Does Evolution Explain Why Our Sleep Habits Change With Age?

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Laugh all you want now about Grandma's 8 p.m. bedtime; after reading this, you might just want to thank her. One team of researchers report that older adults' earlier body clocks may have evolved to ensure that at least one person was always awake to watch over a family group. They published their findings in the Proceedings of the Royal Society B.

Scientists believe that many groups of social animals take turns sleeping and standing guard. This sentinel hypothesis, as it's known, is easiest to observe in a line of sleeping ducks; the last duck in a row literally sleeps with one eye open. But we didn't know whether this phenomenon extended to humans.

To find out, researchers collaborated with Hadza people of northwestern Tanzania. Many Hadza maintain a hunter-gatherer lifestyle, working and sleeping far from the noise and light pollution of the cities. The researchers recruited a group of 33 adults between the ages of 20 and 60 and gave each person an actigraphic (movement-tracking) wristband. For 20 nights, the actigraphs recorded participants' tossing and turning, their waking, and their stillness in sleep.

The big-picture results looked a lot like you might expect. Average bed- and wake-up times were around 10 p.m. and 7 a.m., respectively. But those were just the averages. Within even this small group, two familiar chronotypes emerged: the older early birds, who bedded down around 8 p.m. and woke by 6 a.m., and the younger night owls, who were up past 11 p.m. and slept until 8 a.m.

Most compellingly, the researchers say, nobody ever slept through the night. Each person woke several times per sleep period, whether to pee, go for a smoke, soothe a crying baby, or just roll over in bed. The resulting gaps in sleep time meant that someone in the group was awake at almost all times. Out of 20 nights, there were only 18 minutes in which the entire group was sound asleep.

Co-author Charlie Nunn is an evolutionary anthropologist at Duke University. He says the group's early bird/night owl split, combined with the frequent mid-sleep awakenings, may be our bodies' way of keeping our families safe.

"If you're in a lighter stage of sleep, you'd be more attuned to any kind of threat in the environment," he said in a statement.

Nunn and his colleagues suggest that the staggered sleeping shifts are not an accident but an adaptation.

"A lot of older people go to doctors complaining that they wake up early and can't get back to sleep," Nunn said. "But maybe there's nothing wrong with them. Maybe some of the medical issues we have today could be explained not as disorders, but as a relic of an evolutionary past in which they were beneficial.”

Maybe. Maybe not. It's quite possible that older adults' sleep issues are just that: issues, and signs of an aging body. We'll need a lot more research on the subject before we can say for sure. In the meantime, let's cut Grandma some slack. Evolutionary advantage or no, we all just want to sleep.

11 Things You Might Not Know About Neil Armstrong

NASA/Hulton Archive/Getty Images
NASA/Hulton Archive/Getty Images

No matter where private or government space travel may take us in the future, NASA astronaut Neil Armstrong (1930-2012) will forever have a place as the first human to ever set foot on solid ground outside of our atmosphere. Taking “one small step” onto the Moon on July 20, 1969, he inspired generations of ambitious people to reach for the stars in their own lives. On the 50th anniversary of Apollo 11, we're taking a look back at the life of this American hero.

1. Neil Armstrong knew how to fly before he got a driver's license.

Neil Armstrong poses for a portrait 10 years before the 1969 Apollo mission
NASA/Hulton Archive/Getty Images

Born August 5, 1930 in Wapakoneta, Ohio, Armstrong became preoccupied with aviation early on. At around age 6, his father took him on a ride in a Ford Trimotor airplane, one of the most popular airplanes in the world. By age 15, he had accumulated enough flying lessons to command a cockpit, reportedly before he ever earned his driver’s license. During the Korean War, Armstrong flew 78 combat missions before moving on to the National Advisory Committee for Aeronautics (NACA), the precursor to NASA.

2. Neil Armstrong's famous quote was misheard back on Earth.

When Armstrong and Buzz Aldrin touched down on the Moon, hundreds of millions of television viewers were riveted. Armstrong could be heard saying, “That’s one small step for man, one giant leap for mankind.” But that’s not exactly what he said. According to the astronaut, he was fairly sure he stated, “That’s one small step for a man, one giant leap for mankind.” The “a” may have broken up on transmission or it may have been obscured as a result of his speaking patterns. (According to First Man: The Life of Neil A. Armstrong, Armstrong said, “I’m not particularly articulate. Perhaps it was a suppressed sound that didn’t get picked up by the voice mike. As I have listened to it, it doesn’t sound like there was time for the word to be there. On the other hand, I think that reasonable people will realize that I didn’t intentionally make an inane statement, and certainly the ‘a’ was intended, because that’s the only way the statement makes any sense. So I would hope that history would grant me leeway for dropping the syllable and understand that it was certainly intended, even if it wasn’t said—although it actually might have been.”) Armstrong claimed the statement was spontaneous, but his brother and others have claimed he had written it down prior to the mission.

3. We don't have a really good picture of Neil Armstrong on the Moon.

Buzz Aldrin is seen walking on the moon
NASA/Hulton Archive/Getty Images

One of the most celebrated human achievements of the 20th century came at a time when video and still cameras were readily available—yet there are precious few images of Armstrong actually walking on the surface of the Moon. (One of the most iconic shots, above, is Aldrin; Armstrong only appears as a reflection in his helmet.) The reason, according to Armstrong, is that he really didn’t care and didn’t think to ask Aldrin to snap some photos. “I don't think Buzz had any reason to take my picture, and it never occurred to me that he should,” Armstrong told his biographer, James R. Hansen. “I have always said that Buzz was the far more photogenic of the crew."

4. A door hinge may have made all the difference to the Apollo 11 mission.

Theories abound as to why it was Armstrong and not Buzz Aldrin who first set foot on the Moon. (On the Gemini missions, the co-pilot did the spacewalks, while the commander stayed in the craft. For Apollo 11, Armstrong was the commander.) The answer may have been the simple logistics of getting out of their lunar module. The exit had a right hinge that opened inwardly, with the man sitting on the left (Armstrong) having the most unobstructed path to the outside. Aldrin would have essentially had to climb over Armstrong to get out first.

5. Neil Armstrong was more concerned about landing on the Moon than he was walking on it.

The lunar module that took NASA astronauts to the moon
NASA/Hulton Archive/Getty Images

The romantic notion of a human stepping foot on space soil captured imaginations, but for Armstrong, it was getting there in one piece that was the real accomplishment. The lunar module Armstrong controlled had to be brought down on the Moon’s surface from 50,000 feet up, avoiding rocks, craters, and other obstacles as it jockeyed into a position for landing. Because there is no air resistance, nothing could slow their descent, and they used thrusters to guide the craft down. That meant there was only enough fuel to attempt it once. The “business” of getting down the ladder was, in Armstrong’s view, less significant.

6. Neil Armstrong was carrying a bag worth $1.8 million.

When Armstrong surveyed the surface of the Moon, he collected a bag of dust for NASA scientists to examine. Apollo moon samples are illegal to buy or sell, but that apparently wasn't the case with the “lunar collection bag” Armstrong used to hold the samples. In 2015, the bag was purchased by Chicago resident Nancy Lee Carlson from a government auction site for $995. But its sale was, apparently, an accident: When Carlson sent the bag to NASA to confirm its authenticity, NASA said it was their property and refused to send it back—so Carlson took the agency to court. A judge ruled it belonged to Carlson, and in 2017, she sold the bag for a whopping $1.8 million at a Sotheby’s auction.

7. Neil Armstrong and his fellow Apollo 11 astronauts had to spend three weeks in quarantine.

Richard Nixon greets the returning Apollo 11 astronauts
NASA/Hulton Archive/Getty Images

When Armstrong, Aldrin, and Michael Collins (who remained behind in the command module while the other two touched down on the Moon) returned to Earth and were fetched by the USS Hornet, they got a king’s welcome. The only asterisk: They had to bask in their newfound fame from inside a sealed chamber. All three men were quarantined for three weeks in the event they had picked up any strange space virus. When President Richard Nixon visited, he greeted them through the chamber’s glass window.

8. Neil Armstrong's space suit was made by Playtex.

Yes, the undergarment people. In the early 1960s, NASA doled out contract work for their space suits to government suppliers, but it was Playtex (or more properly the International Latex Corporation) and their understanding of fabrics and seams that led to NASA awarding them responsibility for the Apollo mission suits. Their A7L suit was what Armstrong wore to insulate himself against the harsh void of space when he made his famous touchdown. The astronaut called it “reliable” and even “cuddly.”

9. Neil Armstrong became a university professor.

Newil Armstrong sits behind a desk in 1970
AFP/Getty Images

Following his retirement from NASA in 1971, Armstrong was reticent to remain in the public eye. Demands for his time were everywhere, and he had little ambition to become a walking oral history of his singular achievement. Instead, he accepted a job as a professor of engineering at the University of Cincinnati and remained on the faculty for eight years.

10. Neil Armstrong once sued Hallmark.

Hallmark was forced to defend itself when Armstrong took issue with the company using his name and likeness without permission for a 1994 Christmas ornament. The bulb depicted Armstrong and came with a sound chip that said phrases like, “The Eagle has landed.” The two parties came to an undisclosed but “substantial” settlement in 1995, which was, according to First Man, donated to Purdue University (minus legal fees).

11. Neil Armstrong was a Chrysler pitchman.

Armstrong’s preference to lead a private life continued over the decades, but he did make one notable exception. For a 1979 Super Bowl commercial spot, Armstrong agreed to appear on camera endorsing Chrysler automobiles. Armstrong said he did it because he wanted the struggling U.S. car maker to improve their sales and continue contributing to the domestic economy. The ads never mentioned Armstrong was an astronaut.

Pioneering Heart Surgeon René Favaloro Is Being Honored With a Google Doodle

Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
The Cleveland Clinic Center for Medical Art & Photography, Wikimedia Commons // CC BY 4.0

Argentinian heart surgeon René Favaloro is the subject of today’s Google Doodle, which features a sketched portrait of the doctor along with an anatomical heart and several medical tools, The Independent reports.

The renowned doctor was born on this day in 1923 in La Plata, the capital of Argentina’s Buenos Aires province, and pursued a degree in medicine at La Plata University. After 12 years as a doctor in La Pampa, where he established the area’s first mobile blood bank, trained nurses, and built his own operating room, Favaloro relocated to the U.S. to specialize in thoracic surgery at the Cleveland Clinic.

In 1967, Favaloro performed coronary bypass surgery on a 51-year-old woman whose right coronary artery was blocked, restricting blood flow to her heart. Coronary bypass surgery involves taking a healthy vein from elsewhere in the body (in this case, Favaloro borrowed from the patient’s leg, but you can also use a vein from the arm or chest), and using it to channel the blood from the artery to the heart, bypassing the blockage. According to the Mayo Clinic, it doesn’t cure whatever heart disease that caused the blocked artery, but it can relieve symptoms like chest pain and shortness of breath, and it gives patients time to make other lifestyle changes to further manage their disease.

Favaloro wasn’t keen on being called the “father” of coronary bypass surgery, but his work brought the procedure to the forefront of the clinical field. He moved back to Argentina in 1971 and launched the Favaloro Foundation to train surgeons and treat a variety of patients from diverse economic backgrounds.

Favaloro died by suicide on July 29, 2000, at the age of 77, by a gunshot wound to the chest. His wife had died several years prior, and his foundation had fallen deeply into debt, which Argentinian hospitals and medical centers declined to help pay, The New York Times reported at the time.

“As a surgeon, Dr. Favaloro will be remembered for his ingenuity and imagination,” his colleague Dr. Denton A. Cooley wrote in a tribute shortly after Favaloro’s death. “But as a man ... he will be remembered for his compassion and selflessness.” Today would have been his 96th birthday.

[h/t The Independent]

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