Mind & body, in brief

A normal heartbeat starts in a small cluster of cells called the sinus node. Its signal spreads across the two upper chambers, the atria, then reaches the lower chambers, which squeeze and pump blood out. [1]

In atrial fibrillation the signals start in many places across the atria at once. They fire 300 to 500 times a minute, so the atria quiver instead of beating. [2]

A small relay between the upper and lower chambers cannot pass all those signals on. Enough get through to make the lower chambers beat unevenly, sometimes as fast as 175 beats a minute. [3]

A quivering chamber does not push blood out properly. Blood pools inside the heart, and a clot can form there. [2]

If a clot travels out of the heart it can block blood flow to the brain. Atrial fibrillation is linked to about five times the risk of that kind of stroke. [4][5]

About one person in 11 aged 65 and over has atrial fibrillation. Some feel a racing, fluttering heart, and some feel nothing at all. [3][6]

In people who have already had a stroke, finding atrial fibrillation and starting a blood thinner cuts the risk of another stroke by about 60%. [7]

About half a billion smartwatches now carry a pulse sensor. In large studies run with Apple, Fitbit and Huawei, between 0.23% and 1% of wearers were sent an irregular-rhythm alert. [8]

Pooled across studies, watches picked up atrial fibrillation in 95% of the people who had it. They correctly cleared 97% of the people who did not. [9]

Doctors count an episode as atrial fibrillation once it lasts 30 seconds on a heart tracing. Depending on that definition and the device, device-found episodes turn up in 30% to 60% of the people being monitored. [10]

Stroke risk climbs with how long the episodes last. It was under 1.68% a year for episodes under six minutes and over 4% a year for episodes longer than a day. [10]

Two trials tested blood thinners for episodes found only by a device. NOAH-AFNET 6 was stopped early because too few strokes happened, while ARTESIA found apixaban cut strokes by 37% but caused more bleeding. [10]

A 2026 analysis of screening trials found continuous monitoring nearly tripled diagnoses and doubled blood-thinner use. Neither continuous nor occasional screening clearly cut strokes, bleeds or deaths on its own. [11]

One treatment, ablation, uses heat, cold or short electrical pulses to scar the small areas of heart tissue that start the faulty signals. [12]

Why it matters. Current US guidance backs blood thinners for device-found episodes only when they last over 24 hours in higher-risk people, and the review of ARTESIA argues that line may need checking again. [10]

Researchers at Cleveland Clinic, a large US hospital group, reported in July that a chemical made by gut bacteria is linked to atrial fibrillation. [25] The chemical is called TMAO. The team measured it in blood from more than 5,000 people having heart procedures, and tested it on heart cells in the lab. [25] In those cells it changed the heart's electrical environment and made abnormal rhythms more likely. [25]

Why it matters. The same team had already linked high TMAO to kidney disease, heart attack and stroke. [25] A researcher on the team said the finding may open a way to act earlier through diet, though blood samples and lab cells show a link, not proof. [25]

Prediabetes means blood sugar above the normal range but below the line for diabetes. [26] A review published in November pooled 11 studies covering more than 15 million people and 277,164 new cases of atrial fibrillation. [26] People with prediabetes had about a 20% higher risk than people with normal blood sugar. [26] The studies did not all use the same definition, because guidelines set the prediabetes line in different places. [26]

Why it matters. Diabetes was already an established risk factor for the rhythm problem, and this places some of the risk below the diabetes line. [26] Results varied a lot between studies, and the authors checked whether the definition used was one reason. [26]

A review of atrial fibrillation in COVID-19 gathered hospital data from across the pandemic. [27] In one study of 30,999 patients at 120 centres, 5.4% developed atrial fibrillation for the first time while in hospital. [27] Nearly half of those patients died during that first stay. [27] Inflammation from the infection disturbs the heart's upper chambers, which the authors say helps start the rhythm and keep it going. [27]

Why it matters. A new irregular rhythm in a very sick patient marks someone at high risk of intensive care, clots and death. [27] It shows the rhythm can be set off by something outside the heart.

A Cleveland Clinic heart researcher, David Van Wagoner, explained in June why atrial fibrillation often begins during sleep. [24] The heart normally slows at night, and a slower rate lets other clusters of cells start firing their own signals. [24] Sleep apnoea, where breathing stops for moments during sleep, raises pressure in the chest and strains the heart. [24] Atrial fibrillation is more common in people with sleep apnoea, high blood pressure and obesity. [3]

Why it matters. Many people have both sleep apnoea and atrial fibrillation without realising it. [24]

Doctors in a study gave a Withings Scanwatch to patients recovering from heart surgery, and checked it against hospital monitors for 24 hours. [28] Atrial fibrillation follows 20% to 30% of such operations. [28] Of 260 patients, 32 had the rhythm, and the watch picked up 69% of them. [28] When the watch raised an alarm it was right 87% of the time. [28]

Why it matters. The authors concluded the watch cannot replace hospital monitoring for these patients. [28] Its 69% is well below the 95% pooled across other smartwatch studies. [9]

FibriCheck is an app that reads the pulse through a smartphone camera and flags atrial fibrillation. [29] A study at several centres in different countries tested it on 236 people. [29] It found 96.3% of the people with the rhythm and correctly cleared 99.3% of those without it. [29] It worked less well in people with darker skin and higher body weight, until a technician checked the readings. [29]

Why it matters. A tool that works less well on darker skin gives some groups less accurate results unless a person checks. [29] Most earlier tests of the app had been small studies at single European centres. [29]

A review published in November looked at 37 studies of energy drinks and the heart. [30] The studies covered 1,597 people with an average age of 22.6, and Red Bull and Monster were the brands most tested. [30] The review reported raised heart rate and blood pressure after drinking them. [30] It also reported a longer QT interval, a stretch of the heartbeat where changes can signal a risk of rhythm problems. [30]

Why it matters. The energy drink industry is worth about 74 billion US dollars. [30] The studies measured short-term effects in young adults, not whether regular drinking causes heart disease.

About a quarter of strokes caused by a blocked blood vessel have no clear cause after full tests. [7] A trial called WATCH AFib plans to fit 400 such patients with both a smartwatch and an implanted heart recorder for six months. [7] Short hospital monitoring finds new atrial fibrillation in only about 2% to 6% of stroke patients. [31] Implanted recorders find it in 17% to 25% within a year. [31]

Why it matters. Finding the rhythm changes treatment, because blood thinners cut repeat strokes. [7] The trial will compare how well a watch and an implanted recorder find it in the same patients. [7]

Doctors decide on blood thinners partly with a points score called CHA2DS2-VASc, which adds up age and other conditions. [32] A 2026 study built computer models using only age, other illnesses and blood tests in people newly diagnosed with atrial fibrillation. [32] The models ranked stroke risk far better than the score in outside groups, with a score of 0.88 against 0.61 on a scale where 1 is perfect. [32] A Finnish study found dropping the extra point given for being female worked slightly better. [32]

Why it matters. The points score decides who is offered a blood thinner, so a point added or removed moves people across the treatment line. [32]

Researchers in Umea, Sweden, followed 1,277 people aged 85 and over through home visits between 2000 and 2017. [21] Over five years, 184 of them broke a hip, and 47.8% of those died within a year of the fracture. [21] Depression, an earlier stroke and breaks just below the hip joint raised the risk of dying. [21] Carrying extra weight went with a lower risk. [21]

Why it matters. Across older adults generally, 20% to 24% die within a year of a hip fracture and about a third need a care home. [33] Among the very old, the Swedish figure is about double that.

Clalit Health Services, an Israeli health provider, holds records for 40,391 members aged 65 and over who broke a hip between 2016 and 2023. [20] Of them, 17,364, or 43%, had another fracture during the study period. [20] A diagnosis of osteoporosis at the time of the first break predicted a second one. [20] So did an earlier stroke, depression and being female. [20]

Why it matters. A first broken hip is a warning that more breaks are likely. [20] The authors argue for targeted prevention in the people most at risk after that first break.

Doctors in China looked back at 259 patients aged 65 and over who had surgery for a broken hip in 2020 and 2021. [34] Some were given denosumab, a drug that slows the cells that break down bone. [34] After matching similar patients, 8.8% of those on the drug had a second hip fracture, against 29.7% of those not on it. [34]

Why it matters. The study looked back at records rather than randomly assigning the drug, so other differences between the groups may explain part of the gap. [34] It fits the Israeli finding that a first hip fracture often leads to another. [20]

A review published in January gathered ten years of UK research on why people over 50 are not treated for osteoporosis. [35] Bone loss begins between ages 30 and 40, and by 80 the average person has lost more than half their bone mass. [35] The review found a large gap between who needs treatment and who gets it, despite effective drugs and national guidelines. [35] Causes included missed diagnoses, low sense of risk and people not keeping up their medicine. [35]

Why it matters. The authors call for stronger fracture liaison services, teams that check bones after a first break. [35] They also call for better access to scans and support to keep taking medicine. [35]

In 1972 and 1973, 12,900 Oslo men aged 40 to 49 reported how active they were and had their height and weight measured. [36] Linking to national records, 1,542 of them, or 12%, later broke a hip, at a median age of 82. [36] Men who were inactive in midlife had a 38% higher risk than active men. [36] The highest risk was in men who were both inactive and thin. [36]

Why it matters. Research on preventing hip fractures in men is limited. [36] The link rests on one questionnaire, and the men's habits may have changed over five decades.

Korea's emergency department injury records covered 170,095 people aged 65 and over who came in after a fall between 2011 and 2020. [37] The share with a broken hip rose with age, with odds over four times higher at 85 and over than at 65 to 74. [37] Falls inside hospitals and nursing homes were more likely to break a hip than falls at home. [37]

Why it matters. The authors say fall prevention should be aimed at nursing homes and hospitals, where falls more often broke a hip. [37]

Two studies drew on the Global Burden of Disease 2021, a worldwide health database. [38][39] Falls cause about 684,000 deaths a year. [38] The number of hip fractures from falls in older people rose from 1990 to 2021 and is projected to keep rising to 2036, while the rate per person falls. [38] Among women around menopause, there were 300,104 cases at ages 50 to 54 in 2021, against 164,196 at ages 45 to 49. [39]

Why it matters. The count rises because there are more old people, even as each person's risk drops. [38] A rising count and a falling rate are both true at once.

Doctors described a 92-year-old woman whose bone scans put her fracture risk below the line for treatment. [40] Her spine read normal and her hip read as osteopenia, the milder zone between minus 1 and minus 2.5. [40] Soon after, she had a spontaneous fracture in her spine. [40] Wear in the spine can make a scan look healthier than the bone really is. [40]

Why it matters. About one in three adults over 50 without osteoporosis has osteopenia. [41] The case shows a person on the safe side of the treatment line can still break.

A review published in September looked at bone health in older people who compete in sports such as running. [42] Their training can match professional volumes. [42] High-impact exercise usually thickens bone, yet it also raises the risk of stress fractures, small cracks from repeated load. [42] Many older athletes do not know their bone density has fallen, and the review stresses scans and rest. [42]

Why it matters. The same running that protects bone in most people can crack it in someone whose bone is already thin. [42] Fitness is not a reliable sign of strong bones.

A review published in October looked at recovery after hip fracture in older people with memory problems. [33] Cognitive impairment is common in these patients and raises the risk of falls, slow recovery and moving into care. [33] People with mild to moderate impairment still made real gains with intensive, tailored exercise programmes. [33] Such programmes are often blocked by untrained staff, few resources and no agreed rules on who qualifies. [33]

Why it matters. The review says people with dementia can gain from rehab that many programmes are not set up to give. [33]

A review published in February pooled research on more than 500,000 health workers. [17] Burnout rose from about 32% before COVID-19 to 46% to 52% at its peaks, and 24% to 34% of frontline staff had PTSD. [17] Doctors with burnout had 2.72 times the odds of reporting medical errors. [17] Being sued then deepened depression and thoughts of suicide. [17]

Why it matters. The review describes burnout, PTSD and errors each making the others worse. [17] Its authors call for workload limits, psychological support and blame-free reporting of errors. [17]

Researchers surveyed 200 doctors and nurses at Modibbo Adama University Teaching Hospital in Yola, in Nigeria's Adamawa State. [18] Using the standard Maslach burnout questionnaire, they found 70% had burnout. [18] Low sense of achievement was the most common part, at 51.5%, with high exhaustion at 29%. [18] The state has severe staff shortages as doctors and nurses emigrate. [18]

Why it matters. Emigration and a growing workload fall on the staff who remain. [18] Patients in a state with severe staff shortages depend on them.

An anonymous survey in July and August 2025 asked doctors and trainees at a large hospital in Catania, Sicily, about burnout. [43] 76.7% reported low gratification from their work and 70.8% high depersonalisation, treating patients as objects. [43] Nearly half had high emotional exhaustion. [43] Women and doctors who qualified after 2020 had lower gratification and more distress. [43]

Why it matters. The survey covered one hospital, so it cannot say whether the same holds across Italy. [43]

An academic emergency department in the US surveyed its doctors and practitioners with the Maslach questionnaire. [19] Of 55 who replied, 52.7% had burnout. [19] Those with six or fewer days off a month had 4.7 times the odds of burnout. [19] So did those with fewer hobbies and less than four hours outdoors a week. [19]

Why it matters. The survey had only 55 replies, so the size of each link is uncertain. [19]

Singapore's National University Polyclinics surveyed 228 doctors, nurses and other staff in 2024. [44] Doctors reported more emotional exhaustion than other staff. [44] Staff who exercised less and scored lower on resilience were more exhausted. [44] Staff who felt more recognised by patients showed less depersonalisation. [44]

Why it matters. The survey shows links at one moment, not causes. [44]

Four hospitals in Tehran, Iran's capital, surveyed 723 health workers during the country's third COVID-19 peak. [45] Using the Copenhagen Burnout Inventory with a cut-off score of 50, 67.41% had moderate to high burnout. [45] Frontline, female and married workers scored highest. [45] Workload, lack of control and poor communication from leaders were all linked. [45]

Why it matters. The Tehran and Yola figures used different questionnaires and cut-offs, so the two cannot simply be ranked. [45][18]

A US hospital tested a daily meditation app on its emergency department nurses for four weeks. [46] Twelve nurses signed up and six finished both surveys. [46] The results showed no significant change in burnout or well-being. [46] A second analysis that filled in missing answers did show a drop, which is a weaker kind of evidence. [46]

Why it matters. Six nurses is too few to show whether the app helps. [46] Other surveys today link burnout to hours and days off. [19]

Researchers interviewed 20 final-year nursing interns who had burnout symptoms at three hospitals in western China. [47] The interns described heavy workloads, rigid rules and no voice. [47] They also described unpaid tasks and a lack of respect treated as normal. [47] Their hopes for the job clashed with what they met on the wards. [47]

Why it matters. Nursing already faces chronic staff shortages and heavy workloads after the pandemic. [48] These interns met the same pressures before they had qualified. [47]

Scientists at Washington University in St Louis reported in the journal Cell in December that ADHD stimulants act on brain networks for wakefulness and reward. [49] They did not act on the attention networks, as had long been assumed. [49] The team used brain scans of nearly 5,800 children aged 8 to 11, of whom 337 had taken a stimulant that morning. [49] The drugs' effects looked like the effects of more sleep. [49]

Why it matters. Stimulants improved school grades in children with ADHD and in children who were short of sleep. [49] The researchers suggest that getting enough sleep could help in similar ways. [49]

The CDC, the US public health agency, published data in December on adults with ADHD. [16] In 2023 about 15.5 million US adults had a diagnosis. [16] More than half, 55.9%, were first diagnosed as adults. [16] Visits to health centres by adults with ADHD were highest at ages 18 to 24 and fell steeply with age. [16]

Why it matters. ADHD was long seen as a childhood condition, and adult diagnosis is now a large share of the total. [16] That feeds the debate over whether adult ADHD is being over-diagnosed. [13]

A commentary published in September set out why adult ADHD may be over-diagnosed in the US. [13] The current US diagnostic manual raised the latest age for first symptoms from 7 to 12. [13] It also cut the symptoms an adult needs from six to five. [13] Stimulant prescriptions rose 30% from 2018 to 2022, leading to shortages, and US regulators wrote to doctors in 2023. [13]

Why it matters. The authors name rushed assessments, faking, phone distraction and other illnesses that harm attention as further causes. [13] The commentary does not put a number on how many diagnoses are wrong.

A US survey covered 224,469 undergraduates at 395 universities between 2019 and 2022. [50] 9.6% had an ADHD diagnosis, 5.1% had taken medicine for it in the past year, and 2.4% had misused a stimulant in the past three months. [50] For every one-point rise in a campus's share of medicated students, misuse was 7% higher. [50]

Why it matters. More prescriptions put more pills in circulation for students who were never prescribed them. [50] Students with ADHD who were not on medicine were 40% more likely to misuse. [50]

Swedish national records identified 9,283 people taking ADHD medicine who went on to have a substance use disorder between 2006 and 2020. [51] They were compared with 46,401 similar people on ADHD medicine without one. [51] Those with substance problems were about twice as likely to stop their ADHD treatment within a year. [51] They were also less likely to restart it. [51]

Why it matters. Guidelines recommend treating ADHD in people with substance problems, yet it remains disputed, and this shows who drops out. [51]