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The oldest outdoor swimming pool in the UK – the Grade II listed Cleveland Pools in Bath which first opened in 1815 – will reopen during the summer of 2023, after significant restoration. With a new 50-metre outdoor pool having opened in Brighton) in June and a council-funded restoration under way in Hull, the simple pleasure of the public outdoor pool is seeing a return to popularity to the UK.
In the early 20th century, an explosion of new outdoor pools opened across Britain. Taking the name “lido” from the Italian word for coastline, the boom of construction in the 20th century was part of the post-war public works programme, which aimed to create jobs and promote health. While indoor pools had been gender segregated, public lidos were deliberately mixed and became synonymous with fun and socialising.
Lidos at coastal towns such as Scarborough and Blackpool were destinations for residents and tourists. Lido design between the 1920s and 1940s was innovative and drawn from exotic sources, such as European resorts and cruise ships. They incorporated sumptuous sundecks, sophisticated outdoor restaurants and cafes, alongside vast inviting bathing areas. Impressive diving boards challenged those brave enough to leap theatrically and please the crowds. These lidos were able to accommodate thousands of visitors as wholesome, accessible leisure destinations.
Some of the most iconic lidos are the magnificent art deco sites in Saltdean, Plymouth and Penzance in the south of England. These stunning sites have thankfully been saved from demolition, many others were not. Lido lovers remain hopeful that another art deco site, Broomhill in Ipswich, will one day be restored.
Lidos were grand constructions and monuments of civic pride, both for those who created them and for those who frequented them. They reflected times of change in society and great optimism. At their peak, there were more than 300 active public outdoor pools in the UK, with 11 in Liverpool and 68 in London.
The 1960 Wolfenden report, Sport and the Community and the 1968 Sports Council report Planning for Sport were catalysts for the demise of outdoor swimming pools in policy. The mandate was that “as a general rule, [pools] should be indoors”.
Lidos fell into disrepair and were steadily replaced or destroyed, after councils no longer saw them as part of their leisure facilities and reduced or stopped funding. At the turn of the century, only around 130 public outdoor pools remained, predominately in the south of the UK. That number hardly changed in the following two decades.
The steady loss of these lidos didn’t go unnoticed. The Thirties Society’s report Farewell my Lido (1991) and then Janet Smith’s important 2005 English Heritage-funded book Liquid Assets (with a forthright foreword from artist Tracey Emin) document the history and argued passionately for a brighter future for these much-loved public luxuries.
But as local councils faced financial crises in 2008 and central government reduced spending further from 2010, leisure was treated differently. Responsibility for lidos was transferred to charitable trusts. Those that remained were preserved and saved by community groups or trusts and some local authorities, who understood their public value.
During the last two decades – and recently accelerated by the COVID-19 pandemic where outdoor swimming was one of the few activities allowed for a while – there has been a steady growth in outdoor, wild and lido swimming.
And there are cultural markers of a resurgence, too. Fashion label Radley created a limited-edition lido handbag in 2016. In 2019, crowdfunding helped create The Lido Guide. The same year, a heart-warming novel, The Lido by Libby Page, beautifully captured the community spirit, history and value of lidos.
Photographer Christopher Beanland paid homage to lidos in 2020 through a global collection of outdoor pools and their stories. And then this year, Brit Pop band Blur choose the iconic 2014 Martin Parr image of a solitary swimmer in Gourock Pool for the cover of their upcoming album, The Ballad of Darren.
Over 30 lido schemes have emerged from 2021 onwards. They’ve been nurtured by the Future Lidos Group and their National Heritage Lottery funded pooling resources project. The design emphasis is once again on innovation, taking the lessons of lido heritage and the human connection which formed in these inclusive sites into consideration.
If Sport England’s policies can recognise the diverse value of lidos to public health and leisure, the next decade could see a further resurgence in restorations. Even more lidos could soon be making a welcome return across Britain, allowing more access to outdoor swimming – whatever the weather.
Michael Wood founded the Future Lidos Group in 2021 and is a volunteer on the steering committee for the Pooling Resources project. The Pooling Resources project received funding from National Heritage Lottery Fund in January 2023 to create a toolkit to support the restoration and creation of lidos. He has been a volunteer with the Friends of Tynemouth Outdoor Pool for 9 years. He has not personally received any fees for any of this work.
The Antarctic Ice Sheet, which covers an area greater than the US and Mexico combined, holds enough water to raise global sea level by more than 57 metres if melted completely. This would flood hundreds of cities worldwide. And evidence suggests it is melting fast. Satellite observations have revealed that grounded ice (ice that is in contact with the bed beneath it) in coastal areas of West Antarctica has been lost at a rate of up to 30 metres per day in recent years.
But the satellite record of ice sheet change is relatively short as there are only 50 years’ worth of observations. This limits our understanding of how ice sheets have evolved over longer periods of time, including the maximum speed at which they can retreat and the parts that are most vulnerable to melting.
So, we set out to investigate how ice sheets responded during a previous period of climatic warming – the last “deglaciation”. This climate shift occurred between roughly 20,000 and 11,000 years ago and spanned Earth’s transition from a glacial period, when ice sheets covered large parts of Europe and North America, to the period in which we currently live (called the Holocene interglacial period).
During the last deglaciation, rates of temperature and sea-level rise were broadly comparable to today. So, studying the changes to ice sheets in this period has allowed us to estimate how Earth’s two remaining ice sheets (Greenland and Antarctica) might respond to an even warmer climate in the future.
Our recently published results show that ice sheets are capable of retreating in bursts of up to 600 metres per day. This is much faster than has been observed so far from space.
Our research used high-resolution maps of the Norwegian seafloor to identify small landforms called “corrugation ridges”. These 1–2 metre high ridges were produced when a former ice sheet retreated during the last deglaciation.
Tides lifted the ice sheet up and down. At low tide, the ice sheet rested on the seafloor, which pushed the sediment at the edge of the ice sheet upwards into ridges. Given that there are two low tides each day off Norway, two separate ridges were produced daily. Measuring the space between these ridges enabled us to calculate the pace of the ice sheet’s retreat.
During the last deglaciation, the Scandinavian Ice Sheet that we studied underwent pulses of extremely rapid retreat – at rates between 50 and 600 metres per day. These rates are up to 20 times faster than the highest rate of ice sheet retreat that has so far been measured in Antarctica from satellites.
The highest rates of ice sheet retreat occurred across the flattest areas of the ice sheet’s bed. In flat-bedded areas, only a relatively small amount of melting, of around half a metre per day, is required to instigate a pulse of rapid retreat. Ice sheets in these regions are very lightly attached to their beds and therefore require only minimal amounts of melting to become fully buoyant, which can result in almost instantaneous retreat.
However, rapid “buoyancy-driven” retreat such as this is probably only sustained over short periods of time – from days to months – before a change in the ice sheet bed or ice surface slope farther inland puts the brakes on retreat. This demonstrates how nonlinear, or “pulsed”, the nature of ice sheet retreat was in the past.
This will likely also be the case in the future.
Our findings reveal how quickly ice sheets are capable of retreating during periods of climate warming. We suggest that pulses of very rapid retreat, from tens to hundreds of metres per day, could take place across flat-bedded parts of the Antarctic Ice Sheet even under current rates of melting.
This has implications for the vast and potentially unstable Thwaites Glacier of West Antarctica. Since scientists began observing ice sheet changes via satellites, Thwaites Glacier has experienced considerable retreat and is now only 4km away from a flat area of its bed. Thwaites Glacier could therefore suffer pulses of rapid retreat in the near future.
Ice losses resulting from retreat across this flat region could accelerate the rate at which ice in the rest of the Thwaites drainage basin collapses into the ocean. The Thwaites drainage basin contains enough ice to raise global sea levels by approximately 65cm.
Our results shed new light on how ice sheets interact with their beds over different timescales. High rates of retreat can occur over decades to centuries where the bed of an ice sheet deepens inland. But we found that ice sheets on flat regions are most vulnerable to extremely rapid retreat over much shorter timescales.
Together with data about the shape of ice sheet beds, incorporating this short-term mechanism of retreat into computer simulations will be critical for accurately predicting rates of ice sheet change and sea-level rise in the future.
Frazer Christie receives funding from the Prince Albert II of Monaco Foundation.
Christine Batchelor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Seals, sea lions and walruses – a group of animals called pinnipeds – have been heavily exploited throughout much of human history. Many of these species have at some point even been threatened with extinction.
But, in the UK, their decline has largely been reversed. Since the Conservation of Seals Act 1970 prohibited the killing or injuring of grey and harbour seals around the UK, the number of grey seals in the country has doubled to 157,000 – although there seems to be significant regional variation. More than one-third of the world’s grey seals now populate the UK’s waters.
This is excellent news for seal conservation. But it can be problematic for the fishing industry, which now faces an increase in damage to catch and gear inflicted by seals. Understanding how seal populations are changing will help manage their interactions with fisheries and other marine industries.
Grey seals and other pinnipeds are intelligent and highly adaptable creatures, able to switch their prey and foraging habits to suit their environment. But the threats these species face are changing fast. Slow to reproduce and vulnerable to climate change and disease, these now common animals could become threatened in the future should conditions continue to change.
The population expansion of UK grey seals is probably the result of several factors.
In the decade that followed the Conservation of Seals Act, rising populations may have been the result of a lack of hunting or managed culls. Culls were carried out at some grey seal sites in the 1970s, but not as blanket attempts to control the overall population.
But since then, population increases may instead be due to changes in food availability. In the absence of other sources of mortality, food availability often drives population expansion. And grey seals are opportunistic foragers that feed on whichever prey is easiest to catch.
Several studies have looked at how grey seal diets have changed over the past few decades. By examining the hard parts that remain in seal faeces such as bones and shells, it is possible to reconstruct their prey. This technique underreports some food groups such as salmonids, but is currently the only method that allows scientists to quantify a seal’s diet.
In three separate years (1985, 2002 and 2010), seal faeces were collected in coastal areas of Scotland and eastern England. Seal diets consisted of 66 different species, showcasing their ability to exploit whatever prey becomes available.
When large fish are absent, they hunt smaller prey such as sandeels. But, as populations of larger prey species such as herring, cod and whiting increase, they exploit this too.
Grey seals, and other pinnipeds, inhabit a dynamic environment and the threats they face are changing rapidly. Climate change, for example, is affecting local food composition and abundance.
One of the main ways this occurs is through a process called “tropicalisation”, where rising sea temperatures cause warm water species to replace species that live in cooler waters. On average, marine species are shifting polewards at a rate of 72km per decade.
Seals are also vulnerable to population shocks. Pinnipeds have a long lifespan and tend to have small numbers of offspring – usually only one pup per year. Any environmental change that is short-lived can be buffered by seals’ longevity. If they don’t successfully pup one year, then they are likely to do so the next.
But any increase in adult mortality can quickly affect a population. Seal populations are therefore particularly vulnerable to diseases and other sources of adult mortality.
Respiratory diseases have a particularly acute impact on the foraging ability of diving animals such as seals. What could be a relatively minor threat to an animal that lives on land, could be life-threatening to one that dives. For example, more than 3,000 sea lions were found dead or dying on Peru’s coast following an outbreak of influenza in January 2023. Over 1,000 sea lions died on just one island, Isla San Gallan.
Climate change is likely to increase the risk of disease in the future. Research finds that warmer conditions favour pathogen development, survival and spread.
The way that humans use the sea is also changing. Offshore wind, for example, is projected to supply around one-third of the UK’s electricity generation by 2030. But, the construction, operation and maintenance of offshore wind farms causes noise disturbance and may change the behaviour of marine animals.
Research on harbour seals found that they tend to avoid areas where piling activity (the process of driving foundations into the seabed) is ongoing. Where piling is occurring, seals use of the area was found to decrease by 83%.
But offshore wind infrastructure can also lead to the development of artificial reefs. These reefs may result in an increased density of prey in the surrounding area and could improve foraging opportunities. Whether ocean infrastructure such as this will benefit seals depends on if it supports an increase in prey populations across a region – or simply concentrates existing populations in a smaller area.
Grey seals are the top marine predator in UK waters and seem to have become more common since the 1980s. But their situation remains precarious and they have little buffer should conditions change. This vulnerability highlights the importance of understanding the impact of future threats including climate change, more renewable energy infrastructure and disease outbreak.
Katrina Davis receives funding from the John Fell Oxford University Press Research Fund.
Richard Bevan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Electoral reforms proposed by the Mexican government have sparked huge protests across the country. Hundreds of thousands of people took to the streets in more than 100 towns and cities in opposition to legislation passed by the government of Andrés Manuel López Obrador. The reform will slash funding to the country’s electoral authority, which critics say undermine its independence and ability to organise elections.
Most protesters were dressed in pink and white, the colours of the National Electoral Institute (INE). They are attacking the reforms as unconstitutional and designed to make electoral scrutiny less effective while also making it harder to register to vote in more remote areas. The new law passed the senate on February 22 by 72 votes to 50.
López Obrador is justifying the reforms on cost grounds. Mexico’s elections are among the most expensive in the world. The president has long criticised the INE for the size of its permanent bureaucracy and its high salaries for officials, which its supporters believe is necessary to ensure qualified and loyal staff.
The INE is seen as particularly important in Mexico where elections have previously been questioned for a perceived lack of transparency in this young democracy. It’s important to remember that Mexico had an authoritarian regime led by the Party of the Institutionalised Revolution (PRI) between 1929 and 2000.
During the authoritarian period, elections took place periodically, but were undemocratic due to fraud and coercion. The PRI controlled the presidency from 1929 until 2000 and, until the late 1980s, most elected government offices. The PRI managed its factions and the flawed and corrupt electoral system ensured that the leadership could keep elites happy by ensuring them victory.
So the establishment of a powerful, independent body to manage Mexico’s electoral system with no political interference has been central to the country’s transition to democracy. As a result, many Mexicans are fiercely protective of the INE and see López Obrador’s reforms as no less than interfering with democracy itself.
There are two issues with the reform. The first is procedural: it was not negotiated with the main opposition parties, as past reforms had been, and it was not discussed fully following the usual legislative process in Congress. The second is its content and effects on INE. The reform limits INE’s ability to perform its duties, by changing its structure and legal power to keep political parties and candidates accountable.
Since 2014 INE has been responsible of organising all elections in the country. Mexico operates a federal system including 32 states, the capital city and 2,471 municipalities. Mexicans vote at the federal, state and municipal levels. Elections take place every year at some level.
In 2024, Mexicans will vote for the president, federal deputies, senators, nine governors and legislators in 30 states. The process will require 150,000 polling stations across the country.
The structure of the INE is complex. It has 32 executive boards at state level and 300 executive boards at district level. López Obrador’s reform cuts the number of electoral civil servants in the state board from five to three, and in the local board from five to one.
These staff are responsible for organising elections: setting up polling stations and recruiting and training people to run those polling stations during elections. INE local staff must also manage and update the voting register. It has been estimated that the reforms will cut the number of INE staff by 85%.
The other major criticism of the reform is that it is these local INE boards which administer voter identification cards, which are seen by most Mexicans as their main form of identification. The reform will cut the number of offices issuing these cards and relocating them from their own offices into schools, health centres and other government buildings.
There are concerns that these venues will lack the security infrastructure to protect this information. And moving INE offices to these venues risks undermining their independence – or, equally as important, the public perception of their independence.
Mexicans living abroad (principally in the US), who previously obtained their ID through a special arrangement between the INE and the ministry for foreign affairs will now vote with their passport or consular identification. This will cut the independent INE out, further undermining the credibility of the process.
The INE also oversees campaign spending with the power to disqualify non-compliant candidates – as it did with two candidates from the president’s party, Morena in 2021. The latest reform, which also reduces the maximum penalty for irregularities to a fine, will make it more difficult for the INE to investigate and adjudicate such cases.
Opponents to the reform have asked the Supreme Court on its constitutionality. Justice Alberto Pérez Dayán has suspended its application for two state elections taking place this year. López Obrador has hit back with criticism of the judge and his ruling.
He also recently accused the supreme court’s chief justice Norma Piña – the first woman to hold the post – of presiding over a “wave of rulings in favour of criminal suspects”, in a statement that is widely seen as an attempt to undermine the court’s authority.
López Obrador currently enjoys high levels of popularity and Morena’s prospects in the 2024 election are seen as very favourable, so it seems counter-intuitive to introduce reforms which effectively undermine the electoral authority. It remains to be seen whether the public outrage over this electoral reform will affect his own approval rating.
Rosario Aguilar worked at IFE between September 2000 and June 2001. She was co-PI of the Mexican National Election Study in 2012 and 2015 that received funding from INE and Conacyt.
Russia’s war in Ukraine has quickly refocused the politics of its Baltic neighbours. Renewed threats to national security have swiftly risen to the top of each nation’s priorities.
In autumn 2022, Estonia like other Baltic countries, restricted travel over its land borders from Russia. Flights were already banned from Russia as part of an EU-wide decision. St Petersburg is only 229 miles away from Estonia’s capital Tallinn, and Estonians are all too aware of their recent history with Russia including being conquered by the Russian empire from 1710 and forced to become part of the Soviet Union in the 20th century. It shares memories of Russification and suppression of its language with Ukraine.
Occupied by the Soviet Union until 1991 and sharing a 294km border with Russia, defence and security have risen up the agenda in the Estonian media and politics in the past 12 months. But it’s not surprising with a militarised Russia on its doorstep the Ukraine war is focusing minds in the election of the country’s next parliament. Estonia is providing more military aid as a share of GDP than any other Nato country. Polls close on March 5 2023. National defence, crisis readiness and energy independence are all being covered in the campaigns.
Tensions are clear. Russia expelled Estonia’s ambassador Margus Laidre in January 2023 and Estonia responded by doing the same to the Russian ambassador Vladimir Lipajev. Just days before the election Estonia held a 105th anniversary parade of the Republic of Estonia in Tallinn’s Freedom Square. The highly symbolic event also featured military equipment and representation from Estonia’s Nato allies and a speech from Nato secretary general Jens Stoltenberg, who evoked Estonia’s fight for freedom and the Ukrainian battle with Russia today. He said: “Your history is a strong reminder that we cannot take our freedom for granted.”
The first televised debate of this election produced by the Estonian Public Broadcasting Service focused, not surprisingly given the international situation, on defence.
Estonia’s political parties seem to widely agree on security and defence policies. A cross-party consensus is committed to increasing national defence spending, with most parties pledging to bring defence spending to a minimum of 3% GDP. The radical right populist Estonian Conservative People’s party (EKRE) is, however, critical of the current government’s decision to give Ukraine weapons and ammunition, which it claimed had depleted Estonia’s defences. And one prominent EKRE parliamentary candidate has called for a change of policy to establish better relations with Russia.
There is little disagreement over Estonia’s continued Nato membership or a pledge to invest in national crisis infrastructure (such as bomb shelters and emergency sirens), issues that have not received much attention in previous election manifestos.
Read more: Ukraine war is blurring the lines between Nato and the EU on defence policy
Putin’s war in Ukraine and the consequent energy crisis has also highlighted the importance of energy policy, and all parties directly link the issue to national defence. While there is broad agreement across parties about the need to ensure electric energy independence by 2030, the ways in which to reach that vary by party and ideology. The liberal and centre-left parties emphasise renewable energy sources as the primary route to energy independence in their manifestos and public debates, right-wing EKRE openly opposes the “mad green turn” and pledges to continue fossil fuels use until Estonia transitions to nuclear energy.
Despite the widespread agreement on defence, electoral research suggests that parties can still compete on issues that they primarily agree on by emphasising their competence and ability to manage the issue. The latest polls suggest that current prime minister Kaja Kallas, and her Reform Party, lead this competence battle and are set to win the most votes in the election.
Kallas, the first female prime minister of Estonia, enjoys a healthy lead as the most popular potential leader. She is an avid and vocal supporter of Ukraine, and public satisfaction with Kallas and her government has increased rapidly following the start of Russia’s full-scale armed offensive in Ukraine in February 2022.
Overall, her current support reflects an impressive turnaround as her popularity had dropped to all-time low of 16% in November 2021, when her government was perceived as indecisive in its handling of COVID-19 pandemic.
Kallas is regularly seen in leading western news outlets such as the New York Times, Der Spiegel, The Times. She now enjoys high approval ratings at home for her strong stance on Putin, effectively subverting common gender stereotypes of women being weak on national defence and security issues.
Nationalistic right-wing conservative parties including EKRE and Pro Patria are strongly emphasising their credentials in defending the Estonian language, culture and sustainability as a nation. Notably, EKRE avoids mentioning Ukraine or Ukrainian refugees in their manifesto, and instead emphasises the need to stop mass migration to Estonia.
Pro Patria and EKRE, and the liberal right-wing Reform party also use the current security situation to highlight nationalistic credentials. These parties pledge to remove the right to vote in local elections for Russian citizens who are permanent residents in Estonia. The Centre party, which currently has the largest support among Russian-speaking voters, and left-liberal Estonian Social Democrats both pledge to respect local election voting rights for all permanent residents.
With a 23.7% ethnic Russian minority, Estonia currently provides early and general education both in Estonian and Russian, in schools separated by language. The Ukraine war has brought this policy further up the agenda with most parties now pledging to create a unified school system with all or most classes taught in Estonian, with the exception of the Centre party.
The looming presence of the Russian war in Ukraine has far-reaching implications for Estonia and its neighbours. The threats created by a nearby war have further strengthened its hardline attitude towards Russia as Estonia, the other Baltic countries and Poland see (and fear) more than most what could happen next. There’s no question that this will stay at the top of the agenda for whoever takes over as prime minister.
Zachary Greene receives funding from the Norface Network as part of the EU-in-Action research project and the EU Horizon 2020 OPTED project, designing infrastructure for computational text analysis in the social sciences.
Maarja Lühiste does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
When we think of what makes athletes great, few of us would think that sleep might play an important role. But many of the world’s best athletes say sleep is an essential part of their training routine and key in helping them to perform well.
Serena Williams, for example, strives to get eight hours of sleep each night. NBA star LeBron James aims for eight to ten hours per night, while NFL legend Tom Brady says he goes to bed early and gets at least nine hours of sleep.
It’s no wonder, since sleep plays a key role in metabolism, the growth and repair of tissues (such as our muscles), and ensures memory, reaction time and decision making are all working optimally. All these processes impact sporting performance.
But it isn’t just athletes whose athletic performance can benefit from proper sleep. Even amateur gym-goers can maximise the benefits of exercise for their fitness and health by getting enough good sleep each night.
Here are just some of the ways sleep benefits your fitness:
Exercise is great for improving aerobic fitness. It improves both aerobic capacity (being able to run or cycle faster with a heavier load) and efficiency (meaning your body requires less oxygen to run or cycle at the same pace).
One contributing factor to improved aerobic fitness is the function of the body’s mitochondria. Mitochondria are small structures within the cells of the muscles that are responsible for creating the energy the muscle requires during exercise.
Research shows that poor sleep (getting only four hours a night for five nights) can reduce the function of mitochondria in healthy participants. High-intensity interval training was shown to alleviate these impairments in the short-term (over a five-day period). But, it’s currently unclear how these impairments would influence adaptations to exercise in the longer term, so it’s best to get a good night’s sleep if improving aerobic fitness is one of your goals.
Sleep is also important if you’re looking to build strength or muscle.
Muscle growth occurs when new proteins are added to the muscle structure – a process known as “muscle protein synthesis”. This process is stimulated by exercise and food (specifically protein) intake, and can last at least 24 hours after a workout.
Research shows that even just a few nights of insufficient sleep reduces the muscle protein synthesis response to nutrient intake. This suggests that poor sleep may make it harder for the body to build muscle.
Hormones act as chemical messengers that contribute to a range of functions throughout the body, such growth and development of tissues. Hormones which are involved with these building processes can be termed “anabolic” hormones.
Two anabolic hormones – testosterone and growth hormone, which are released during sleep – may also be important for recovery from and adaptation to exercise. These hormones have multiple roles in the body, and are linked to improved body composition (lower body fat and higher muscle mass). A higher amount of muscle mass and lower body fat can be beneficial for exercise and health.
When sleep is restricted to only five hours per night (similar to the amount of sleep many working adults get), testosterone levels are reduced in healthy young men. Sleep restriction of a similar duration also alters the release of growth hormone during sleep. While more research is needed, there’s a potential that these hormones may play a role in mediating the relationship between sleep and fitness, due to their link to improved body composition.
Exercise often uses glucose (sugar) as a fuel source. Muscles store glucose from the foods we eat in the form of glycogen to meet the demands of exercise. Replenishing glycogen stores after exercise is a key part of the recovery process. It can take up to 24 hours to fully replenish stores, with the correct nutrient intake. The hormone insulin can be needed for muscles to absorb glucose in order to make glycogen.
Numerous studies show that insufficient sleep reduces the effectiveness of insulin. This could impact on the body’s ability to replace glycogen stores, with one study revealing reduced muscle glycogen stores after a night of sleep deprivation.
Depleted glycogen stores can impair subsequent exercise performance in the short and long term, so it is important to ensure glycogen stores are replenished after exercise.
Sleep is clearly important for your fitness, so here are some ways to ensure you get proper sleep each night:
If you are trying to improve your fitness make sure you’re getting enough good quality sleep – aim for at least seven to nine hours of sleep each night.
Emma Sweeney has previously received funding from the Waterloo Foundation.
Ian Walshe does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Seagrasses are flowering plants that form dense underwater meadows in coastal waters worldwide, from the frigid seas of the Arctic to the warm shallows of the Caribbean. These meadows provide a refuge for young fish, food for grazing sea turtles and manatees, and help to slow climate change by absorbing carbon from the atmosphere up to 35 times faster than rainforests.
In a new study, we discovered another reason to preserve the world’s remaining seagrass meadows: they can build and maintain coral reef islands.
Throughout the tropics, the breakdown of shells and skeletons belonging to organisms living on coral reefs has produced enough sand to form entire islands. These coral reef islands are inhabited by over 700,000 people globally in nations including Kiribati, the Marshall Islands and the Maldives. Our research showed that seagrass meadows can make the right type of sand for building and maintaining the shorelines of these islands. This sand could help protect them from sea-level rise, which threatens the existence of low-lying nations.
Islands in the Maldives are primarily built from coral, but rising sea temperatures have caused reefs to bleach in recent years, which can kill corals. Seagrass may be vital for building and maintaining these islands in the future if reefs are lost to climate change.
If you are ever lucky enough to swim in a tropical seagrass meadow, take a close look at the leaves. You may notice that, instead of being completely smooth and green, there are what look like white grains of sand stuck to their surface.
A microscope reveals that these white grains are in fact tiny plants and animals. These creatures – scientists call them seagrass epibonts – are made of calcium carbonate and can include sea snails, single-celled foraminifera, crusts of coralline algae and colonies of invertebrates called bryozoans.
Some epibionts fall off the leaves or are whisked away when the seagrass dies to be deposited with other sediment on nearby islands. Over time, this accumulation helps to build and maintain the island shorelines. In our study, we aimed to find out how much sand was produced by organisms living in a seagrass meadow in the southern Maldives.
We used satellite images to map the density of seagrass and counted the leaves by randomly placing grids on the seafloor. We repeated this process 300 times, counting 27,528 individual seagrass leaves – not how most visitors to the Maldives spend their trip.
We collected 400 leaves and analysed them in a laboratory to work out the mass of epibionts living on them. The sand samples we collected from the meadow indicated how many of these organisms were the right size for building an island (between 0.063 and 2mm).
The rate at which different parts of the meadow produced sand-sized grains ranged from 0.22 to 0.86kg per square metre per year. Across the 1.1 square kilometres of seagrass meadow we studied, total annual sediment production was 762,000kg, with 482,000kg of this being the right size for island-building.
The volume of sand-sized sediment produced across the meadow would be large enough to build the neighbouring island of Faathihutta in just 18 years. Not all of this sand will go on to build islands – some will remain in the ocean. Nonetheless, this is a huge volume of sand being produced near islands in desperate need of sediment to bolster shorelines threatened by rising seas.
Reef island nations will need to protect seagrass meadows and aid their recovery in areas where they have been damaged. Another challenge will be ensuring that the movement of sand from seagrass meadows to islands is not obstructed by sea walls, harbours or jetties.
The societal benefits of seagrass meadows remain underappreciated. In the Maldives, seagrass is often removed from tourist resorts to meet visitor expectations of pristine white sands. This is a misconception of what the shallow waters around tropical islands are supposed to look like – and one that deprives visitors of the wide variety of marine life that call seagrass meadows home, such as schools of baby fish, seahorses and turtles.
Tourists should now also be aware that the very survival of the coral reef islands may depend on the sand that these seagrass meadows produce.
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Holly East receives funding from the British Society for Geomorphology.
Jamie Johnson does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
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