Health: quotes, facts and reflections - Page 6

Related subjects

Browse this subject and connected topics.

Keep reading below, or choose a related topic to explore something different.

DriveReading mode

StillnessReading mode

WonderReading mode

DriveArt

Cataracts clouded Claude Monet's vision in his seventies and changed the way he saw colour. He kept working on his water lilies, had surgery in 1923 and returned to painting a few months later.

A cataract is a clouding of the lens inside the eye. Monet's first signs appeared around 1912, and as his lenses yellowed, reds and browns came to dominate his canvases while blues faded. By 1922 he could barely see and spoke of giving up. His friend Georges Clemenceau, the former French prime minister, urged him to have the operation, and in 1923 surgeons removed the lens of his right eye. Afterwards he saw everything with a strong blue tint for a time and needed special tinted glasses. He went back to the great Water Lilies panels, which were still in his studio when he died in December 1926. They were installed at the Musée de l'Orangerie in Paris in May 1927.

Art historyRead card

DriveLiterature

John Milton, completely blind by 1652, composed Paradise Lost in his head and dictated it to whoever would write it down. He had served the English republic, and when the monarchy returned in 1660 he was briefly jailed and lucky to escape worse.

Milton had been the republic's Secretary for Foreign Tongues, writing its official letters in Latin, and had publicly defended the execution of Charles I. After the Restoration of 1660 he went into hiding, two of his books were publicly burned and he spent some weeks in prison before friends secured his release. He composed the epic in the years that followed, holding long passages in his memory overnight; an early account has him complaining in the morning that he wanted to be 'milked' by whoever came to write. The poem runs to more than ten thousand lines of blank verse, unrhymed but with a steady rhythm, and appeared in 1667. He sold it for £5, with £5 more once 1,300 copies had sold. Its famous line about the mind making 'a Heav'n of Hell' is spoken by Satan.

Literary historyRead card

WonderMind

Placebo pills can ease symptoms even when patients know they are dummies. In trials for irritable bowel syndrome and chronic low back pain, people who knowingly took pills with no active drug reported feeling better; this is called open-label placebo.

Placebo effects were long thought to depend on deception: patients had to believe a pill was a real drug. Ted Kaptchuk, who directs a placebo research programme at Harvard Medical School, tested this in 2010 with 80 patients with irritable bowel syndrome. One group was told plainly that their pills contained no medicine, yet they reported more relief than a group given no pills. A 2016 trial in Portugal, on which he also worked, found similar results for chronic low back pain. Nobody is sure why: the ritual of taking a pill, the attention of clinicians and a lifetime of learned expectations may all play a part. The effect is on how symptoms feel; there is no evidence that dummy pills cure infections, tumours or other diseases.

Harvard Medical SchoolRead card

StillnessMind

Time in nature may help tired attention recover. Attention restoration theory holds that hours of deliberate focus wear attention down, while clouds, leaves or moving water hold it gently and give it a chance to rest.

The psychologists Rachel and Stephen Kaplan set out the theory in their 1989 book The Experience of Nature. They distinguished 'directed attention', the effortful focus used to stay on a task and shut out distractions, from 'soft fascination', the easy interest that clouds, leaves or moving water hold without any effort. In their view directed attention is a limited resource that runs down through the day, and time in a softly fascinating place lets it recover. In a 2008 University of Michigan study, people did better on a memory test after walking through an arboretum than after walking along city streets. Other studies have found similar gains, though effect sizes and methods vary and not every result has been repeated.

Attention restoration theoryRead card

DriveHealth

Working muscles do more than move you: when they contract, they release chemical messengers called myokines that travel in the blood and act on other organs. In that sense, muscle is also a hormone-producing organ.

The Danish physiologist Bente Klarlund Pedersen and colleagues proposed the name 'myokines' in 2003 for signalling molecules released by muscle. One of the first identified was interleukin-6, which can rise up to a hundredfold in the blood during long exercise. In other settings it is linked with inflammation, but released from working muscle it appears to have mainly anti-inflammatory effects. Myokines are one route by which physical activity affects metabolism, inflammation, fat tissue, bone and the brain, which helps explain some of exercise's wide health benefits. Which molecules are released, and what they do, depends on the kind and intensity of activity, so the idea is broader than a single 'exercise hormone'.

Exercise physiologyRead card

StillnessHealth

Caffeine keeps you awake by blocking a sleep signal, not by removing it. A substance called adenosine builds up in the brain while you are awake and makes you drowsy; caffeine occupies its receptors for a few hours, but the adenosine is still there.

Adenosine is a by-product of the energy cells use, and it gradually accumulates in the brain during waking hours, damping the activity of nerve cells that keep you alert. In the two-process model of sleep, proposed by Alexander Borbély in 1982, this growing sleep pressure is called 'process S', and it works together with the body's circadian clock, its roughly 24-hour internal rhythm. Caffeine's shape is close enough to adenosine's that it can occupy the same receptors without activating them, so it dulls sleepiness without reducing the need for sleep. Its half-life in adults, the time the body takes to clear half of it, is often around five hours but varies widely. When it wears off, the adenosine that kept building can act again, one reason for the slump some people call a caffeine crash.

Sleep scienceRead card

StillnessHealth

Shinrin-yoku, or 'forest bathing', is the Japanese practice of spending slow, unhurried time among trees. Japan's Forestry Agency coined the term in 1982 to encourage people to visit forests for their health.

The term was coined by Tomohide Akiyama, then director-general of the Forestry Agency, at a time when Japan was urbanising fast; that year the agency held a forest recreation event in Nagano prefecture. It began as a public campaign rather than a scientific claim, but it drew researchers' attention. Some, including Qing Li at Nippon Medical School in Tokyo, reported short-term changes after forest visits in mood, blood pressure and immune markers such as the activity of natural killer cells, white blood cells that attack infected cells. Li tentatively linked these to phytoncides, aromatic compounds that trees release into the air. Many of these studies are small, though, and struggle to separate the effect of trees from walking, cleaner air, quiet or simple expectation.

Japanese public healthRead card

StillnessHealth

People with weak social ties die earlier on average. A 2010 analysis of 148 studies found that those with stronger relationships were about 50% more likely to be alive at the end of the studies than those with weaker ones.

The 2010 meta-analysis, led by the psychologist Julianne Holt-Lunstad, pooled data on more than 300,000 people followed for an average of about seven and a half years; a meta-analysis combines many studies to reach a more reliable answer. In 2023 the U.S. Surgeon General, the country's leading public health official, issued an advisory on loneliness that reviewed this and later research. It concluded that social disconnection carries a mortality risk comparable to smoking up to 15 cigarettes a day. These are patterns across large populations, not a prediction for any one person. The advisory also describes likely pathways: long-term stress hormones, inflammation, poorer sleep and fewer healthy habits such as exercise or seeing a doctor.

Public health researchRead card

DriveHealth

Muscle mass and strength slowly decline with age, a process doctors call sarcopenia. Strength training and a diet with enough protein can markedly slow the loss, and even people in their nineties can still grow stronger.

The word comes from the Greek sarx, flesh, and penia, poverty or loss. The nutrition researcher Irwin Rosenberg proposed it in 1989, arguing that no change of ageing was more dramatic or mattered more for independence than the loss of lean body mass. One review puts the loss of muscle mass at roughly 3 to 8% per decade after the age of 30, faster after 60, though rates vary widely by person and by how muscle is measured. The loss is not fixed: in a 1990 study at a Boston nursing home, nine frail residents aged about 90 increased their leg strength by an average of 174% after eight weeks of weight training, and walked faster too.

Geriatric medicineRead card

DriveHealth

Aerobic exercise such as brisk walking, running or cycling can raise levels of BDNF, a protein that helps brain cells survive and form and strengthen connections with each other.

BDNF stands for brain-derived neurotrophic factor. It is made in the brain and elsewhere in the body, and it supports the survival of nerve cells and the growth and strengthening of the connections between them, part of the brain's capacity to change that scientists call plasticity. A 2015 meta-analysis by Kristen Szuhany and colleagues, pooling 29 studies with about 1,100 participants, found that a single session of exercise raised BDNF in the blood by a moderate amount, and that regular exercise made that rise larger. Regular activity is also linked with modest gains on some memory and planning tests, but how large they are, and how much BDNF drives them, varies between studies. BDNF is one plausible link between exercise and a healthier brain, not the whole explanation.

NeuroscienceRead card

WonderHealth

Bone is living tissue, rebuilt throughout life. Cells called osteoclasts dissolve small patches of old bone and cells called osteoblasts fill them with new bone, renewing roughly a tenth of an adult skeleton each year.

In the first year of life almost the entire skeleton is replaced; in adults the turnover slows to about 10% a year. This constant remodelling repairs tiny cracks from everyday stress, stores or releases calcium and phosphate as the body needs them, and responds to load, which is why bones that bear more weight stay denser. The balance matters: when breakdown outpaces building, as often happens after menopause, bones thin and osteoporosis can follow. Astronauts in weightlessness lose bone quickly because their skeletons carry no load. Different bones and regions renew at different rates, so the popular claim that you get a 'new skeleton every ten years' is too neat: some bone is renewed quickly, while other parts last for decades.

Human biologyRead card

WonderHealth

Teenagers' body clocks really do run later. During adolescence the times people naturally fall asleep and wake up shift later, peaking around the age of 20, then drift earlier through adulthood. This personal timing, called chronotype, is shaped by both genes and age.

The age pattern comes from a 2004 survey of about 25,000 people in Central Europe led by the chronobiologist Till Roenneberg, which found that people are at their latest around 20; the researchers suggested this turning point could mark the biological end of adolescence. Chronotype is often measured with the Morningness-Eveningness Questionnaire, devised by James Horne and Olov Östberg in 1976. Genes matter too: a 2016 study of 128,266 people led by Samuel Jones found 16 genetic regions linked to being a morning person, some near known body-clock genes, and a 2019 study of nearly 700,000 people raised the count to 351. Light, school and work hours also shape sleep, which is why school-start-time research treats early timetables as a biological as well as a social issue.

Circadian researchRead card

DriveScience

Katalin Karikó spent decades researching mRNA, the molecule that carries a cell's instructions for making proteins, despite repeated grant rejections and a demotion. Her work with Drew Weissman on modified mRNA paved the way for the mRNA vaccines at the heart of the COVID-19 response.

Karikó moved from Hungary to the United States in 1985 and spent years at the University of Pennsylvania trying to win funding for mRNA work that few colleagues believed in. In 1995 she was demoted, and she later described being pushed out of posts more than once. The obstacle was that mRNA made in the laboratory set off a strong inflammatory reaction from the immune system. In 2005 she and Drew Weissman showed that replacing one of RNA's building blocks, uridine, with a slightly altered form such as pseudouridine largely avoided that reaction. The mRNA vaccines rest on the same principle, and the pair shared the 2023 Nobel Prize in Physiology or Medicine.

Nobel PrizeRead card

DriveHealth

In 1984 Australian doctor Barry Marshall drank a culture of Helicobacter pylori bacteria and within days developed gastritis, an inflamed stomach lining. He and pathologist Robin Warren had argued that this bacterium, not stress, lies behind most stomach ulcers.

At the time most doctors believed ulcers came from stress, spicy food and excess stomach acid, and that no bacterium could survive in the acidic stomach. Warren, working in Perth, had been seeing spiral-shaped bacteria in inflamed stomach tissue since 1979; Marshall joined him and managed to grow them in the laboratory. When they could not infect animals, Marshall infected himself, and a biopsy confirmed the bacteria had taken hold. Later clinical trials showed that H. pylori is behind most peptic ulcers, sores in the stomach or the first part of the small intestine, and that antibiotics can cure them for good, whereas acid-reducing drugs only healed them for a while. Marshall and Warren shared the 2005 Nobel Prize in Physiology or Medicine.

Nobel PrizeRead card

DriveHealth

Chinese scientist Tu Youyou discovered artemisinin, now one of the most effective malaria drugs. Her team had screened hundreds of traditional remedies; a fourth-century medical text led her to extract sweet wormwood without high heat, which kept the active compound intact.

Tu worked for Project 523, a secret Chinese military programme launched in 1967 to find new malaria treatments, partly to help North Vietnamese soldiers suffering from drug-resistant malaria. Her team gathered some 2,000 traditional recipes and tested hundreds of plant extracts. Sweet wormwood (Artemisia annua) showed promise but gave inconsistent results. In a handbook of emergency remedies by the fourth-century writer Ge Hong, Tu found an instruction to soak the herb in water and drink its juice, with no boiling, and suspected that heat was destroying the active ingredient. A low-temperature extraction using ether worked in 1971. She shared the 2015 Nobel Prize in Physiology or Medicine for the discovery.

Nobel PrizeRead card

DriveHealth

Frederick Banting, Charles Best and James Collip, the three men named on the U.S. insulin patent granted in January 1923, signed their rights over to the University of Toronto for one dollar each. The university then licensed drug companies to make insulin while keeping control over its quality.

Before insulin, type 1 diabetes, in which the pancreas stops making the hormone that controls blood sugar, usually killed children within a year or two of diagnosis. Banting, a surgeon, had the original idea in 1920; Best, a student, helped him run the experiments in J. J. R. Macleod's Toronto laboratory; Collip, a biochemist, found how to purify the extract enough to treat patients safely, and the first successful treatment followed in January 1922. The 1923 Nobel Prize went to Banting and Macleod, who shared their prize money with Best and Collip. Banting is often quoted as saying insulin ‘belongs to the world’, but no reliable source for the remark has been found; the one-dollar assignment is on record.

Banting HouseRead card

DriveHealth

When Jonas Salk was asked on television who owned the patent on his polio vaccine, he said there was no patent, that it belonged to the people, and asked, ‘Could you patent the sun?’ Polio had been paralysing tens of thousands of children a year.

The exchange was with the broadcaster Edward R. Murrow on 12 April 1955, the day results from a nationwide field trial showed the vaccine was safe and effective. Salk's vaccine used a killed, inactivated form of the poliovirus, unlike the oral vaccine with live, weakened virus that Albert Sabin developed later. Lawyers for the vaccine's funder, the National Foundation for Infantile Paralysis, known as the March of Dimes, had already looked into a patent and concluded that it would probably fail, because the vaccine relied on methods other scientists had already published. Polio cases have since fallen by more than 99% worldwide. Salk spent his last years working, without success, on a vaccine against HIV.

Medical historyRead card

DriveArt

On 17 September 1925, a streetcar hit the bus carrying eighteen-year-old Frida Kahlo, breaking her spine, pelvis and right leg. She had planned to study medicine; instead, confined to bed for months, she began painting with a mirror fixed above her and an easel made for lying down.

Her mother had the mirror fitted to the top of her four-poster bed and an easel made that she could use lying down, and the self-portraits Kahlo began there became central to her work. She gave a plain reason for painting herself so often: she was often alone, and she was the subject she knew best. Her injuries never fully healed; she went through around thirty operations and long spells in bed over her life. She married the muralist Diego Rivera in 1929, divorced him in 1939 and remarried him in 1940. Alongside still lifes, portraits and work on Mexican politics and identity, her own face became one of the best-known in twentieth-century art.

Art historyRead card

DriveMusic

In 1802, realising he was going deaf, Ludwig van Beethoven wrote a private letter to his brothers, now called the Heiligenstadt Testament. In it he described despair, isolation and thoughts of death, and wrote that only his art had held him back from ending his life.

Beethoven wrote it in October 1802 in Heiligenstadt, then a village outside Vienna, where his doctor had sent him to rest his hearing. It is called a testament because it reads partly like a will, but he never sent it; it was found among his papers after his death in 1827. He described the shame of hiding his deafness from others and his resolve to live on because he felt he still had music to write. He lived another twenty-five years and composed many of his greatest works as his hearing failed, including the Ninth Symphony. At its 1824 premiere, according to accounts, a singer turned him round to see the applause he could not hear.

Music historyRead card

DriveMind

The popular claim that a habit takes 21 days to form has no research behind it. In a well-known London study, a new daily behaviour took 66 days on average to become automatic, and anywhere from 18 to 254 days depending on the person and the habit.

The 21-day idea seems to go back to the plastic surgeon Maxwell Maltz, who wrote in his 1960 book Psycho-Cybernetics that patients took at least about three weeks to get used to a new face. In the 2010 study, Phillippa Lally and colleagues at University College London asked 96 volunteers to pick one daily habit, such as eating a piece of fruit with lunch or running before dinner, and to rate each day how automatic it felt. Over twelve weeks the feeling rose quickly at first and then levelled off; the longest times were projected beyond the study's end. Missing a single day did not derail the process. The lesson is how much people vary, not a new '66-day rule'.

University of SurreyRead card

DriveMind

A well-tested treatment for depression, called behavioural activation, helps people return step by step to meaningful or rewarding activities, instead of waiting for motivation or mood to improve first.

Depression often sets up a loop: low mood leads people to do less, and doing less cuts them off from the small rewards that used to lift their mood, which psychologists call reinforcement. Behavioural activation breaks the loop from the action side. With a therapist, people note what they have stopped doing, schedule small, manageable activities, then record how they actually felt. The approach grew from Peter Lewinsohn's work in the 1970s and was sharpened by Neil Jacobson's team in the 1990s. In a large UK trial published in 2016, behavioural activation delivered by junior mental health workers worked as well as cognitive behavioural therapy delivered by experienced therapists, at lower cost. It is a structured treatment, not a general rule that motivation always follows action.

Clinical psychologyRead card

StillnessMind

Self-compassion means treating yourself kindly when you struggle or fail, without contempt but also without denying the mistake or your responsibility. Research generally links it with better psychological wellbeing and, in some studies, greater willingness to try again after failure.

The psychologist Kristin Neff, who defined the idea for research in 2003, describes three parts: kindness towards yourself instead of harsh judgement; remembering that struggling is part of being human, not a personal defect; and noticing painful feelings without ignoring them or being swept away by them. Unlike self-esteem, which depends on doing well, self-compassion is about how you treat yourself when you have not. In a 2012 study by Juliana Breines and Serena Chen, students who were encouraged to take a self-compassionate view after failing a hard vocabulary test studied longer for a retest than those given a self-esteem boost. Such findings challenge the idea that harshness is needed to take responsibility.

Psychology researchRead card

StillnessMind

REM sleep, the stage of sleep with the most vivid dreams, may help take the sting out of upsetting memories. A leading hypothesis holds that the brain replays them while the stress chemical noradrenaline is almost switched off, softening the emotion without erasing the memory.

Matthew Walker and Els van der Helm set out the idea in 2009 under the name 'sleep to forget, sleep to remember': sleep keeps the content of an emotional memory but softens its feeling. REM stands for rapid eye movement, because the eyes dart about under closed lids in this stage. In a 2011 test, volunteers viewed upsetting pictures twice, twelve hours apart. Those who slept in between showed less activity on the second viewing in the amygdala, the brain's alarm centre, than those who stayed awake, and rated the pictures as less intense. Other studies have found that sleep can preserve emotional reactions instead, so this remains an open question rather than settled science.

Sleep scienceRead card

DriveHealth

Regular exercise, from brisk walking to strength training, can ease the symptoms of depression, including mild to moderate depression, large reviews of clinical trials find. It can be a useful part of treatment but is not a universal substitute for clinical care.

One of the largest reviews so far, published in the BMJ in 2024, pooled 218 trials with more than 14,000 people. Walking or jogging, yoga and strength training helped most, and harder effort brought bigger benefits, though even gentle activity helped. The effect of walking or jogging was moderate, about the size seen with cognitive behavioural therapy. Possible reasons include better sleep, lower inflammation and growth factors that help brain cells form new connections, along with plainer ones: routine, a sense of achievement, time outdoors and time with other people. The benefit does not depend on losing weight. Anyone with depression should still talk to a doctor about the right mix of treatments.

Public health researchRead card