Reusable water bottles tick many boxes. Not only do they help you stay hydrated and help save money, but they also help cut down on single-use plastic. They've almost become a fashion accessory, with chic stainless steel flasks and viral bottles going viral across TikTok. Sign up for our free Indy100 weekly newsletter Trying to hit the NHS-recommended eight glasses of water a day for adults is an excellent idea, of course, but did you know there’s one way your refillable bottle could potentially be detrimental to your health? According to a study from waterfilterguru.com, reusable water bottles contain an average of 20.8m colony-forming units (CFUs) of bacteria, which equates to 40,000 times more than the microbes on a toilet seat. So what might be the consequences if you continuously sip and refill without washing your bottle properly between uses? We asked health experts to talk through the risks… Bottling up bacteria “A common misconception when it comes to reusable water bottle hygiene is that as you’re typically filling it with pure water and it’s only coming into contact with your own mouth, there’s little need to clean it often,” says Dr Donald Grant, senior clinician at The Independent Pharmacy. However, every time you drink from the bottle, you’re transferring bacteria from your mouth, which can then multiply in the container. “Anything that is reusable can be prone to accumulating dirt, dust or debris and, as a result, bacteria,” says private GP Dr Suhail Hussain. “This is exacerbated by the fact water bottles are the ideal environment for harbouring bacteria due to being moist.” Hard-to-reach crevices – for example, inside a screw top or under a flip-up straw – could also develop mould, and then there’s contamination from other sources. “When you store it in a gym bag, for instance, it can pick up bacteria from the interior of the bag or anything else stored in it, while you can also transfer bacteria from your hands to your bottle,” says Grant. “If your bottle has a valve cap, you may need to lift or twist it with your fingers, and this can transfer bacteria you may have picked up from touching other objects or surfaces.” What types of microbes are found in water bottles? “These might be simple commensals such as streptococcus and staphylococcus, which normally live in symbiosis with their host (i.e. us) but can become problematic if they accumulate or the individual is under the weather,” Hussain says. “Bacteria such as E. coli – a common cause of urine and bowel infections – can often colonise the water bottle following repeated handling, such as taking the cap on and off.” These bacteria can potentially cause a variety of issues. “You may become sick and develop gastric illness, such as diarrhoea or vomiting,” Hussain continues. “Gram negative rods – another common bacterium found in unwashed bottles – can lead to urogenital tract infections and pneumonia.” Grant warns: “If there’s a build-up of mould inside the bottle, this can cause allergy symptoms, such as a runny nose, sneezing, or red and itchy eyes. Symptoms might be more severe for someone with asthma.” How often should you wash your reusable water bottle? “To minimise your risk of getting sick, you should ideally clean your water bottle after each use,” Grant says. “As a minimum, you should aim to wash it thoroughly at least a few times a week.” Hot water and washing up liquid are all you need to banish bacteria on a daily. “Fill the bottle with hot soapy mixture and swill around, or leave to soak in a detergent mixture,” Hussain advises. “Remember to pay special attention to lids/caps and screw top regions – use a clean brush [to scrub them].” If you’ve neglected your bottle for a few days and it needs a deeper clean, Grant suggests: “Soak your bottle overnight in a solution of half vinegar and half water. Rinse the bottle and let it dry fully before using it again.” Storage is also important to help minimise nasty microbes. “Where possible, you should keep your water bottle out of germ-rich environments such as your gym locker or sports bag,” Grant says. “You should also avoid filling your bottle with anything other than water, such as protein shakes, energy drinks, or sugar-rich liquids, as sugar can stimulate the growth of bacteria.” Hussain adds: “Don’t leave a water bottle in the sun for long periods or sitting in the cup holder in the car – the mixture of warmth and moisture is likely to make bacterial overgrowth worse.” Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.

'I apologize to the governments of the United States and of Colombia and to the victims of the crimes that I have committed,' Dario Antonio Usuga said

Special glasses marketed to filter out blue light likely do not make any difference to sleep quality or eye strain from computer use, according to a new review of studies. Blue-light blocking spectacles have been increasingly recommended, often by optometrists, since the early 2000s. Eye patients are frequently prescribed these lenses in many parts of the world with a range of marketing claims existing about their potential benefits. Some of these claims include that the special glasses may reduce eye strain associated with digital device use, improve sleep quality, and also protect the retina from light-induced damage. However, researchers, including those from the University of Melbourne in Australia, say there is “substantial debate” about whether blue-light filtering spectacle lenses have merit in ophthalmic practice. The research, published in the journal Cochrane Database of Systematic Reviews, assessed data from 17 clinical trials on the benefits offered by these glasses for improving visual performance, providing protection to the retina, and improving sleep quality. The review assessed data from individual studies from six countries, each including five to 156 participants, and the period of time over which the lenses were assessed ranging from less than one day to five weeks. Researchers found that there may be “no short-term advantages” with using blue-light filtering spectacle lenses to reduce visual fatigue associated with computer use, compared to non-blue-light filtering lenses. They say it is also currently unclear whether these lenses affect vision quality or sleep-related outcomes. The research review could also draw no conclusions about any potential effects on retinal health in the longer term. “People should be aware of these findings when deciding whether to purchase these spectacles,” study co-author Laura Downie said. “Our findings do not support the prescription of blue-light filtering lenses to the general population. These results are relevant to a broad range of stakeholders, including eye care professionals, patients, researchers and the broader community,” Dr Downie added. However, scientists said the quality and duration of the individual studies part of the review also needs to be considered. “High-quality, large clinical research studies with longer follow-up in more diverse populations are still required to ascertain more clearly the potential effects of blue-light filtering spectacle lenses on visual performance, sleep and eye health,” Sumeer Singh, another author of the study, said. The potential mechanisms by which these lenses might help with eye strain, sleep, and protecting the retina are also unclear, scientists say. “The amount of blue light our eyes receive from artificial sources, such as computer screens, is about a thousandth of what we get from natural daylight,” Dr Singh said. “Filtering out higher levels of blue light would require the lenses to have an obvious amber tint, which would have a substantial effect on colour perception,” he added. But the new research did not find any consistent reports of adverse side effects from using blue-light filtering lenses. Read More A bed bugs epidemic is sweeping the UK – this is why AI can predict Parkinson’s subtype with up to 95% accuracy, study suggests The return of schedules: How parents can make the most of back-to-school energy

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Russian prosecutors asked a court to sentence imprisoned opposition leader Alexei Navalny to 20 years in prison on extremism charges, his ally Ivan Zhdanov said Thursday. According to Zhdanov, the trial against Navalny, which went on behind closed doors in the prison where the politician is serving another lengthy sentence, is scheduled to conclude with a verdict on Aug. 4. In his closing statement released Thursday by his team, Navalny bashed Russian authorities as being governed by “bargaining, power, bribery, deception, treachery ... and not law.” Navalny said: “Anyone in Russia knows that a person who seeks justice in a court of law is completely vulnerable. The case of that person is hopeless." Navalny, 47, is President Vladimir Putin's fiercest foe who exposed official corruption and organized major anti-Kremlin protests. He was arrested in January 2021 upon returning to Moscow after recuperating in Germany from nerve agent poisoning that he blamed on the Kremlin. The authorities sentenced him to 2 1/2 years in prison for parole violations and then to another nine years on charges of fraud and contempt of court. The politician is currently serving his sentence in a maximum-security prison east of Moscow. He has spent months in a tiny one-person cell, also called a “punishment cell,” for purported disciplinary violations such as an alleged failure to properly button his prison clothes, properly introduce himself to a guard or to wash his face at a specified time. Navalny's allies have accused prison authorities of failing to provide him with proper medical assistance and voiced concern about his health. The new charges relate to the activities of Navalny’s anti-corruption foundation and statements by his top associates. His allies said the charges retroactively criminalize all the foundation's activities since its creation in 2011. Navalny has rejected all the charges against him as politically motivated and has accused the Kremlin of seeking to keep him behind bars for life. One of his associates — Daniel Kholodny — was relocated from a different prison to face trial alongside him. The prosecution has asked to sentence Kholodny to 10 years in prison. The trial against the two began a month ago and went along swiftly by Russian standards, where people often spend months, if not years, awaiting for their verdict. It was unusually shielded from public attention and Navalny's lawyers haven't offered any comments on the proceedings. Navalny, in his sardonic social media posts, occasionally offered a glimpse of what was going on with his case. In one such post, the politician revealed that a song by a popular Russian rapper praising him was listed as evidence in the case files, and claimed that he made the judge and bailiffs laugh out loud as the song was played during a court hearing. In another, he said that the case files linked him to U.S. mogul Warren Buffet. In his closing statement, Navalny referred to the recent short-lived armed rebellion by the fighters of Russia's private military company Wagner, after which their chief and the leader of the mutiny, Yevgeny Prigozhin, walked free, even though a number of Russian soldiers were killed by his troops. “Those who were declared traitors to their Motherland and betrayers, in the morning killed several Russian army officers as the entire Russia watched in astonishment, and by lunch agreed on something with someone and went home,” Navalny said. “Thus, law and justice in Russia were once again put in their place. And that place is not prestigious. One sure can't find them in court," the politician said. Read More Ukraine war’s heaviest fight rages in east - follow live Charity boss speaks out over ‘traumatic’ encounter with royal aide Jailed Alexei Navalny ‘forced to listen to Putin speech for 100 days in a row’ Who is Yevgeny Prigozhin? Russia restricts movement of British diplomats over Ukraine support - live news

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