Persistent money struggles linked to faster brain ageing

University College London

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Persistent financial hardship accelerates age-related cognitive decline, according to a new study led by University College London (UCL) researchers.

The study, published in Innovation in Aging, looked at data from 2,759 people in the UK who filled in questionnaires throughout their lives as part of the MRC National Survey of Health and Development (also known as the 1946 British cohort study).

The research team found that people who experienced either persistent money struggles or persistent low income in early and middle adulthood performed less well in cognitive tests by the age of 53.

Looking at a subgroup of people who had brain scans, the team found that those who experienced persistent low income had worse brain health (including more brain shrinkage) in later life (ages 69 to 71).

These links remained even after accounting for factors that might have skewed the results such as childhood cognition, education level and childhood disadvantage.

Corresponding author Dr Jacques Wels (Unit for Lifelong Health & Ageing at UCL) said: “Most studies on cognitive ageing look at financial hardship at only a single point in time. Our study using several decades of data allows us to see that it is the accumulation of hardship over many years that is linked to the worst cognitive health outcomes, rather than occasional episodes of adversity.”

Senior author Professor Praveetha Patalay (Unit for Lifelong Health & Ageing and Centre for Longitudinal Studies, UCL) said: “Our findings suggest that supporting people facing financial hardship and reducing chronic poverty could also help prevent cognitive decline and dementia cases in the future.”  

The research team found that the link between financial adversity and poorer brain health in later life was particularly strong for men, those who experienced childhood disadvantage, and those who carried a genetic variant, APOE-ε4, that raises Alzheimer’s risk.

Men who experienced persistent financial adversity also did less well in cognitive tests at aged 53 than female counterparts. Possible reasons for this difference might include that disadvantaged men may have worse health behaviours (such as smoking and alcohol misuse) than disadvantaged women and that men might experience the stress of financial adversity more, especially as they would have been the primary breadwinners in this cohort born in 1946. 

The researchers mention different mechanisms that could link cognitive ageing and financial hardship including inflammation, which is known to accelerate brain ageing and which is caused by chronic stress.

Another factor is that frequently worrying about money may increase cognitive load, leaving people with less bandwidth for other cognitive tasks.  

The researchers also said that, while those who experienced financial hardship or low income did less well on cognitive tests at 53, their performance in a memory test declined more slowly between 53 and 69, which was likely due to them already having suffered significant cognitive losses compared to counterparts who did not have persistent financial strain.

Study participants were asked about their household income at three points, at the ages of 26, 43 and 53, and classed as having persistent low income if they were in the bottom 20% of the group at least twice, which amounted to 16% (about one in six) of the participants.

Financial hardship was assessed using questions such as whether people found it hard to manage on their income and whether they had had trouble paying for bills. Participants were classed as having experienced persistent hardship if they scored above a threshold on the questionnaire at least twice between the ages of 36 and 53. This represented 12% (about one in eight) of the participants.

Cognitive tests assessed verbal memory and processing speed; magnetic resonance imaging (MRI) scans allowed researchers to measure factors such as brain atrophy (shrinkage) and ventricular expansion – i.e., the expansion of fluid-filled cavities in the brain – which is a sign of poor brain health.

The 1946 British cohort study, hosted by UCL, is the world’s longest continuously running birth cohort study. Participants (who were enrolled at birth) celebrated their 80th birthday earlier this year.

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Journal

Innovation in Aging

DOI

10.1093/geroni/igag054 

 

Sperm whales blow bubbles to achieve restful, vertical sleep

University of St. Andrews

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Sperm Whale at rest

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Credit: University of St Andrews

New research from the University of St Andrews and Université de Neuchâtel, has uncovered the mechanism which allows sperm whales to sleep in a unique vertical position, just under the ocean surface.

Sperm whales are the only whale known to rest vertically. It’s thought to enable them to sleep effectively by buffering them from surface wave action, while avoiding the energy needed to dive to deeper depths. However, until now, it’s been unclear how they maintained their position just below the sea surface. 

In a paper published in the Journal of Experimental Biology, researchers discovered that while resting, sperm whales release gas bubbles to help them regulate their buoyancy and remain below the sea surface. This regulation is crucial as Sperm Whales are positively buoyant naturally due to the large amounts of spermaceti oil in their heads. Additionally, sperm whales are breath-hold divers, if they slowly drift up while resting, the gas in their lung will slowly expand, releasing bubbles enables them to counteract the expanding diving gas and achieve neutral buoyancy.

Researchers were able to collect data from placing small tags using suction cups on Sperm Whales off the Norwegian coast.  The tags record sound and 3-D animal movements. Clear bubble sounds were recorded by the tags, and animal movement data was used to create a simulation based on tissue density, drag through the water and gas volumes in their body.

Results from the simulation confirmed that release of bubbles functioned to reduce the whales’ positive buoyancy, enabling them to remain submerged while resting. Additionally, the results indicate that sperm whales start resting dives with less diving gas volume than for deep foraging dives.

Professor Patrick Miller from the Sea Mammal Research Unit at the University of St Andrews said:  "This study confirms that sperm whales exquisitely control their buoyancy by releasing gases to remain submerged with near-neutral buoyancy just below the sea surface.  It is particularly fascinating they are able to make these fine-scale adjustments while they are thought to be asleep, a challenge totally alien to terrestrial mammals like us humans.”  

The authors suspect that releasing bubbles could be related to the off-gassing of excess CO2 or N2 from tissues into the lungs, so this behaviour could also have implications for metabolic gas exchange.

ENDS

 Audio of Sperm Whale off gassing [AUDIO] 

Sperm whale visualisation [VIDEO] 

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Journal

Journal of Experimental Biology

DOI

10.1242/jeb.251920 

Method of Research

Meta-analysis

Subject of Research

Animals

Article Title

Buoyancy regulation through modulation of onboard gas volume by resting sperm whales (Physeter macrocephalus)

 

More than half of the world's migratory bird species are declining, new global study finds

International team of scientists calls for a new approach to biodiversity conservation as losses span continents, oceans, and political boundaries

Georgetown University Medical Center

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(JULY 23, 2026) WASHINGTON, D.C. — More than half of the world's migratory bird species are declining according to a major new review led by researchers from Georgetown University, the Smithsonian’s National Zoo and Conservation Biology Institute, and a global collaboration of ornithologists.

Published in Nature Reviews Biodiversity, the paper provides the most comprehensive global assessment of migratory bird population status, threats, and conservation approaches, and presents a new framework for reversing population declines. The review synthesizes decades of research, international monitoring efforts, global biodiversity databases, and conservation agreements to identify what scientists know, where major knowledge gaps remain, and what actions are needed to reverse declines before more species become threatened with extinction.

The findings point to a broader challenge facing global biodiversity conservation. Because migratory animals, including birds, move across continents, oceans, and political boundaries throughout their annual cycles, they depend on interconnected networks of breeding grounds, migration stopover sites, and non-breeding habitats. As a result, they face a complex and often overlapping set of threats throughout their lives, making them among the most difficult groups of animals to conserve.

The authors estimate that approximately 51% of migratory bird species are declining globally across every major flyway on Earth. While nearly 300 migratory species are already considered globally threatened, many once-common and widespread birds are also experiencing substantial population losses, underscoring the scale of the biodiversity crisis.

"The scale of migratory bird declines is both alarming and sobering," said Peter P. Marra, Dean of Georgetown University's Earth Commons Institute and co-lead author of the study. "What we're seeing is the predictable consequence of decades of environmental degradation. Yet these declines are not inevitable. This review goes beyond documenting the crisis by identifying the major threats, highlighting the critical knowledge gaps, and providing a science-based framework for reversing declines before more species are pushed toward extinction."

Migratory birds are among the most visible and widespread components of global biodiversity. They help regulate insect populations, disperse seeds and pollinate plants, and support food webs across ecosystems and continents. They are also one of the primary ways people connect with nature, with millions of birdwatchers and community scientists around the world contributing observations to global databases that have become essential for understanding bird populations and informing conservation action.

Yet understanding exactly where and why populations are declining, and which of the world’s 11,000 bird species should be considered migratory, remains a challenge. Scientists are increasingly using advances in tracking technology, community science initiatives such as eBird, AI-enabled acoustic monitoring, and population modeling to identify migration routes, understand how populations are connected across seasons, and uncover the drivers of decline, including habitat loss, climate change, invasive species, collisions with buildings and infrastructure, disease, and pesticide use. The authors argue that reversing declines will require conservation strategies that address these threats across entire migratory lifecycles and international flyways rather than in isolation.

"Previous analyses have brought global attention to the fact that North American and European migratory birds are declining at alarming rates," said Nathan W. Cooper of Smithsonian’s National Zoo and Conservation Biology Institute and co-lead author of the study. “But, until now, we did not have a good assessment about how birds are doing across all of the global terrestrial and marine flyways.”

The review outlines a framework for reversing declines that includes expanding monitoring and scientific understanding, strengthening conservation social science, protecting critical habitats, reducing major threats, and increasing international cooperation. It calls for integrating ecological and social sciences to develop conservation solutions that are effective locally and scalable across countries, cultures, economies, and governance systems.

One example of this approach is Road to Recovery, a science-based initiative co-founded by Marra and now housed at Georgetown University. The initiative coordinates a hemispheric response to identify the factors limiting populations and implement targeted conservation actions before species become threatened by combining advances in science and technology with the human dimensions of species conservation.

The researchers stress that despite the concerning trends, species-focused conservation initiatives have a proven record of success. Past efforts have helped recover waterfowl, cranes, shorebirds, and raptors once on the brink of extinction. The challenge, they argue, is scaling those successes to match the geographic scope and complexity of migratory birds.

"These declines are not inevitable," Marra said. "We know conservation works. This review shows that we have the scientific knowledge needed to reverse many of these declines. The challenge now is bringing together the partnerships, resources, and political and public commitment to implement those solutions at the scale migratory birds require."

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Journal

Nature Reviews Biodiversity

DOI

10.1038/s44358-026-00177-7 

Method of Research

Literature review

Subject of Research

Animals

Article Title

Status, threats and conservation of Earth’s migratory birds

Article Publication Date

23-Jul-2026

 

Human impacts rewrite the rules of island biodiversity around the globe

New research provides the most comprehensive assessment to date of human influences on island biodiversity patterns.

University of Birmingham

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Lophopsittacus mauritianus is a large species of parrot that was formerly endemic to the island of Mauritius in the Indian Ocean. It went extinct in the 17th century, likely due to a combination of introduced species, habitat loss and hunting.

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Credit: Used with permission of Julian Hume.

A new study reveals that human activities have fundamentally reshaped biodiversity patterns on islands across the globe, providing important implications for how scientists understand ecology, evolution and conservation. 

Led by the University of Birmingham, the international team of researchers examined how species extinctions and introductions have transformed island ecosystems over a (?) millennia showing that islands have experienced a disproportionate share of global biodiversity loss.   

In total, island endemic species account for around 75% of recorded anthropogenic extinctions globally, while many islands have also received large numbers of introduced species. In some cases, the number of introduced species now equals or exceeds the original native flora and fauna. For example, in the Hawaiian Islands almost all endemic species of bird have been driven extinct, with roughly the same number having been introduced from elsewhere in the world. 

The study’s findings, published today (23 Jul) in Science Advances, also suggest that many biodiversity patterns observed today – such as species richness, endemism and ecological interactions – are not solely the result of natural ecological and evolutionary processes but also often reflect a long legacy of human influence.  

Key findings: 
 

• Key biodiversity patterns have been altered due to the impact of human-driven extinctions and introductions, which have changed fundamental relationships between biodiversity and different abiotic factors, such as island size and island isolation, and potentially affecting long-standing ecological and evolutionary theories.  
   

• In several cases, human impacts commenced thousands of years ago, making it increasingly difficult to tease apart natural patterns from human influences. 

 

• Introduced species often offset species losses numerically, but not ecologically. Many islands now have as many or more species than before human arrival due to introductions, yet they have still experienced substantial losses of native biodiversity and ecological function. 
   

• For certain groups – primarily birds and mammals – researchers have a reasonable idea of the biodiversity that has been lost on islands. However, for many others there is a lack of knowledge, making it difficult to identify pre-human biodiversity baselines and fully understand the extent to which island ecosystems have been altered.  
   

Dr Thomas J. Matthews, from the University of Birmingham and lead author of the study, said: "Islands have played a central role in the development of ecological and evolutionary theory. However, many of the biodiversity patterns we observe today have been shaped not only by natural processes but also by thousands of years of human-driven extinctions, species introductions and environmental change.  

"We know that these human actions have substantially affected island environments. What we show in this study is a different kind of impact - that human actions have also substantially altered our understanding of the natural world. Many current ecological and evolutionary patterns observed on islands reflect not just natural processes but also a legacy of human-induced change spanning millennia." 

Dr Sandra Nogué, ERC researcher at UAB and CREAF and co-author of the study, said: "Overall, we found that the extinction of endemic species, combined with the introduction of plants and animals that are widespread elsewhere in the world, is making islands increasingly homogeneous and more similar to one another." 

Islands have long been regarded as natural laboratories for understanding biodiversity, inspiring foundational scientific ideas such as Darwin's theory of evolution and the theory of island biogeography. However, this new review highlights how extensive historical changes to island ecosystems can affect our interpretation of these systems.   

The paper also highlights a range of existing and emerging approaches that can help scientists reconstruct pre-human biodiversity baselines. Approaches include fossil evidence, ancient DNA analysis, museum collections, historical records, and advanced ecological modelling. The team argues that combining these approaches will provide a more accurate understanding of how island biodiversity has changed through time. 

Dr Thomas J. Matthews added: "New datasets, analytical tools and palaeoecological evidence are giving us unprecedented opportunities to better understand the natural history of island ecosystems. By integrating these different sources of information, we can develop a clearer picture of how biodiversity patterns have been transformed as well as how the ways in which they might be restored or conserved in the future." 

Future biodiversity research must increasingly consider both natural and anthropogenic drivers of ecological change. As globalisation, trade and land-use change continue to influence island ecosystems, understanding the combined effects of natural and human processes will be essential for effective conservation planning. 

The study was led by the University of Birmingham and involved researchers from several international institutions, including CREAF, the Universitat Autònoma de Barcelona (UAB), the BETA Technological Centre (UVic-UCC), the Granollers Museum of Natural Sciences, the University of La Laguna and the Centre for Biodiversity and Global Change Research at the Autonomous University of Madrid. 

ENDS

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Journal

Science Advances

DOI

10.1126/sciadv.aee1788 

Method of Research

Literature review

Subject of Research

Animals

Article Title

Emergent patterns of island biodiversity in the Anthropocene

Article Publication Date

23-Jul-2026

 

Insect submariners survive the depths without imploding

University of British Columbia

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Excised Chaoborus edulis airsacs

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Credit: Philip Matthews

Deep-diving insect larvae are challenging a long-held idea about why there are no insects in the ocean, thanks to sturdy air sacs.

Daily dive to dodge death

In Lake Malawi in East Africa, billions of lake fly larvae (Chaoborus edulis), make an unusual commute: By day, they sink more than 200 metres into the lake’s oxygen-starved “dead zone” to hide from predators. By night, they rise to safely feed – but not before passing through a horde of waiting fish.

UBC researchers Drs. Philip Matthews and Evan McKenzie deployed a sonar system at the bottom of the lake to map these daily dives.

Dissecting the larvae, the team found they had turned part of their respiratory system into two pairs of tiny air sacs that function like ballast tanks to control their buoyancy.

They also found that the air sac wall contains a material called resilin which expands or contracts when the larvae change the wall’s pH. This mechanism allows the larvae to control the volume of their sacs and so, their own buoyancy. 

Under pressure

The researchers placed larvae in tiny pressure chambers to find the maximum depths they could endure before their air-sacs imploded.

They proved remarkably tough, holding out to the equivalent of more than 400 metres deep, far beyond the larvae’s daily dives.

Insects thrive on land and fresh water, but the open ocean is insect-free. One popular explanation is the insects’ air-filled respiratory systems would collapse under the pressure of the depths. These larvae puncture that idea.

pH-powered engines

Resilin has been studied in other insects as a nearly perfect biological rubber in wear-and-tear-resistant wing hinges and tendons.

In the future, the research could add to work aimed at creating pH-powered resilin smart materials or artificial muscles activated on chemical command.

This project was partially funded by Natural Sciences and Engineering Research Council of Canada Discovery and Accelerator grants

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Journal

Science

DOI

10.1126/science.aed0667 

Article Title

Crush-resistant air sacs allow insect larvae to exploit aquatic habitats at extreme depth

Article Publication Date

23-Jul-2026

Related News Releases

• Insect submariners survive the depths without imploding
  (University of British Columbia)

Chaoborus edulis larva Credit Philip Matthews

A swarm of the lake fly larvae, Chaoborus edulis, over Lake Malawi

 

Recovery of the sonar device in Lake Malawi

Chaoborus edulis larvae close up Credit Philip Matthews [VIDEO] 

Chaoborus edulis air sac imploding [VIDEO] 

A micro CT scan of the larva showing the air sacs in situ [VIDEO]