into a heavy one, or vice versa.
When we asked our light-sleeping participants if their sleep sensitivity has changed over time, 26.6% said they used to be heavy sleepers. The other 73.4% responded that they’ve always been light sleepers. Of the heavy sleepers, 17.2% used to be light sleepers, and 82.8% have always slept heavily.
For the 330 survey takers who changed from heavy to light sleepers and the 185 who changed from light to heavy, we asked why they think their sleeping patterns were altered. The largest change occurred in 43.9% of heavy-to-light sleepers, who surmised that becoming a parent or caregiver changed their sleep. This is not surprising, given the estimate that parents can miss out about 350 hours of sleep during their baby’s first year.
Both groups — heavy-to-light and light-to-heavy sleepers — reported that factors such as a busier schedule, greater sleep deprivation, changes in the sleep environment, and the general effects of aging also played significant roles in changing the depth of their sleep.
There is still plenty of research to be completed on why certain people are light sleepers and others are heavy sleepers. Considering what’s known so far, it’s no surprise that no two sleepers are exactly alike, nor are the things that wake them (or don’t). Someone who can sleep through a helicopter chugging directly overhead may — or may not — have a completely different lifestyle from someone who’s awakened by a dog barking somewhere in the neighborhood. In addition to individual brain chemistry and structure, any number of lifestyle factors like parenthood, profession, geography, and overall health can contribute to the differences.
Continued study on sleep patterns, sleep spindles, sleep soundness, and related technologies will surely provide answers to the remaining mysteries of sleep. It could even offer couples more information on how to share a restful bed between heavy- or light-sleeping spouses, both achieving a good night’s sleep without one sacrificing their slumber for the other. Until the puzzles are solved, though, some of us will continue to wake at the drop of a pin while others slumber through the drop of an anvil.
Our survey was conducted online. It encompassed 2,712 U.S. residents, with at least 100 residents in each of 25 major cities across the United States. The cities were chosen based on population, media market size, and geographic location. They were:
- Atlanta, GA
- Baltimore, MD
- Boston, MA
- Charlotte, NC
- Chicago, IL
- Cleveland-Akron, OH
- Dallas-Ft. Worth, TX
- Denver, CO
- Detroit, MI
- Houston, TX
- Indianapolis, IN
- Las Vegas, NV
- Los Angeles, CA
- Miami-Ft. Lauderdale, FL
- Minneapolis-St. Paul, MN
- Nashville, TN
- New Orleans, LA
- New York, NY
- Philadelphia, PA
- Phoenix, AZ
- Pittsburgh, PA
- San Francisco- Oakland-San Jose, CA
- Seattle-Tacoma, WA
- St. Louis, MO
- Washington, DC
Participants were 49.5% men and 50.5% women. Their ages ranged from 18 to 82, with a median of 34. The sample included 1,706 people who are married. For the analysis by profession, there was a median of 50 responses per career field. Professions with fewer than 10 responses were excluded.
The survey was based on self-reporting. Respondents who missed an “attention check” question were disqualified. The margin of error was ±1.882% with a confidence interval of 95% based on the total population of all adults in the target cities.
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