Mind & Body · Thursday, 5 November 2026

One in four of the world's adolescents reported no active day in the previous week, and 15 years have brought no progress, WHO finds

36 stories 44 sources

Signals on this beat

The bar and the word are our reading of how hard each one is pushing, and the arrow is where it is heading.

Big numbers worked out at a desk High↑

The WHO's 1.6 million lives comes from modelled projections of 6 climate steps. [4]
A US study turns drinking into a lifetime risk of 1 in 25 at 14 drinks a week. [17]
University of Washington researchers calculate 2 billion extra dark school trips. [19]

Children's daily routines Building↑

1 in 4 adolescents reported no active day in the previous week. [1]
Permanent summer time would send more US pupils to school in darkness. [19]
Childcare centres often set one nap for all, whatever a child's age. [26]

Care paid for by someone else High↑

The NHS in England spends nearly £2bn a year on charity and voluntary services. [14]
Belfast's new maternity hospital could cost almost £10m more. [16]
Norfolk's hospitals are reviewing options that include closing 2 birth units. [15]

US health rules at the ballot box Building↑

55% of US voters said Trump's policies made their health costs worse. [7]
Missouri voters kept a right to abortion, and Idaho kept its ban. [10]
At least 24 states have fetal personhood wording in their laws. [12]

Small studies making big claims Steady→

One month of early eating in 23 men was linked to a brain looking about 9 months younger. [22]
Cold showers looked good in a preprint that has not been peer-reviewed. [23]
A toothbrush trial covered 109 adults for 3 months. [27]

The stories

36 stories on this beat today.

Every story told the same way: what happened, who is involved, why it matters, how it works, the truth and the good news.

01
One in four of the world's adolescents reported no active day in the previous week, and 15 years have brought no progress, WHO finds

240 million

adolescents aged 11 to 17 with no active day in the previous week

that is 1 in 4 of them worldwide [1]

2.7 days

of activity a week, the global average in 2025

it was 2.7 in 2010 too [2]

28% vs 22%

of girls and boys with no active day

only 11% of girls were active every day, against 17% of boys [1]
What happened
- 1 in 4 adolescents worldwide reported no active day in the previous week, the WHO says. [1] The WHO is the UN's health agency. [1]
- That is about 240 million people aged 11 to 17. [1]
- An active day means at least 60 minutes of moderate-to-vigorous activity. [2] It can be at school, on the way there or in free time. [2]
- On average they were active 2.7 days a week. [1] Only 14% were active on all 7. [1]
- The average was 2.7 days in 2010 and 2.7 in 2025. [2]
- The numbers come from 389 surveys of 3.2 million adolescents in 140 countries and territories. [1]
- The study appears in The Lancet Global Health, a medical journal. [1]
- 28% of girls reported no active day, against 22% of boys. [1] Only 11% of girls were active every day, against 17% of boys. [1]
- Girls' activity falls as they grow older, which widens the gap with boys. [2]
- In Sweden, 16 girls aged 12 to 18 who play floorball, an indoor team sport, were interviewed about periods. [3]
- They described discomfort, tiredness and fear of leaking. [3] Discomfort was often managed in silence, out of embarrassment. [3]
- Finland, Canada and Serbia were most active, at 4.5 to 4.8 days a week. [2] Cambodia, Jordan and Madagascar were lowest, at 1.7 to 1.9. [2]
- In wealthier regions, about 7% had no active day: 6.9% to 7.7%. [2] In poorer regions it was 22.7% to 33.1%. [2]
- Richer countries can pay for open spaces and safe walking and cycling routes, the authors say. [2]
Who is involved
- 16 Swedish floorball players aged 12 to 18
- The WHO the UN's health agency; it released the new estimates
- Tedros Adhanom Ghebreyesus head of the WHO; he says the fix is safer places to move, not telling teens to try harder
- Girls aged 11 to 17 the group furthest behind in almost every country
How it unfolded
1. 2010 adolescents average 2.7 active days a week [2]
2. 2025 the average is still 2.7 days [2]
3. 2030 the WHO's target date, which no country is on track to meet [2]
Why it matters

Inactivity is a major risk for heart disease, type 2 diabetes and some cancers. [1] Regular activity in these years brings benefits lasting into adulthood. [2]

How it works

Public health calls this the built environment: WHO says transport, safe spaces and schools shape how teens move. [1]
Where safe routes and spaces are few, a teenager has fewer chances to move. [1] So the WHO says persuading teens is not enough. [1]

Seen it before

A child told to read more will read little in a house with no books.
The truth
- What is really going on The WHO found 240 million adolescents with no active day in the previous week by asking them, and it reached 1.6 million lives saved by modelling. [1][4]
- All this is what teenagers reported, not what a device recorded. [1] The surveys reach 59% of the world's adolescents, not all of them. [2]
- WHO chief Tedros Adhanom Ghebreyesus said: 'The answer is not to tell adolescents to try harder.' [1]
- Nobody knows yet
  Why adolescents' activity has not moved in 15 years.
  
  The WHO says there is no single explanation, and it lists transport, safe spaces, school, money, social norms and screens. [1]
Good news
- In some countries just 4% of adolescents reported no active day in the previous week.
- Finland, Canada and Serbia average 4.5 to 4.8 active days a week among their adolescents.
What comes next

The WHO wants 15% fewer teens missing the daily target by 2030. [2] No country or region is on track, the report found. [2]

02
WHO sums up 6 climate steps at 1.6 million lives
What happened
- The WHO says 6 climate and health steps could prevent 1.6 million deaths a year. [4] That is about 1 death in every 40. [4]
- The steps include warnings of dangerous heat, safe drinking water, toilets and handwashing. [4] Others are cleaner cooking fuel and better-set fuel prices. [4]
- Fuel pricing means ending wasteful subsidies and taxing fuels properly. [4] It accounts for 1.2 million of the 1.6 million. [4]
- Heat warnings are among the best value: about $835 back for every $1 spent, the WHO estimates. [4]
- An estimated 3.6 billion people live where climate change can harm them most. [5]
Why it matters

The WHO says gains would be largest in low- and middle-income countries, narrowing gaps in health and money. [4]
How it works

Health economists call this cost-benefit analysis: the WHO turned deaths, emissions and output into money, then set them against costs. [4]
It compared 2024 to 2075 with the steps and without them. [4] The WHO's yearly figures come from the gap between those two futures. [4]

Seen it before

Before buying a bus pass, you add up the fares it saves and compare them with its price.
Why 'could save millions of lives' is a sum, not a count

Epidemiologists call it attributable risk: take a harm measured in a study, multiply it by the people who face it, and print the answer as lives.

The twist

A number like 1.6 million lives saved has no list of names behind it. It is a sum, and it changes when its assumptions change.
The picture
Fuel pricing1.2 million deaths a year · 75%
The other 5 steps0.4 million deaths a year · 25%
The WHO's estimate of 1.6 million deaths prevented. Look at how much of the total rests on one step.
Step by step
1. A study measures how much a risk or a change affects people
2. Researchers estimate how many people face that risk
3. They assume how many people would make the change
4. They multiply it out, country by country
5. The answer is printed as lives saved
The same force, elsewhere today

Where this chain is also running, in today's other stories.
- The WHO's 6 climate steps
  
  The 1.6 million comes from comparing a future with the steps against one without, and the WHO itself calls its rollout plans aspirational.
- A drink's lifetime risk
  
  The 1 in 25 comes from multiplying US drinking surveys by published disease risks, so it describes a population and no single drinker.
- Plant milk and iodine
  
  The rise to 65% of teenage girls comes from assuming typical levels of added iodine in the swapped products, and nobody was measured after switching.
- Permanent summer time
  
  The national 2 billion dark trips comes from assuming pupils leave at about 8am, and the authors say that may make it too low.
Where you've seen this

Seat-belt laws

lives saved are worked out from crash rates and how many people buckle up

Weather forecasts

a 70% chance of rain is a calculation from many simulated runs, not a count of wet days

Insurance prices

a premium adds up likely claims across many customers, and no one knows who will claim

The catch

A modelled number can point the right way and still be wrong on size, because the people it assumes will change often do not.

And the whole of it

A government reads one round number and decides. A teenager, a drinker or a parent is somewhere inside that sum and will never know whether it was about them.
The truth
- The WHO lists its own limits: hopeful rollout plans, thin evidence in places and uncertain long-range forecasts. [4]
- Who gains Governments that end fuel subsidies — The WHO puts their money gain at US$5.4 trillion a year in fiscal benefits. [4]
- Nobody knows yet
  How many governments will act on the 6 climate steps.
  
  The WHO released its sums before COP31, and governments have not yet shared their commitments there. [4]
What comes next

The WHO released the report ahead of COP31, the next round of UN climate talks. [4]

03
Cocaine passes heroin in drug death figures
What happened
- Cocaine was linked to 1,233 deaths registered in England and Wales in 2025. [6] Heroin or morphine was linked to 1,210. [6]
- It is the first time cocaine has passed heroin, and cocaine deaths have nearly quadrupled in a decade. [6] Both counts fell from the year before. [6]
- All drug poisoning deaths came to 5,519, the Office for National Statistics says. [6] Opiate and opioid drugs combined were still linked to more deaths than cocaine. [6]
- Ketamine was linked to a record 115 deaths. [6] A decade earlier the number was 7. [6]
- James Morgan, an addiction researcher in London, puts that down to lower prices and the drug becoming normal. [6]
- Nitazenes are man-made opioids that can be many times stronger than heroin. [6] They have been linked to hundreds of UK deaths. [6]
Why it matters

The death rate in North East England is more than twice London's. [6] Morgan calls this growing polarisation between regions. [6]

How it works

Toxicology, the study of poisons, starts from the dose, and charities say cocaine's growing purity brings much higher risk. [6]
Purer cocaine means a user's usual amount holds more of the drug. [6] Mike Trace, who runs an addiction charity, also blames stronger opioids like nitazenes. [6]

Seen it before

The same cup of very strong coffee keeps you awake far longer than a weak one.
The truth
- These figures count deaths when registered, which lags behind when they happened. [6] James Morgan warns against over-reading the small fall in cocaine deaths. [6]
- Who pays People in England's former industrial areas — The steepest rises in drug deaths came where poverty and unemployment date back to the 1980s. [6]
- Nobody knows yet
  How many of the 1,233 cocaine deaths were caused by cocaine alone.
  
  Mentions on a death record include people who also took opioids, and families say slow blood tests can leave a cause unknown. [6]
Good news
- The overall death rate fell from 93.9 per million, the first yearly fall since 2012. [6]
04
A cheap drape shows when birth bleeding is too much
What happened
- A midwife in Kano, Nigeria, saved a 26-year-old mother with a thin plastic sheet and pouch. [41] The New York Times reported it. [41]
- It is called a maternal drape. [41] Blood runs into the pouch, and a mark shows the danger level of 300 millilitres. [41]
- Husaina Balarabe's bleeding passed that mark, so her midwife acted in time. [41]
- Bleeding after birth kills nearly 43,000 women a year and affects 27 million, a series in The Lancet estimates. [42]
Why it matters

It is the leading cause of maternal death around the world. [41]

How it works

Obstetrics now uses a calibrated drape to measure blood loss. [42] The series says judging by eye misses half of cases. [42]
A pouch with a line makes the loss plain. [41] Staff then start 5 treatments together, which can cut dangerous bleeding by up to 60%. [42]

Seen it before

A measuring jug beats pouring by eye, and you find out how much you poured before it overflows.
The truth
- The same series lists 6 delays, from diagnosis to treatment and blood supply, that often decide whether a woman survives. [42]
Good news
- A midwife in Kano, Nigeria, saw a mother's blood pass a line on a plastic pouch and acted in time. Husaina Balarabe, 26, lived to cuddle her newborn son, Aabid.
05
US voters tied their health bills to their vote
What happened
- About 6 in 10 US voters were very concerned about health costs, an election poll for KFF found. [7] KFF is a US health information group. [8]
- 55% said Trump's policies had made their own health costs worse. [7] 58% said they had made Americans' health worse. [7]
- In 2024 Trump led among voters most worried by health costs, 54% to 44%. [7] This time, about two-thirds of them in close states backed Democrats. [7]
- Standard Affordable Care Act plans are due to cost an average 13% more in 2027, KFF researchers say. [8]
- The Affordable Care Act is the US law behind subsidised private health plans. [8] Its extra help with premiums ended last year. [8]
- In Georgia, new governor Keisha Lance Bottoms promised full Medicaid, US health cover for people on low incomes. [9]
How it unfolded
1. January New US Congress sworn in
2. 15 January Sign-up ends
Why it matters

Democrats want the extra help back, but any law still needs Trump's signature. [8]

How it works

Political scientists call this retrospective voting: among voters blaming Trump for their costs, 83% backed Democrats for the US House. [7]
That blame crossed party lines. [7] Of voters who held it, 72% of independents and 22% of Republicans also voted Democrat. [7]

Seen it before

Fans judge a coach on last season's results, not on his plans for the next one.
The truth
- A poll shows what voters link, not what moved them. [7] Fuel and groceries worried them about as much as health costs. [7]
- Who gains US Democratic candidates on health — Half of midterm voters said Democrats handle health care better, a 20-point lead over Republicans. [7]
- Nobody knows yet
  How much US health policy can actually change.
  
  Democrats want Medicaid cuts undone, but Larry Levitt of KFF says all of that is impossible with Trump in the White House. [8]
What comes next

Sign-up for 2027 cover ends in most states on 15 January, soon after the new US Congress is sworn in. [8]
06
Four US states vote on abortion
What happened
- Voters in 4 US states decided abortion measures on Tuesday, a KFF analysis shows. [10]
- Nevada and Virginia wrote a right to abortion into their state constitutions. [10]
- Missouri voters rejected Amendment 3, which would have repealed the right to abortion they approved in 2024. [10]
- Idaho voters rejected a right to abortion, which leaves its near-total ban in place. [10]
- Since 2022, 12 states have passed ballot measures, usually to protect abortion rights. [11]
How it unfolded
1. 2024 Voters approve the right
2. This week Voters refuse to repeal it
Why it matters

Idaho keeps some of the country's most restrictive laws. [10] Abortion stays a protected right in Missouri, Nevada and Virginia. [10]

How it works

Lawyers call this a hierarchy of laws: a constitutional amendment carries stronger authority than an ordinary law. [11]
That is why both sides now take the question to voters. [11] A win in the constitution is harder to undo later. [11]

Seen it before

A headteacher's rule beats a class's own rule, so one teacher cannot quietly change it.
The truth
- Missouri's measure joined 2 questions, as it would also have banned gender-affirming care for minors, which 62% supported. [10] Voters said abortion mattered more, 45% to 8%. [10]
07
US embryo laws frighten IVF patients and doctors
What happened
- At least 24 US states have fetal personhood wording in their laws, KFF Health News reports. [12]
- Fetal personhood gives embryos legal rights from fertilisation. [12] IVF makes embryos in a lab, then freezes many of them. [12]
- In Louisiana, IVF embryos cannot be deliberately destroyed. [12]
- Allison Mertzman and her wife stored 9 embryos in Michigan for $3,000 a year. [12]
- The US Supreme Court ended the national right to abortion in June 2022. [12] The couple then feared a failed transfer could bring a legal case. [12]
- Doctors who provide illegal abortions in Texas or Alabama already face penalties of $100,000 or more, or prison. [12]
How it unfolded
1. June 2022 Abortion ruling
2. Summer 2022 They destroy their embryos
Why it matters

Fertility doctors fear felony charges and lawsuits that their malpractice insurance would not cover. [12]

How it works

Lawyers call this a chilling effect: unclear law stops people doing legal things, in case they are wrong. [12]
Mertzman was not ready to use her embryos. [12] She had them destroyed because moving them across states might bring a case. [12]

Seen it before

You skip a shortcut across a field when you cannot tell if it is allowed.
The truth
- Asked about safeguards for IVF doctors, the White House pointed to Trump's efforts to make IVF cheaper. [12]
- Nobody knows yet
  Whether an IVF doctor will be taken to court under these laws.
  
  Jessica Waters, a legal scholar, calls lawsuits over discarded embryos real possibilities, and the laws have not settled it. [12]
08
Migrant children wait months in US shelters
What happened
- Almost 1,900 children were in US government shelters for migrant children in September, KFF Health News reports. [13]
- One 9-year-old from El Salvador had been held for more than 7 months. [13] She told her mother she felt sad and lonely. [13]
- Her mother, with an asylum case pending and no criminal record, was arrested while seeking custody. [13]
Who is involved

The Office of Refugee Resettlement runs the shelters, under the US health department. [13]
How it unfolded

Before Trump's second term, children typically waited about a month while officials checked relatives. [13]
1. Before About a month
2. Now Months, with no clear end
Why it matters

Attorneys say some children now see only 2 ways out: long-term foster care, or back to what they fled. [13]

How it works

Child welfare law sets the standard: children go in the 'least restrictive setting' and leave without needless delay. [13]
Officials now arrest some of the parents who come forward. [13] So the adult a child needs for release may be locked up too. [13]

Seen it before

A child waiting at the school gate cannot leave if the adult collecting them has been stopped on the way.
The truth
- The US homeland security department says it does not separate families. [13] It lists 16 sponsors arrested for serious crimes. [13]
09
The NHS leans harder on charities
What happened
- The NHS in England spends nearly £2bn a year buying services from charities and voluntary groups, the BBC reports. [14]
- Cancer charities alone raise more than £1bn a year. [14]
- Dementia UK, a charity, funds video clinics that support more than 100 patients and relatives a week. [14]
Who is involved
- Dementia UK a charity paying for nurses
How it unfolded

In 1948 the NHS took most hospitals into public ownership, paid for by tax. [14] A 1980 law then encouraged a more active fundraising culture. [14]
1. 1948 Tax pays for hospitals
2. 1980 Fundraising returns
Why it matters

Parkinson's UK says its money has helped pay for around 70% of the specialist nurses in its field. [14]

How it works

Charities call this seed funding: a charity pays for a post first, and the NHS should take it on. [14]
WellChild, a children's charity, funds nurses for 3 years. [14] This year, for the first time, the NHS did not keep one post on. [14]

Seen it before

A friend pays your bus fare until your first wage arrives, then you are meant to pay it.
The truth
- 71% of health charities told a poll their contracts do not cover demand, but it dates from 2023. [14] NHS England says contract values rose in cash terms. [14]
- Who pays People with Parkinson's in the UK — They are the main donors to Parkinson's UK, whose chief calls funding nurses an additional tax on them. [14]
10
Two Norfolk birth units may close
What happened
- Norfolk has 3 maternity units, and the UK midwives' union is worried that 2 could close. [15]
- A review names consultant-led units at James Paget Hospital in Gorleston and Queen Elizabeth Hospital in King's Lynn. [15]
- Its options run from keeping services as they are to closing either unit, or both. [15]
- The hospital group says falling births, too few staff and more complex care make every site hard to sustain. [15]
Who is involved

Women from Lowestoft, north Suffolk, Wisbech and north-east Cambridgeshire also give birth there. [15]
- Lowestoft and north Suffolk
- Wisbech and north-east Cambridgeshire
How it unfolded
1. Now Review goes to NHS England
2. After Research and any consultation
Why it matters

The union warns that closure could mean women in labour travelling unacceptable distances. [15]

How it works

Hospital planners call these co-dependent services: the union says newborn and children's wards would close with birth units. [15]
Newborn units and children's wards rely on the birth unit beside them, the union says. [15] So one closure could take 3 services. [15]

Seen it before

Close a school's kitchen and its breakfast club stops too.
The truth
- Hospital chief Lesley Dwyer says no decision has been made and patient safety comes first. [15]
- Who pays Midwives at the 2 Norfolk units — Closures could mean being moved to work further from home, their union says. [15]
What comes next

The review goes to NHS England before further research and any public consultation. [15]
11
Belfast's new maternity hospital costs more again
What happened
- New problems could add almost £10m to Belfast's new maternity hospital, the BBC reports. [16] That takes the project past £100m. [16]
- Chemical flushing to clear bacteria from the water pipes damaged the pipework, the BBC understands. [16] More than 2,200 valves now need replacing. [16]
- The same health trust's mental health unit has now cost £9.4m in repairs and moving patients. [16]
How it unfolded

The building was handed over in March 2024. [16] It has stayed closed since, after a dangerous germ was found in its water. [16]
1. March 2024 Handed over
2. Since Closed, germ in the water
3. March 2027 Part of the building opens
4. November 2027 Newborn unit handed over
Why it matters

Daniel McCrossan, who chairs Northern Ireland's public spending committee, called it 'such terrible waste'. [16]
Mothers and babies keep using the older hospital until the new one opens. [16]
The truth
- The builder, Graham Construction, says water samples were clean at handover. [16] The trust puts repairs near £7m, against almost £10m in a report the BBC saw. [16]
- Nobody knows yet
  Who pays for the Belfast valves.
  
  The Belfast Trust refused to say whether contractors or taxpayers meet the repair costs, citing its work on liability. [16]
What comes next

The trust plans to open part of the building by March 2027. [16] The newborn unit follows by November 2027, if repairs work. [16]
12
A drink's risk, worked out over a lifetime
What happened
- A 2026 US study estimates the lifetime chance of dying from alcohol at different weekly amounts, The Conversation reports. [17]
- At about 7 US drinks a week, the lifetime risk of dying from alcohol passes 1 in 1,000. [17]
- At 8.5 drinks it passes 1 in 100. [17] At 14 it is about 1 in 25. [17]
- A US drink holds 13.6g of alcohol and a UK unit 8g. [17] So 8.5 US drinks is about 14.5 UK units. [17]
- The UK advises regular drinkers to stay under 14 units a week. [17] So its limit sits near that 1 in 100 line. [17]
- The WHO says no safe level of alcohol has been established for cancer risk. [17]
Why it matters

The limit was never a promise of safety, because 2016 experts put it just under 1 in 100. [17]

How it works

Epidemiologists call the old error confounding: some 'non-drinkers' in early studies were former drinkers who stopped because they were ill. [17]
That made non-drinkers look sicker. [17] So moderate drinkers looked healthier than they really were, and the idea that wine protects spread. [17]

Seen it before

A bench looks weak if you count injured players as people who chose to sit out.

The 1 in 25 comes from multiplying US drinking surveys by published disease risks, so it describes a population and no single drinker.
The idea, in story 02: Why 'could save millions of lives' is a sum, not a count →
The truth
- These are estimates for the US population, not forecasts for one drinker. [17] They rest on earlier research and the model's assumptions. [17]
13
Plant milk swaps could cut iodine
What happened
- Swapping a fifth to a third of dairy for plant products could leave more UK teenage girls short of iodine. [18] Modelling says 65%, up from 54%. [18]
- Among women aged 19 to 49 it would rise from 32% to 42%. [18]
- Iodine is a trace element the thyroid uses to make hormones for growth and brain development. [18]
- Of plant products on the UK market, 61% had added calcium and 46% vitamin B12. [18] Only 12% had added iodine. [18]
- The UK does not require vegan milk, cheese or yoghurt to have nutrients added. [18]
Why it matters

Young women are the group that matters most here, says Sarah Bath, a nutrition researcher at the University of Surrey. [18]

How it works

Nutrition scientists call this fortification: adding a nutrient to food. [18] Requiring iodine in these products would prevent the average falls. [18]
Dairy gives UK adults about a third of their iodine. [18] Take dairy away, and that iodine goes unless the replacement carries it. [18]

Seen it before

Swap your fruit snack for crisps, and the vitamins go unless something else brings them.

The rise to 65% of teenage girls comes from assuming typical levels of added iodine in the swapped products, and nobody was measured after switching.
The idea, in story 02: Why 'could save millions of lives' is a sum, not a count →
The truth
- This is modelling, not a measurement of people who switched. [18] A British dietitian says overall diet matters, so not everyone who switches goes short. [18]
- Who gains Danone's Alpro and Oatly — Both say their main plant drinks already have iodine added, so a call for fortification favours them over rivals without it. [18]
- Who pays Teenage girls in the UK — More than half already fall short on iodine, so a swap without added iodine lands first on them. [18]
14
Permanent summer time means dark school trips
What happened
- Keeping summer time all year would add at least 2 billion US school trips before sunrise. [19] That is a University of Washington calculation. [19]
- Georgia would see about 71 million more dark trips, and Washington state nearly 35 million. [19]
- Mississippi and Alabama each have about 2 million dark trips now. [19] Each would rise past 20 million. [19]
How it unfolded

The US House passed the bill this summer, and it has stalled in the US Senate. [19] 19 states have already approved the change. [19]
1. This summer US House passes it
2. Now Stalled in the US Senate
Why it matters

US traffic records show fatal crashes involving school-age walkers were about twice as likely on dark mornings as after sunrise. [19]

How it works

Chronobiology, the study of body clocks, says bright morning light sets the clock that times sleep, mood and appetite. [19]
Winter sunrise would come an hour later. [19] Children on fixed start times would then miss morning light while their bodies need it. [19]

Seen it before

A watch set an hour wrong makes you late all day until something corrects it.

The national 2 billion dark trips comes from assuming pupils leave at about 8am, and the authors say that may make it too low.
The idea, in story 02: Why 'could save millions of lives' is a sum, not a count →
The truth
- What is really going on Much of today's health news, from 2 billion dark school trips to a 1 in 25 drinking risk, is a number calculated at a desk from assumptions. [19][17]
- The 2 billion rests on assuming pupils leave at about 8am nationwide. [19] The authors say the true figure may be higher. [19]
- Who pays Children walking to US schools — They would walk to school more often before sunrise, which is the more dangerous time for them. [19]
15
A chemical may build up as the mind tires
What happened
- Glutamate, a common brain chemical, may help cause mental tiredness, a study in the journal PNAS suggests. [20]
- Hongmei Xia's team in Munich stimulated part of the brain's front with electrodes while people memorised letters. [20]
- The stimulation improved their scores. [20] But afterwards they were less willing to take on other hard mental tasks. [20]
Who is involved
- Hongmei Xia a PhD student in Munich
How it unfolded

In 2022 a team in Paris had found glutamate builds up after sustained mental effort. [20]
1. 2022 Glutamate found to build up
2. This week Stimulation study adds a test
Why it matters

Xia wonders whether the unpleasant feeling is a safety signal, since large amounts of glutamate can damage brain cells. [20]

How it works

Neuroscientists call glutamate a neurotransmitter: a chemical that passes signals between brain cells. [20]
Hard mental work leaves glutamate piling up faster than the brain can clear it, Xia suggests. [20] Motivation then falls, even when persisting would pay. [20]

Seen it before

Dishes pile up faster than one person can wash them, and at some point the cook stops.
The truth
- Mathias Pessiglione of the Paris Brain Institute says the study rules out a purely mental cause. [20] He thinks motivation and beliefs still matter. [20]
- Nobody knows yet
  Whether glutamate alone explains mental tiredness.
  
  Clay Holroyd's lab at Ghent University is also studying lactate, a fuel for the brain, and another brain region. [20]
16
A third of babies lost their peanut allergy
What happened
- In Australia, 35% of 778 babies diagnosed with peanut allergy showed no reaction when tested again. [25]
- The test feeds a baby rising doses of peanut flour under medical supervision, up to 2,500 milligrams. [25]
Who is involved

Tim Brettig of Murdoch Children's Research Institute leads the programme, and the result surprised his team. [25]
How it unfolded

Since 2024 Australia has offered free treatment to babies diagnosed before 12 months. [25] Babies must take this test first. [25]
1. 2024 Free treatment begins
2. First step The food test
Why it matters

Those children are spared a life of restricted food, worry and emergency medicine, Brettig says. [25]

How it works

Allergists call this an oral food challenge: the test of what a child does when actually fed the food. [25]
Diagnosis usually rests on past reactions and skin or blood tests. [25] Without a later challenge, nobody learns that the allergy has gone. [25]

Seen it before

A height mark on the door from last year does not tell you how tall you are today.
The truth
- Allergy treatments like this carry a risk of severe reactions, so they should happen only under medical supervision. [25]
- Nobody knows yet
  Why so many babies lost their peanut allergy so quickly.
  
  Tim Brettig says it may have been a passing immune response, but the study could not say. [25]
Good news
- For the 35%, parents were told their babies could safely eat peanut at home. [25]
17
Being alone shows in blood markers of age
What happened
- A study of 309,746 UK adults followed for about 14 years links loneliness and isolation with an older biological age. [21]
- Isolation is having little contact, such as living alone. [21] Loneliness is the feeling of being cut off, even among people. [21]
- The most isolated people were about 4 months older biologically. [21] The lonely were about 3 months older. [21]
- Biological age here comes from a formula using routine blood tests, including markers of inflammation and organ function. [21]
Who is involved
- Isolation few contacts
- Loneliness a feeling
Why it matters

Having no one to confide in mattered about as much as feeling lonely, the authors say. [21]

How it works

Gerontologists, who study ageing, call this biological age acceleration: blood markers looking older than a person's real age. [21]
Researchers suspect long stress, poorer habits and immune changes link being alone with that wear. [21]

Seen it before

Two bikes bought the same day look different after years, if only one was left out in the rain.
The truth
- The authors call these 'modest average differences', not months of life lost or predictions for one person. [21]
18
A month's early eating, in 23 men
What happened
- A small Chinese study had 23 men with metabolic syndrome eat only between 8am and 4pm for a month. [22]
- Metabolic syndrome is a cluster of risks such as a large waist, high blood sugar and high blood pressure. [22]
- Their brains looked 2.8 years older than their age before the month. [22] Afterwards that gap was 2 years. [22]
- The men lost about 4.4kg on average, and word-list recall rose by about 19%. [22]
- That is a drop of roughly 9 months, in a study in the journal Frontiers in Aging. [22]
Why it matters

Brain age matters because metabolic syndrome is linked with faster ageing of the brain and memory loss. [22]

How it works

Trial designers call this a before-and-after study: each man is compared with himself, with no separate group. [22]
All 23 men made the change, under close watch. [22] So nothing shows what the same month would have brought anyway. [22]

Seen it before

If all the class gets a new teacher and scores rise, you cannot tell if the teacher did it.
The truth
- The brain age figure is a computer estimate, not a measured age. [22] PsyPost also found the paper's main statistic did not match its stated significance. [22]
19
Cold showers and fewer sick days, unconfirmed
What happened
- Pooled results from 3 trials and 719 people found cold-shower takers reported 31% fewer sick days off work. [23] They reported 26% fewer illness days. [23]
- The work comes from psychologist Lena Glaser's doctoral research at the University of Basel in Switzerland. [23]
- Many people dropped out in the first 2 weeks, and the drop-out rate then fell. [23]
Who is involved
- Lena Glaser University of Basel
How it unfolded

A 2016 study found a similar 29% fall in sickness absence. [23]

Why it matters

Cold showers cost almost nothing, so researchers suggest workplaces might try them if results hold. [23]

How it works

Statisticians call this self-selection: results here grouped people by how often they took cold showers, not at random. [23]
People who keep up a hard habit may already differ from those who quit. [23] So their fewer sick days may have other causes. [23]

Seen it before

Runners on a team may be fitter because the fit ones are the ones who stayed.
The truth
- The paper is a preprint not yet checked by outside reviewers, and all the results are what participants reported. [23]
20
Tight underwear linked to poorer sperm
What happened
- A Chinese study compared 21,221 men in loose underwear with 5,615 in tight underwear. [24]
- Tight underwear was linked with 12% higher odds of fewer moving sperm. [24] It was linked with 48% higher odds of fewer normally shaped sperm. [24]
- It was also linked with 108% higher odds of more sperm with damaged DNA. [24]
- The Asian Journal of Andrology published it, and it is more than 40 times larger than a 2018 Harvard study. [24]
Why it matters

Men trying for a baby often hear this advice, and large evidence had been limited. [24]

How it works

Reproductive biologists call this scrotal heat stress: sperm develop best about 2 to 3 degrees below core body temperature. [24]
Tight briefs can raise that temperature by up to 1 degree. [24] That could affect the last stage of sperm development. [24]

Seen it before

Dough left too near a hot oven rises badly, even if nothing else about the recipe changed.
The truth
- All these men were seeking fertility checks and reported what they wore. [24] The study cannot show the underwear caused the difference. [24]
21
A self-powered toothbrush cuts plaque in a trial
What happened
- Peking University researchers gave 109 adults a new toothbrush or a nylon one for 3 months. [27] Plaque and bleeding fell about 40% against about 15%. [27]
- Its bristles make electricity as they bend, which creates molecules that damage bacteria. [27] No battery is needed. [27]
- In the lab it killed about 78% of a germ behind gum disease. [27] Nylon killed about 8%. [27]
Why it matters

Tooth decay and other mouth diseases affect nearly half the world's people. [27]

How it works

Materials scientists call this piezoelectricity: some materials make an electric charge when pressed or bent. [27]
Each stroke bends a bristle, and the charge forms reactive oxygen molecules. [27] Those molecules attack germs that brushing alone leaves behind. [27]

Seen it before

A clicker lighter makes a spark when you press it, with no battery inside.
The truth
- The trial was small and lasted 3 months. [27] Larger studies must show whether the brush really prevents disease. [27]
22
Brain scans hint at who wants rewards now
What happened
- A study in JAMA Psychiatry scanned the brains of 146 young adults. [28] It also tested how they weigh rewards now against later. [28]
- A computer model using white matter size explained 22% of the differences between people. [28] One using grey matter explained 19%. [28]
- White matter is bundles of nerve fibres. [28] Grey matter is the tissue that holds nerve cell bodies. [28]
Why it matters

Choosing now over later is linked with addiction and ADHD. [28] In one study, smokers who chose this way relapsed more after treatment. [28]

How it works

Psychologists call it delay discounting: a reward loses value the longer you wait. [28] Someone might take $20 today over $50 next month. [28]
People differ in how fast a waiting reward loses value. [28] Those who lose it fast tend to act on what is close. [28]

Seen it before

Eating 1 sweet now feels better to many children than getting 2 after dinner.
The truth
- The models left most of the differences unexplained. [28] The report calls this early proof of concept. [28]
23
Does the basic feeling of being alive sit in the brainstem?
What happened
- Marshall Devor and Mark Baron of The Hebrew University argue the basic feeling of existing starts in the brainstem. [29]
- The brainstem is the stalk joining the upper brain to the spinal cord. [29] Leading theories instead place consciousness in the wrinkled outer layer. [29]
- Mild currents on that outer layer almost never cause pain. [29] Even in its likeliest pain area, one study evoked pain at only 8 of 313 sites. [29]
Why it matters

Small strokes in the upper brainstem often put patients in a coma. [29] Wide damage to the outer layer does not remove raw consciousness, they note. [29]

How it works

Philosophers split phenomenal consciousness, the raw feeling of being, from access consciousness, what you are aware of. [29] The brainstem claim is about the first. [29]
Damage the outer layer, and specific abilities go but the feeling of being stays, they argue. [29] Damage the brainstem spot, and awareness itself goes. [29]

Seen it before

Turn off the television and the picture goes, but cut the mains and the whole house goes dark.
The truth
- This is a theory drawn from older work, not a new experiment. [29] Much of its key data comes from the authors' own rat studies. [29]
24
Mice with no hippocampus still learned a maze
What happened
- Some mice born without a hippocampus and most of the outer brain still learned a complex maze, a preprint reports. [30]
- The hippocampus is the brain area long treated as the main centre for navigation. [30]
- Those mice were 2 to 3 times slower at first. [30] Then they learned like normal mice, remembering a 9-turn route 3 to 4 weeks later. [30]
- A separate preprint shows ordinary mice carry location signals throughout the brain. [30]
Who is involved
- The hippocampus the brain's navigation centre, it was thought
Why it matters

Enny van Beest of University College London says navigation and decision-making now appear everywhere in the brain. [30] That leaves which networks do what. [30]

How it works

Neuroscientists call this plasticity: a developing brain can adapt its wiring, says Kevin Mitchell of Trinity College Dublin. [30]
These mice grew up without those areas. [30] So other areas may have taken over a job they would not normally do. [30]

Seen it before

A child who grows up left-handed after a right-arm injury learns to write with the other hand.
The truth
- Both papers are preprints on bioRxiv, a site for work not yet published in a journal. [30] Lisa Giocomo of Stanford remains sceptical. [30]
25
Why the brain crosses over: a new idea
What happened
- The left brain controls the right body, and the right brain controls the left. [31]
- Martin Wessendorf and Daniel Wang propose an explanation in the journal Frontiers in Neuroanatomy. [31]
- They suggest evolution built new brain circuits around an ancient visual system. [31]
- That system already crossed sides: objects on your left reach the right side of the brain. [31]
- The optic tectum, a very old brain part found in all animals with backbones, holds maps of the opposite side. [31]
Who is involved
- The optic tectum a map of the opposite side
Why it matters

One crossed circuit turns you quickly towards a car seen from the corner of your eye. [31]

How it works

Evolutionary biologists call this exaptation: an old part taking on a new job, as these authors argue crossed pathways did. [31]
Sight crossed first, the idea goes. [31] Later touch and movement circuits may have inherited that arrangement. [31]

Seen it before

A new road usually follows the old track, even when a straight line would be shorter.
The truth
- The authors offer this as a hypothesis about changes hundreds of millions of years old, from comparing circuits across animals. [31]
26
Covid and dementia: no clear rise on average
What happened
- A study in Scientific Reports checked recorded Covid against later diagnoses of Alzheimer's, Parkinson's or dementia. [32] Everyone was aged 70 or over. [32]
- It used records from Danish national registers, a US network and UK Biobank, a large health database. [32]
- Across these sources it found no consistent rise in average risk of diagnosis. [32]
How it unfolded

Earlier studies from health records had suggested a higher risk. [32]

Why it matters

Exploratory results hinted at higher risk in older people and those with diabetes, heart disease, depression or hearing loss. [32]

How it works

Epidemiologists call this emulating a target trial: using records to copy how a real trial would be designed. [32]
People tested and infected may differ from others in age and health. [32] Careful comparison groups try to remove those differences. [32]

Seen it before

You compare two runners fairly only if they ran the same course on the same day.
The truth
- The authors say the patterns in those groups varied and need confirming in independent studies. [32]
27
HIV prevention pills found in some blood donations
What happened
- Researchers tested 84 male donors in England whose 2023 blood showed signs of syphilis. [33] 6 samples, or 7.1%, held both drugs in a common prevention pill. [33]
- Prep is medicine people without HIV take to lower their chance of catching it. [33] UK rules make Prep users wait before donating. [33]
- The wait is 3 months after a tablet and 2 years after an injection. [33]
- Donations showing current or past syphilis rose from about 4 to 10 per 100,000 between 2018 and 2024. [33]
Why it matters

Blood services rely on donors' answers as well as tests, so people need to understand the reason for the wait. [33]

How it works

Blood safety experts call this the window period: a time when infection is present but tests cannot reliably find it. [33]
Prep can keep HIV levels low and delay antibodies. [33] So a new infection may slip past the tests, which is why the wait exists. [33]

Seen it before

A smoke alarm with a weak battery may stay silent even when the fire has already started.
The truth
- The same drugs treat HIV and have other uses, so finding them does not show a donor has HIV. [33] The authors did not show HIV passing through donated blood. [33]
28
One water test closed a US town's taps
What happened
- Center Township in Pennsylvania told people to boil water on 2 November. [34] One routine sample had tested positive for E. coli. [34]
- Central Valley school pupils learned from home on 3 and 4 November as a precaution. [34]
- E. coli is a common bacterium living in the guts of people and animals, and most strains do no harm. [34]
- The US Environmental Protection Agency sets a goal of zero E. coli in drinking water. [34]
How it unfolded
1. 2 November Boil-water advice issued
2. 4 November Advice lifted
Why it matters

Water flows through one connected system, so a problem in one place could reach others. [34]

How it works

Water engineers call E. coli an indicator: it shows human or animal waste got in, which can carry worse germs. [34]
A pipe break can drop the pressure and let dirty water in. [34] Boiling kills most harmful germs in under a minute while the fault is found. [34]

Seen it before

Muddy footprints do not hurt anyone, but they tell you someone walked in from outside.
The truth
- This account gives no cause for the positive sample. [34] One sample is a snapshot of one place and one moment. [34]
Good news
- The water authority lifted the advice on 4 November. [34]
29
Attacks earn US politicians more attention online
What happened
- A study of US Congress members looked at 4.7 million Twitter posts and 2.4 million Facebook posts. [35] It also covered 184,000 emails. [35]
- Attacks on opponents got 60% more likes and 80% more retweets than the same politician's average post. [35]
- Attacks made up about 5 to 10% of messages early on. [35] By the end of 2022 they were nearly 20%. [35]
- Posts on working with the other party or local help drew less attention than usual. [35]
Who is involved

Michael Kistner of the University of Houston led the work, in the American Political Science Review. [35]
- Michael Kistner University of Houston
Why it matters

Routine work, such as getting federal money for a local district, got less room as attacks grew. [35]

How it works

Psychologists call this reinforcement: a behaviour that earns a reward happens more, and likes give quick, countable feedback. [35]
A politician's team sees which posts get likes. [35] Attacks score best, so attacks can become more common. [35]

Seen it before

A child who gets a laugh by being rude in class tends to try it again.
The truth
- The researchers warn that online likes do not show what voters want. [35] Surveys find most voters prefer legislative work. [35]
- Who gains US politicians who attack opponents — Attacks bring them far more online attention than posts about local work. [35]
30
Reading emotion from moving dots, in schizophrenia
What happened
- A study in Germany tested 28 men with schizophrenia and 28 men without it. [40] They watched moving dots shaped as faces and bodies. [40]
- Those with schizophrenia read emotion in dot faces correctly about 59% of the time, against 76% for the others. [40]
- On dot bodies the figures were about 55% and 63%. [40] Pure guessing would score 50%. [40]
- Most of the patients had paranoid schizophrenia, and 8 had a related condition that adds mood symptoms. [40]
Why it matters

Trouble reading others can make relationships harder to start and keep. [40]

How it works

Psychologists call this social cognition. [40] They test it with point-light displays: moving dots with no clothes, face or body shape. [40]
Dots remove every clue except motion. [40] So any gap in scores points to reading movement itself, not to clothes or faces. [40]

Seen it before

You can spot a friend far off by the way they walk, before you can see their face.
The truth
- The study is small, covered only men, and nearly all the patients were taking medicine. [40]
31
A Little Ice Age may have weakened children's bones
What happened
- Teeth of 21 people buried from 1711 to 1829 in North Shields, England, show bands where calcium failed to set. [37]
- Those bands suggest repeated, seasonal shortages of vitamin D. [37] Some skeletons also showed rickets, a bone disorder. [37]
- The town had not yet industrialised, so smoky air probably was not the cause. [37]
- In the last 200 years of the Little Ice Age, northern Europe cooled by 2 to 3 degrees. [37]
Why it matters

Ellen Kendall of Durham University says the cold may have added an extra difficulty to getting enough sunlight. [37]

How it works

Bioarchaeology, the study of old human remains, reads teeth as a growth diary. [37] Gaps form when calcium fails to set. [37]
Cold kept children indoors or bundled up, Kendall suggests. [37] Less skin saw the sun, so bodies made less vitamin D. [37]

Seen it before

Rings in a tree trunk show which years were hard, long after those years have passed.
The truth
- Kendall calls climate one factor among many, alongside diet, pollution and gender roles. [37]
32
Stair machines: what the evidence says
What happened
- Stair climber machines have surged on social media, and an article in The Conversation checked the claims. [39]
- For heart fitness they roughly match running. [39] Blood pressure benefits match brisk treadmill walking. [39]
- In a small study of 30 men, the stair machine burned around 2 calories fewer a minute than a treadmill. [39]
- Muscle gains can match leg-press training, although that study covered only older adults. [39]
Why it matters

That matters to people who choose it for weight loss, where the evidence is less favourable. [39]

How it works

Biomechanics, the study of forces on the body, finds stairs bring lower impact than running. [39] One study still found 8 times the knee stress. [39]
Each step holds the muscle under tension for longer. [39] More tension brings bigger muscle gains, and lower arm use burns fewer calories. [39]

Seen it before

Holding a heavy bag still tires your arm more than swinging it past once.
The truth
- Much of this rests on small studies, some in one age group, so the fit for younger people is unclear. [39]
33
An arts charity prescribes 60 minutes of art
What happened
- Art Fund, a UK arts charity, suggests a 'recommended dose of art': 60 minutes a month, a Guardian column says. [38]
- Daisy Fancourt, a professor at University College London who studies this, wrote the report's foreword. [38]
- She says this goes alongside a balanced diet, regular exercise and time outdoors. [38]
- Columnist Emma Brockes says the 60 minutes appears entirely arbitrary. [38] She calls the dose one more item on a to-do list. [38]
Who is involved
- Daisy Fancourt University College London
- Emma Brockes Guardian columnist
Why it matters

Art Fund sells its idea by appealing to science, Brockes argues. [38]
The truth
- This account comes from a column, which does not set out the evidence behind the 60 minutes. [38]
34
Massachusetts keeps legal cannabis sales
What happened
- About 76% of Massachusetts voters rejected Question 8, a plan to end legal recreational cannabis sales, STAT reports. [43]
- About 24% backed it, with close to 90% of votes counted by Wednesday morning. [43]
Who is involved
- US national law still bans it
How it unfolded

Since 1996, 40 US states and Washington DC have legalised medical or adult cannabis, CNBC reported in August. [44]
Cannabis remains illegal under US national law. [44]

Why it matters

Polls show legal cannabis is popular in both main parties, although Republican support has been falling. [44]
The truth
- The result is clear, but the readable part of this report gives no reasons for how voters chose. [43]
35
Childcare naps may not fit every age
What happened
- A University of Queensland study asked parents of 188 children aged 1 to 4.5 in Brisbane about naps. [26]
- Children under 2.2 years napped less at childcare than at home. [26] Those over 4.3 years napped more there. [26]
- Many centres set one midday nap for all children. [26] Staff say this gives them time for paperwork and a quiet room. [26]
Why it matters

Some parents do not want naps at childcare, as they push back bedtime. [26]

How it works

Sleep researchers call this the nap transition: from several naps a day to one, then none, at different ages. [26]
Younger children may want 2 naps but get 1. [26] Older ones may have stopped napping at home, but are still encouraged to sleep. [26]

Seen it before

One bedtime for all brothers and sisters suits the middle child and neither of the others.
The truth
- Parents gave nap counts from memory, with no record of how long naps lasted. [26] A trial at 6 services found no sleep differences when staff adapted naps. [26]
36
Scholars may have measured the wrong thing in culture
What happened
- A study of more than 12,000 people across 100 cultures, in Nature Human Behaviour, questions how psychologists measure collectivism. [36]
- Collectivism means putting group ties and duties before personal wishes. [36] Surveys often failed to find East Asia scoring higher than the West. [36]
- In a test, 83% of scholars predicted people in China would agree more that relationships beat accomplishments. [36] Americans agreed more. [36]
Why it matters

Psychologists use such scales to compare countries, so a flawed scale gives a wrong picture of a culture. [36]

How it works

Psychologists call this construct validity: whether a survey measures the idea it names. [36] Thomas Talhelm's team says these did not. [36]
Old surveys mixed warm feelings about everyone with binding duties to close people. [36] Westerners score high on warmth, which hid real differences. [36]

Seen it before

Weighing fruit with the bowl still on the scale gives a number, but not the fruit's weight.
The truth
- Talhelm's team proposes a new word for the duty part, responsibilism. [36] It rests on this team's own new survey. [36]

Across the day

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36 stories on this beat today.

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What is true of the whole day.