AUGUSTA, Ga. — Think those wild college years are when people get the least amount of sleep each night? Think again. A new study finds Americans actually see less shut eye at age 40 than they do at any other point in their lives.
Luckily, a team from the Medical College of Georgia says things do get better as people age, with Americans sleeping more after the age of 60. The study discovered a U-shaped curve in the nation’s sleep patterns, with younger children sleeping the most, before sleep starts to drop off between ages 10 and 50. Eventually, the pattern bottoms out around age 40, where Americans sleep for the fewest number of hours each night.
Despite sleeping less, researchers did find that sleep efficiency actually stabilizes between ages 30 and 60. The team examined sleep data on more than 11,000 people over the age of six participating in the National Health and Nutrition Examination Survey, or NHANES. Researchers collected the data between 2011 and 2014. The survey also marks the first time 24-hour accelerometer data has been available for a nationally representative sample of Americans.
Each person wore these tracking devices on their wrists for seven straight days. Although they don’t directly measure sleep time, the devices do keep track of movement, which provides researchers with an idea if someone is asleep or not.
“We confirmed previous findings based on subjective measurement,” says Dr. Shaoyong Su in a university release. “People think children and adolescents sleep later and we found this. And, during middle age people sleep less and our findings support that objectively.”
Our golden years really are golden
Study authors say the increased sleep time later in life likely reflects the tendency of many Americans to retire around age 60. Simply put, retirees don’t have to get up as early anymore. However, the investigators add that health problems during old age may also contribute to this.
As for younger, working adults, the study finds many are sleeping “efficiently” even if they’re not sleeping for very long. In fact, 85 percent of participants had good sleep efficiency — or the time you actually sleep versus the time you set aside to sleep each night.
“Traditionally people think sleep efficiency goes straight down with age, but we did find there is a stable period, from ages 30 to 60 years old, that you have quite stable sleep efficiency,” Dr. Xiaoling Wang says.
Who’s staying up late?
The team found women generally sleep longer than men throughout their lives, but they also tend to go to bed later at night — especially as they get older. Women also experience more interrupted sleep, particularly if they’re mothers. Even so, the average American woman sleeps four minutes longer than men do.
It may come as no surprise that young adults around age 20 have the latest clock time for sleep onset, or CTSO. Also not surprising, high schoolers had the biggest difference between their weekday and weekend CTSO.
It turns out that peak CTSO comes at around age 21, when young adults stay up until 11:30 p.m., on average. While that may be late enough, researchers note they actually thought it would be later. Additionally, researchers found one in four children between ages six and 13 had a CTSO close to 11 p.m. Once people start to exit these “party years,” the team says the curve measuring bedtime shifted the other way.
“You hit the years where you are raising children and you are working and then what happens around the time of retirement? Your whole schedule begins to change,” study co-author Dr. Vaughn McCall explains.
Once retirement hits, McCall adds, bedtimes start to get later again.
Not all Americans see the same amount of quality sleep
The study also revealed that Black American have some of the most troublesome sleep patterns. This includes going to bed later, sleeping less, and getting less efficient rest. For the first time, study authors found that Mexican Americans have the earliest sleep onset and slept the longest, but this did not equate to an efficient sleep.
“One thing we cannot overestimate is the impact of sleep,” Wang says. Without sufficient sleep, “you overuse your body.”
The researchers add that your ability to adjust to less sleep decreases with age. McCall says doctors need to listen to sleep complaints from patients, as they could be a sign of mental or physical health problems.
“I think what these sleep parameters mean in terms of people’s health is that if you are a physician or other provider and patients comes in with some kind of complaint about their sleep, you need to interpret what they tell you in light of their stage in life and what their likely sleep patterns are going to be.”
“I don’t look at our findings necessarily as a benchmark of perfect health,” McCall says. “I look at this as a benchmark of what is happening in America.”
The findings appear in the journal Scientific Reports.