Most of us already know that getting enough sleep on the reg can reduce heart attack risk, make you more likely to exercise, and even help you live longer.

But working out exactly why that might be can prove difficult. In recent years, scientists have been looking more closely at the biological mechanisms behind sleep’s benefits.

And recently, a new paper published in the journal Cell identified a deep sleep circuit that might play a role in building muscle and improving our brain function.

The researchers discovered a feedback system that keeps certain hormones in check during sleep, too.

We’ve known for a long time that growth hormone, which is linked to stronger cartilage, muscle, and bone and an improved metabolism alongside a potentially lower heart disease and diabetes risk, is produced during sleep.

But we weren’t really sure how it was released.

In this paper, researchers looked at the brains of mice. They found that growth hormone-releasing hormone (GRGH) and somatostatin, which can suppress the hormone, both rise during rapid eye movement (REM) sleep. That leads to a greater overall release of growth hormone.

During other parts of sleep, though, somatostatin dips while GRGH only rises a little.

Additionally, the scientists found a feedback mechanism in a part of the brain called the locus coeruleus, part of the brain associated with attention, sleep-wake cycles, and thinking.

When growth hormone slowly builds up during sleep, it begins to wake us up bu stimulating this brain region, the study found. But when a more sudden influx of the hormone comes, it seems to make us sleepier.

“This suggests that sleep and growth hormone form a tightly balanced system: Too little sleep reduces growth hormone release, and too much growth hormone can in turn push the brain toward wakefulness,” study co-author Dr Daniel Silverman said.

“Sleep drives growth hormone release, and growth hormone feeds back to regulate wakefulness, and this balance is essential for growth, repair and metabolic health.”

The hormone’s interaction with our locus coeruleus, which keeps us attentive and alert, might also explain sleep’s cognitive benefits, he added.

“Growth hormone not only helps you build your muscle and bones and reduce your fat tissue, but may also have cognitive benefits, promoting your overall arousal level when you wake up.”

Researchers hope these findings can inform future therapies.

“Understanding the neural circuit for growth hormone release could eventually point toward new hormonal therapies to improve sleep quality or restore normal growth hormone balance,” Dr Silverman stated.

“There are some experimental gene therapies where you target a specific cell type. This circuit could be a novel handle to try to dial back the excitability of the locus coeruleus, which hasn’t been talked about before.”

As soon as it was revealed that Christopher Nolan would be following up his Oscar-winning historical biopic Oppenheimer with a new adaptation of the classic tome, The Odyssey, it was pretty obvious that we were in for another bum-numbing epic from the British director.

Nolan is already known for not shying away from a long runtime with his big-screen offerings, with some of his biggest films clocking in at long after the two-hour mark.

Inception, for example, lasts a total of 148 minutes, with Tenet beating that by two minutes.

Another of his most popular movies, Interstellar, lasts just shy of three hours at 169 minutes, while his latest film, Oppenheimer, ran for three hours exactly.

So, how will The Odyssey compare?

The good news for anyone worried about whether they’re going to need bathroom and snack breaks when planning their cinema trip for The Odyssey is that the film isn’t quite as long as Oppenheimer.

However, it has to be said that it’s still one of Nolan’s longest movies to date, at 172 minutes in total, as reported by Ireland’s official film classification body, the IFCO.

Of course, it’s understandable that The Odyssey would be a long one, considering how much material there is for Nolan to condense into one film.

Based on Homer’s Greek epic, the original story centres around Odysseus and his mammoth journey home to his wife and son in Ithaca at the end of the Trojan war, where along the way he has to face adversaries from mythology like the cyclops and sirens.

Matt Damon will take the lead as Odysseus in the new film adaptation of the tale, sharing the screen with everyone from Anne Hathaway, Robert Pattinson and Tom Holland to Zendaya, Lupita Nyong’o and Charlize Theron.

The Odyssey is due to hit cinemas on Friday 17 July. Check out our more in-depth guide to the new Nolan film here.

Harry Styles took a moment to pay tribute to his former One Direction bandmates after wrapping up his epic, record-breaking run of shows at Wembley Stadium over the weekend.

On Sunday night, the chart-topping star delivered the 12th and final Wembley Stadium gigon his Together, Together world tour, off the back of his hit album Kiss All The Time. Disco, Occasionally.

During his London shows, Harry has been taking a moment to reflect on the early stages of his career, which was also the case during Sunday night’s concert.

“I wouldn’t be on this stage if it wasn’t for four friends of mine that were a massive part of this journey,” he told the crowd, before publicly thanking Niall Horan, Louis Tomlinson, Zayn Malik and his “dear friend”, the late Liam Payne “for these nights and everything that I learned in this time, the friendship, everything”.

“None of this would be possible, I wouldn’t be here without you, thank you so much,” he added.

Liam died in October 2024 at the age of 31, after falling from the balcony of a hotel where he was staying in Argentina, while under the influence of numerous substances.

In the days that followed, the four remaining members of One Direction issued a joint statement, which read: “The memories we shared with [Liam] will be treasured forever. For now, our thoughts are with his family, his friends, and the fans who loved him alongside us. We will miss him terribly. We love you Liam.”

They then posted more personal tributes on their individual social media accounts, with Harry remembering his “lovely friend” as “warm, supportive and incredibly loving”.

Harry lamented: “The years we spent together will forever remain among the most cherished years of my life. I will miss him always.”

More recently, Harry admitted that Liam’s death was something he has “struggled” to address over the last two years.

“There was a period when he passed away where I really struggled with kind of acknowledging how strange it is to have people kind of own part of your grief, in a way,” the Sign Of The Times singer shared.

“I [had] such strong feelings around my friend passing away, and then suddenly, being aware [that] there [was] maybe a desire from other people [for] you to convey that in some way – or it means you’re not feeling what you’re feeling or something.”

The Grammy winner added: “It’s so difficult to lose a friend. It’s difficult to lose any friend, but it’s so difficult to lose a friend who is so like you in so many ways. It’s like, I saw [in Liam] someone with the kindest heart, who just wanted to be great.”

Keir Starmer is preparing for a dressing down from Donald Trump at his last Nato summit as prime minister over the government’s underwhelming defence spending plans.

The PM will fly to Ankara in Turkey a week after unveiling the long-delayed Defence Investment Plan (DIP).

Although it contained an extra £15 billion for the armed forces over the next four years, nearly one-third of it is unfunded, while there was no pathway for how the government plans to hit its target of spending 3.5% of national income on defence by 2035.

Starmer insisted that, once security spending is added, Britain will be spending 4.2% of its gross domestic product (GDP) on defence by then.

But that would still fall short of Trump’s demand that all Nato allies increase defence-related spending to 5% of GDP by the middle of the next decade.

It’s therefore no surprise that, judging by his social media posts, the US president may already sharpening his knives as he prepares to meet the outgoing prime minister.

Trump reposted a tweet on his platform, Truth Social, over the weekend which attacked England’s supposed decline.

“Just 100 years ago, England was the greatest empire the world had ever seen,” the post, from an account called Geiger Capital, read.

“A few generations later, they are a deindustrialized welfare zone unable to stop third-world men from invading on rubber boats.

“Decline happens fast. Weak leaders and suicidal empathy.”

The same post also pointed out that Britain is on the cusp of appointing its seventh prime minister in a decade, with Andy Burnham preparing to replace Starmer in two weeks’ time.

Trump’s dig comes after months of turmoil in the UK-US relationship, triggered by Starmer’s refusal to let American troops use British military base to launch attacks on Iran.

Trump has already criticised the incoming PM too, describing Burnham – the former mayor of Greater Manchester – as “the mayor of a town” and “extremely liberal”.

The US ambassador to Nato Matthew Whitaker, has already hinted that the US president will be cracking the whip on his allies at the summit in Turkey this week.

In a thinly-veiled threat, he said: “Some allies are doing more than others.

“Poland, the North countries, the Baltic countries lead the way and Germany is on track for the 5%, reaching it in 2029, but many allies are lagging behind and President Trump expects all allies to step up immediately.

“We expect all allies to demonstrate meaningful upward trajectories both quantitively and qualitatively in defence spending that results in fairer burden sharing.”

Britain was Nato’s third largest defence spender in 2015 after the US and Greece, but last year it slipped down to 12th.

Burnham has vowed to “take my responsibilities fully” to fund the DIP if he gets into office.

Listen to Commons People, the podcast that makes politics easy. Every week, Kevin Schofield and Kate Nicholson unpack the week’s biggest stories to keep you informed. Join us for straightforward analysis of what’s going on at Westminster.

Anyone with even a passing interest in celebrity culture will surely be aware that chart-topping musician Taylor Swift and NFL star Travis Kelce have officially tied the knot.

Over the last few weeks, whispers about the pair’s planned big day turned to very loud rumours about them getting hitched in a lavish 1,000-strong ceremony at New York’s iconic arena Madison Square Garden – which turned out to be very much true.

The worst-kept secret in showbiz was confirmed to be the case on Friday when the screens outside the venue flashed up a message reading “JUST&T MARRIED”, with a similar slogan popping up on the licence plate of a car spotted leaving the venue shortly afterwards.

Since then, it’s emerged that the couple went all out for the ceremony, which included the creation of a European-style castle inside the arena, as well as an outside-inside garden theme and wedding looks designed by Jonathan Anderson, the creative director of Dior’s Haute Couture Collections “in close collaboration” with both Taylor and Travis.

Of course, what we all want now is more details, and with the wedding dominating pretty much every entertainment news outlet right now, it may well be hard to keep up with what actually went down at the Swift-Kelce wedding.

Here are some of the biggest celebrity moments you might have missed…

One detail that Taylor’s spokesperson was happy to confirm once the singer was hitched was the fact that Adam Sandler was the one to do the honours, marrying the Grammy winner and her new husband.

Adam and Travis first crossed paths when the latter made a cameo in the Happy Gilmore sequel last year, while the comedy actor has apparently known Taylor for years through his daughters.

He was also a guest on Travis’ New Heights podcast last year, where he told the Kansas City Chiefs star: “When you guys first started dating, my family was like, ‘Yes. Look how good they are together. He’s a gentleman and she’s having so much fun’.”

According to TMZ, Adam was anything but a traditional officiant, delivering a specially-written original song for Taylor and Travis’ big day.

When Madison Square Garden emerged as a potential venue for Taylor’s big day, fans pointed out that the last time she made an appearance there, she sported a Stevie Nicks t-shirt, which may have been an Easter egg for the Fleetwood Mac singer performing at the bash.

According to People magazine, Stevie was, indeed, one of the A-list performers at Taylor and Travis’ wedding reception, where Sir Paul McCartney apparently gave a rendition of the Beatles classic I Want To Hold Your Hand.

TMZ also indicated that Haim might have performed at the event, while Page Six claimed that Tim McGraw, one of Taylor’s earliest musical inspirations, was booked to perform.

Music was always going to be one of the talking points at Taylor Swift’s wedding, and since it was suggested in a TMZ report that the You Belong With Me star had walked down the aisle to a Bridgerton-esque orchestral reimagining of one of her own songs, fans have been speculating about which it could have been.

One we can probably rule out is Blank Space, her 2014 hit about her past bad luck when it came to romance, although a line from this song was embossed on handkerchiefs given to guests on their arrivals.

Days before the wedding, it was reported that the guestlist could reach numbers as high as 1,000, with Taylor even joking that “anyone I’ve ever talked to” would be getting an invite.

Indeed, the list of celebrities in attendance is an especially long one.

Joining the bride and groom’s respective families were some of Taylor’s famous friends, including Selena Gomez, the Haim sisters, Gigi Hadid (who apparently attended with boyfriend Bradley Cooper), Ed Sheeran, Gracie Abrams, Karlie Kloss (and her husband Joshua Kushner), Ice Spice and Lena Dunham.

It seems that Taylor also made good on her promise to invite presenters Greg James and Graham Norton, while Hugh Grant – who previously enjoyed a night of partying with Travis when his now-wife’s Eras Tour landed in London – also put in an appearance.

Reese Witherspoon, Nicole Kidman, Jennifer Lawrence, Tom Cruise were reported to be there, too, as were Lana Del Rey and Sabrina Carpenter, both of whom have appeared on Taylor’s albums Midnights and The Life Of A Showgirl.

Instead, the singer’s representative confirmed that, in lieu of bridesmaids, she had a single “man of honour” in the form of her brother, Austin.

Similarly, Travis didn’t have groomsmen, but his brother Jason Kelce served as best man, while Jason’s daughters were reportedly on flower girl duties.

One of our favourite stories to come out of the wedding so far is that Girls creator Lena Dunham, a long-time friend of Taylor’s, was tasked with performing a speech at the reception.

Per the Daily Mail, true to form, Lena held nothing back with a speech the outlet described as “shockingly rude”, eliciting “gasps” from the crowd, but thankfully plenty of “laughs” too.

Fortunately, it seemed Taylor was a fan, with a supposed “insider” claiming she hailed her friend as a “genius” afterwards.

With a guestlist as big as this one, sometimes the story is who didn’t make the cut.

Among the most notable absentees were Blake Lively and Ryan Reynolds, which at one point would have been unthinkable, but the couple’s relationship with the bride is reported to have turned frosty in recent history.

It should be noted, though, that they were watching their six-year-old daughter competing in a horse show on the day of the wedding, so it could just be that they couldn’t get out of a prior commitment.

While Zoë Kravitz was in attendance, her rumoured fiancé Harry Styles was not.

Harry, of course, once dated Taylor, and is rumoured to be the inspiration for numerous songs on her hit album 1989, including Out Of The Woods and, indeed, Style.

Pop fans will know, however, that Harry was performing his last of 12 record-breaking nights at London’s Wembley Stadium on the night of Taylor’s nuptials, with Variety claiming he was invited to the event, but couldn’t make it due to this previous booking.

The former One Direction star wasn’t the only famous +1 to miss out on the Swift-Kelce wedding, as the Daily Mail claimed that Jack Antonoff’s wife Margaret Qualley was also not in attendance.

Vladimir Putin snubbed Donald Trump’s latest attempts at ending the war in Ukraine by launching a brutal attack on Kyiv just hours after the two leaders spoke.

The US president spoke to the Russian autocrat over the phone for nearly 90 minutes on Saturday while America was celebrating the 250th anniversary of its independence.

The Kremlin claimed their conversation was “business-like and quite constructive”.

But Russia was back to bombing Ukraine by Sunday night.

At least 11 people were killed overnight and a further 46 others injured as Putin’s missile and drone strikes targeted the capital.

It was the second set of strikes on Kyiv in a week.

Trump’s phone call with Putin came after previous US-brokered peace talks between Ukraine and Russia stalled while the White House was focused on its war in Iran.

The US president has also shifted away from his sympathy for Putin in recent weeks and instead acknowledged that Ukrainian leader Volodymyr Zelenskyy is “holding his own” on the battlefield.

Even so, the Kremlin described Putin and Trump’s conversation as “business-like and quite constructive”.

Russian aide Yuri Ushakov said early on Sunday: “The American president once again confirmed his readiness to work towards a rapid end to the fighting and find solutions to overcome the crisis.”

He said Putin was pushing for a “political-diplomatic resolution of the conflict, with due account of Russia’s fundamental approach”.

Ushakov then accused both Ukraine and its European allies of “counting on extending and even escalating the conflict and on terrorism against civilians”, referring to Ukraine’s long-range missile strikes on Russian targets.

Ukrainian president Volodymyr Zelenskyy also revealed he spoke to Trump over the weekend.

He said they had “very good” discussions about the war, including its 1,200-kilometre front line.

He said: “There is a real prospect to end this war and American resolve will have a crucial meaning.”

Zelenskyy and Trump are set to attend this week’s Nato summit in Ankara, where member states are expected to reaffirm support for Ukraine and offer more financial support.

The US is not expected to contribute to any further funding.

Listen to Commons People, the podcast that makes politics easy. Every week, Kevin Schofield and Kate Nicholson unpack the week’s biggest stories to keep you informed. Join us for straightforward analysis of what’s going on at Westminster.