Science & technology | Well Informed Is too much sleep as bad as too little? The quest for the optimal amount of shut-eye July 2nd 2026 “EIGHT HOURS labour, eight hours recreation, eight hours rest,” said Robert Owen, a Welsh textile-maker, in 1817. His aim was a fairer work week, but the idea that sleeping eight hours a night is best has since become the received wisdom. Is it right? Not getting enough kip can certainly be a problem. A bad night’s sleep can lead to a drop in cognitive abilities, increased stress and general grumpiness the following day. Chronic sleep deprivation is associated with cognitive decline, psychiatric disorders and even an early death. But too much sleep may also be bad for you. The evidence suggests a U-shaped relationship between health and sleep duration, with both insufficient and excessive slumber being worse than an optimal middle range.
In 2015 two big studies tried to work out exactly where that range lies. The first, published in Sleep Health, assessed 575 studies published between 2004 and 2014. For those aged 18-64, the recommended amount was between seven and nine hours a night, but that fell to just seven or eight hours for those over 65. The second, published in Sleep, analysed 311 studies. It concluded that around seven hours of shut-eye was the best target, but noted uncertainty about the negative effects of regularly sleeping longer than nine hours. A more recent study, published in Nature on May 13th, refined these estimates by studying the effects of sleep duration on specific parts of the body. Its authors used the idea of “biological clocks”, which try to work out whether a person’s physiology is in better or worse nick than their chronological age would suggest. The researchers applied the concept to individual organs. Someone with a brain pathology, for example, might have a “brain age” that is higher than their actual age, explains Junhao Wen, a computational neuroscientist at Columbia University and self-admitted light sleeper, who led the study. Someone sporty might have muscles that look younger than their years. Dr Wen and his team tracked the relationship between sleep duration and 23 different biological clocks across 500,000 adults (much of the data came from the UK BioBank, a big database). They found the U-shaped pattern across nine body systems, including the brain, lungs, liver and skin. Their findings suggest that the optimal amount of sleep is 6.5-7.8 hours for women and 6.4-7.7 hours for men. Those struggling to get a full night’s rest should not despair. Applying population-level results to individual lives is tricky, for one thing. For another, disentangling cause and effect is not easy. Are some organs prematurely aged because their owners sleep too little? Or is some other factor causing both the ageing and the lack of sleep? Besides, says Michael Grandner, a psychiatrist at the University of Arizona, duration is just one measure. Quality, regularity and continuity of sleep matter, too. His advice is: “Don’t freak out about any particular number, unless it’s a very unusual number.”
That looks like sage advice. One irony of sleep is that worrying about it can make things worse. A 2025 survey from the American Academy of Sleep Medicine found that 76% of respondents had lost sleep due to worries about sleep. Dr Wen advises listening to what your body is telling you, and getting enough that you feel refreshed when you wake up. Aim for six to eight hours a night, in other words, but don’t toss and turn over the precise number. ■ After a free, evidence-based guide to health and wellness? Sign up to our weekly Well Informed newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/06/26/is-too-much-sleep-as- bad-as-too-little
Route 66: How a century-old highway helps explain America A Danish bestseller about butterflies has set hearts aflutter Heinz tomato ketchup and the sweet taste of market dominance Amorality and greed at Silicon Valley’s favourite university The Herculaneum scrolls are starting to be read Messi, Mbappé, Ronaldo: this World Cup belongs to the superstars
Route 66: How a century-old highway helps explain America Driving from Chicago to Santa Monica you glimpse the best aspects of the country July 2nd 2026 The “Mother Road” was what John Steinbeck called it in “The Grapes of Wrath”; the Joads drove west from Oklahoma in search of a better life in California. Nat King Cole sang that it was where you “get your kicks”. It gave its name to a popular network TV show in the 1960s and inspired the plot and setting of Pixar’s “Cars”, an animated film from 2006. It is the path of one of America’s most popular road trips.
Route 66 became the most famous highway in the world partly due to good timing. Its heyday coincided with America’s cultural and geopolitical rise and the emergence of car culture. This year the route turns 100. And though the modern interstate is more efficient, it is far less colourful. America is turning 250 in a divided, uneasy time. The best antidote for the birthday blues is to drive all 2,400 miles (3,860km), from Chicago to Santa Monica, on the Mother Road. Though it began as a motley stitching of state and local roads—not until 12 years after its inauguration did it become the first fully paved American highway—it quickly became the main route west, passing through eight states. Farmhands used it to flee the Dust Bowl; so did workers, many of them African-Americans from Texas and Oklahoma, who flocked to California’s booming industrial base after the second world war; merry holidaymakers travelled along it to Los Angeles. During Route 66’s early years, more people got behind the wheel, thanks to Henry Ford’s affordable Model T. Services for drivers flourished, including petrol stations, diners and motels, as did the small towns through which the route passed. But with just a single lane in each direction, the popular route turned into a car park. Dwight Eisenhower, America’s president, had been impressed by Germany’s autobahn while serving in Europe during the second world war.
In 1956 he signed the Federal Aid Highway Act to fund a system of multi- lane interstate highways. In the subsequent decades some new highways paralleled Route 66; others simply built over it. As a federal highway it was decommissioned in 1985. That could have been the end of the story. But grassroots organisations formed to preserve and protect Route 66, in line with the observation of
Alexis de Tocqueville from nearly two centuries ago: “Americans…are forever forming associations…at the head of any new undertaking.” That is the first lesson from Route 66: for all the hands wrung and pixels blazed about the social atomisation wreaked by the digital age, Americans retain their heartening passion for in-person voluntarism. All eight states have volunteer-led groups devoted to preserving and promoting Route 66. Cheerful, garrulous volunteers staff small-town museums and roadside attractions; indeed, the route’s vibrancy largely stems from the efforts of countless people who decided, each for their own reasons, that they want it to remain delightful and not fade into disuse and obscurity. Bill Thomas, who chairs a national preservation group, the Route 66 Road Ahead Partnership, and is the head of economic development for Logan County, Oklahoma, sees preserving the route as a means to attract tourists. Atlanta, Illinois, a town of just 1,600 residents, claims 8,000 visitors per year. Atlanta’s main attraction is the weird, wonderful American Giants Museum, devoted to enormous fibreglass statues that businesses used to draw customers’ eyeballs and wallets. (Their unfortunate tendency to fall over sparked lawsuits and prompted their retirement.) The museum is an old Texaco petrol station; across the street, a fibreglass giant offers (or is preparing to club passers-by to death with) a hot dog the size of a park bench. Such roadside oddities abound along the route. There is a motel of painted concrete tepees in Holbrook, Arizona. A little farther down the road is an abandoned mining town reinvented as an open-air museum of the Old West. There are also motorcycle museums, run by lovers of the open road who want to share their passion with the public. Collectively these attractions provide the second lesson: America’s economy is dynamic and productive, yes, but also intensely creative. American businesses are very good at making customers want to buy things. Advertising, done well, is an art. Though today it is often the province of big, expensive agencies, Route 66 contains hundreds of reminders that it can also be an individual endeavour, requiring little more than a few cans of paint and a memorable name (such as the Blue Swallow and the Wagon Wheel, both motels). Gimmicks work, too: if you finish a 72-ounce steak at
the Big Texan Steak Ranch in Amarillo within an hour and without vomiting, your meal is free. The final lesson is more of a reminder: that mobility helped America boom. People can move to a new city or state to find better opportunities and reinvent themselves. Yet fewer are doing so today. And politicians have grown suspicious of newcomers. The left hates the arrival of new middle- class Americans and wails about gentrification. The right hates the arrival of