Wearing an activity device that counts how many steps you have taken does not appear to improve the chances of losing weight, research suggests.
The two-year long study in the Journal of the American Medical Association (JAMA) included nearly 500 overweight volunteers who were asked to diet and take more exercise.
Half were given a fitness tracker to help them keep tabs.
This group had lost less weight than the other one by the end of the trial.
The study authors say this does not mean people should ditch the technology altogether, but neither should they put too much faith in them, at least as a slimming aid.
Manufacturers say that the technology has moved on since the study, and that their own research suggests activity trackers can help with weight loss alongside diet and exercise regimes.
Gimmick?
Despite the popularity of activity trackers, there have been very few studies to see what actual impact they have on weight and fitness levels.
The University of Pittsburgh research is one of the first randomised trials to gather such evidence.
The investigators found that over the course of the study, the volunteers who wore the fitness trackers had lost, on average, about 8lb (3.6kg).
In comparison, the control group that were not given these devices lost about 13lb (5.9kg).
The study authors say there are many possible explanations for this surprising finding but, as yet, no proof.
Lead researcher Dr John Jakicic said: "People have a tendency to use gadgets like these for a while and then lose interest with time as the novelty wears off.
"And we did see a drop off in the usage data as the study went on."
Perhaps people who use fitness trackers became fixated on exercise goals and forgot to follow the diet advice, Dr Jakicic suggested.
"You might think to yourself, 'I'm being so active I can eat a cupcake now,'" he said.
Dr Jakicic said he would like to explore if certain people were more likely than others to benefit from using the technology.
For example, a person who was very goal-driven might find tracking their exercise regime very motivating. - but others might just find it depressing.
"It might be very discouraging if you can see that you are not hitting your target all the time," he said.
He acknowledged that technology had moved on since the study began, but he did not think that would alter the findings.
"What these devices tell us and how we use the information has not changed," he said.
According to research company CCS Insight, UK sales of wearable devices - activity trackers and smart watches - are expected to reach five million, with 10 million devices expected to be in use before the end of 2016.
Dr David Ellis, a psychologist at Lancaster University, who has been researching the rise of consumer health wearables said the JAMA study was helpful because it focused on people who might not normally go out and buy an activity tracker.
"Fitness trackers are more likely to be bought by people who already lead a healthy lifestyle and want to monitor their progress. So it's hard to say if they are useful for everybody," he said.
"In real life, obviously, most people won't get the level of support to lose weight that the people in this study did.
"They would have to do it on their own, so wearing a device might be better than nothing. We just don't know."
WASHINGTON (CNN) —Hillary Clinton used humor Friday to address her recent pneumonia diagnosis, telling an audience of black women in Washington that the upside was that it "finally got some Republicans interested in women's health."
"I am also thrilled to be back on the campaign trial. As the world knows, I was a little under the weather recently," Clinton said. "The good news is my pneumonia finally got some Republicans interested in women's health."
Democrats have long hit Republicans for, in their view, ignoring women's health needs by pushing to defund Planned Parenthood and other policy positions.
Clinton was diagnosed with pneumonia last week, but opted to ignore her doctor and continued to campaign over the weekend. On Sunday, at a 9/11 memorial ceremony, the former New York senator seemingly collapsed after leaving the event early. She had to cancel three days of campaigning because of the diagnosis.
"Looking back I know I should have followed my doctors orders to rest, but my instinct was to push through it," Clinton said at the Black Women's Agenda forum. "That is what women do every day."
Last month, as Trump and his supporters pushed conspiracy theories about Clinton's health, the Democratic nominee went on Jimmy Kimmel's late night show and opened a jar of pickles to show her strength.
"Back in October, the National Enquirer said I would be dead in six months. So with every breath I take I feel like I have a new lease on life," Clinton joked.
'No erasing' Trump birther history
Clinton weighed in on Republican nominee Donald Trump trying to walk back questions he raised about President Barack Obama's country of birth and American citizenship.
Trump's campaign issued a statement on Thursday night that said the Republican nominee, who rose to political prominence by questioning the president's birthplace, now believes Obama was born in the United States. Trump has not publicly expressed that sentiment himself.
Clinton said Friday that "there is no erasing" Donald Trump's birther history, arguing that Trump's campaign was "founded on this outrageous lie."
"For five years he has led the birther movement to delegitimize our first black president," Clinton said. "Barack Obama was born in America plain and simple and Donald Trump owes him and the American people an apology."
Clinton added, "My friends, there is no new Donald Trump. There never will be."
Friday's event was a friendly one for Clinton. African-American women have been a supportive voting bloc for Clinton for decades and the former secretary of state said that she "would not be the Democratic nominee for president of the United States were it not for black women."
Clinton, nodding to a popular hashtag on social media and phrase used to celebrate black women's resilience, added, "You are proof that yes indeed, black girl magic is real."
Napping for more than an hour during the day could be a warning sign for type-2 diabetes, Japanese researchers suggest.
They found the link after analysing observational studies involving more than 300,000 people.
UK experts said people with long-term illnesses and undiagnosed diabetes often felt tired during the day.
But they said there was no evidence that napping caused or increased the risk of diabetes.
The large study, carried out by scientists at the University of Tokyo, is being presented at a meeting of the European Association for the Study of Diabetes in Munich.
Their research found there was a link between long daytime naps of more than 60 minutes and a 45% increased risk of type-2 diabetes, compared with no daytime napping - but there was no link with naps of less than 40 minutes.
Sleeping patterns
The researchers said long naps could be a result of disturbed sleep at night, potentially caused by sleep apnoea.
And this sleeping disorder could increase the risk of heart attacks, stroke, cardiovascular problems and other metabolic disorders, including type-2 diabetes.
Sleep deprivation, caused by work or social life patterns, could also lead to increased appetite, which could increase the risk of type-2 diabetes.
But it was also possible that people who were less healthy or in the early stages of diabetes were more likely to nap for longer during the day.
Shorter naps, in contrast, were more likely to increase alertness and motor skills, the authors said.
'Early warning sign'
Naveed Sattar, professor of metabolic medicine at the University of Glasgow, said there was now a lot of evidence of some kind of link between sleep disturbances and diabetes.
"It's likely that risk factors which lead to diabetes also cause napping. This could include slightly high sugar levels, meaning napping may be an early warning sign of diabetes," he said.
But proper trials were needed to determine whether sleeping patterns made a difference to "real health outcomes".
Dr Benjamin Cairns, from the cancer epidemiology unit at the University of Oxford, said the findings should be treated with caution.
"In general, it is not possible to make conclusions about cause and effect based on observational studies alone, because usually they cannot rule out alternative explanations for their findings," he said.
Afterwards, Ms Cafferkey's lawyer, Joyce Cullen, said her client was "relieved" to have been cleared of wrongdoing after "willingly" putting her life at risk to help people suffering from Ebola.
She said that the medics returning from Sierra Leone had encountered "chaotic scenes" and put the focus on Public Health England for the ordeal her client had endured.
"Public Health England were unprepared for the volume of people returning from countries affected by Ebola," Ms Cullen said.
"There were also serious failures in communication amongst the Public Health England staff.
"It is perhaps ironic that given the criticisms made about Public Health England processes, it was their complaint which led to the Nursing and Midwifery Council investigation and these proceedings being initiated against Pauline."
'Lucky to survive'
Ms Cullen concluded by saying that Ms Cafferkey would "never have knowingly put anyone in danger".
"Pauline was lucky to survive and since her return from Sierra Leone has continued to suffer from ill health," she said.
"The NMC disciplinary process has been very upsetting and stressful for Pauline. However, she's delighted that the panel has made the decision that she has no case to answer and that she's now able to continue her nursing career in Scotland, where she will carry on looking after families in Blantyre, who've been very appreciative of her skills and dedication."
How the case against Pauline Cafferkey collapsed - BBC Scotland reporter Philip Sim
Pauline Cafferkey has come out of her misconduct hearing with a clean bill of health - but the same can't be said for any of the other parties involved.
The Nursing and Midwifery Council had lodged a series of charges against her, including that she had been "dishonest", but was forced to reconsider after medical evidence came to light.
This saw the group's lawyer actually arguing against her own charges, in a bid to have mention of dishonesty scrapped.
In fact she made such a convincing case that the remaining, watered-down charges were never likely to win over the panel.
And if the NMC looked bad, it was even worse for Public Health England - ironically, given they raised the original complaint against Ms Cafferkey.
The hearing was told of "chaotic" scenes at PHE's Heathrow screening centre, with patients being told to administer their own tests. There were constant miscommunications between doctors, including one who left messages at the wrong hospital. In the end, many present at the hearing were puzzled as to why it was Ms Cafferkey who was under the microscope and not one of several others who appear to have let her down.
It now seems as if the case against Pauline Cafferkey had fallen apart before the hearing even began - raising questions as to why she had to go through it in the first place.
After Ms Cafferkey was cleared, First Minister Nicola Sturgeon tweeted: "Sending my very best wishes to Pauline Cafferkey. Her bravery is an inspiration to all of us."
Last month it emerged that Ms Cafferkey would face charges from the Nursing and Midwifery Council (NMC) over alleged misconduct when she returned to the UK in December 2014.
When the panel hearing got under way on Tuesday, the NMC withdrew a charge of dishonesty, leaving her facing three charges.
The first charge alleged that while in a Public Health England screening area, inside Terminal 4 at Heathrow, she allowed an incorrect temperature to be recorded on her screening form.
The second charge alleges that she left the screening area without reporting her true temperature to medics.
The third charge alleged that she did not tell a doctor she had recently taken paracetamol.
After deliberating overnight, the panel ruled on Wednesday that Ms Cafferkey had not been guilty of misconduct in relation to all charges.
'Exhausted state'
Panel chairman Timothy Cole told Ms Cafferkey that in her "exhausted and increasingly unwell state" she did not set out to mislead staff.
He said Ms Cafferkey's conduct in leaving the screening area without flagging up her elevated temperature could only be explained by illness and exhaustion.
Commenting on the outcome, NMC chief executive and registrar, Jackie Smith, said: "As the independent panel recognised, the NMC has an overarching duty to protect the health and wellbeing of the public and need to ensure the maintenance of public confidence in the profession.
"The referral from Public Health England showed a highly unusual set of circumstances that clearly required a thorough and proper investigation. In circumstances like this, it is right for an independent panel to hear all the evidence to decide if any action is required."
The decision to clear Ms Cafferkey was based on an agreed narrative of facts which had been presented to the panel on Tuesday.
These characterised the screening area at Heathrow airport as "busy, disorganised and even chaotic" when Ms Cafferkey and other medics arrived back from Sierra Leone.
They showed that the nurse's temperature was recorded twice by a doctor, in the presence of another person referred to as "registrant A", at more than 38C.
The doctor claimed that "registrant A" stated that she would record the temperature as 37.2C on Ms Cafferkey's screening form and then they would 'get out of there and sort it out'".
Ms Cafferkey recalled the words "let's get out of here" being used but could not remember who said it or who entered the incorrect temperature on her screening form.
The panel also heard that Ms Cafferkey accepted that her temperature had been measured at above 38C, yet allowed a reading of 37.2C to be recorded, after which she continued to the arrivals area.
It was heard that a temperature above 37.5C "is an elevated or pyrexial (feverish) temperature that requires further assessment and should be reported to a consultant".
Ms Cafferkey admitted taking paracetamol at some point but did not mention it to a doctor when she returned to the screening areas.
Severe viral load
That doctor found her temperature to be normal and cleared the nurse to fly back to Scotland.
Hours later she was diagnosed with one of the most severe viral loads of Ebola ever recorded.
Doctors' evidence to the panel stated that early symptoms of Ebola would have impaired Ms Cafferkey's judgement and that there was no evidence she had been deliberately dishonest to staff.
The nurse, from Halfway, Cambuslang, contracted Ebola while working as part of a British team at the Kerry Town Ebola treatment centre in 2014.
She spent almost a month in isolation at the Royal Free hospital in London at the beginning of 2015 after the virus was detected when she arrived back in the UK.
Ms Cafferkey was later discharged after apparently making a full recovery, and in March 2015 returned to work as a public health nurse at Blantyre Health Centre in South Lanarkshire.
However, in the months that followed, her health suffered as she had issues with her thyroid, her hair fell out and she had headaches and pains in her joints.
Scientists say early experiments suggest it may one day be possible to make babies without using eggs.
They have succeeded in creating healthy baby mice by tricking sperm into believing they were fertilising normal eggs.
The findings in Nature Communications, could, in the distant future, mean women can be removed from the baby-making process, say the researchers.
For now, the work helps to explain some of the details of fertilisation.
End of mum and dad?
The University of Bath scientists started with an unfertilised egg in their experiments.
They used chemicals to trick it into becoming a pseudo-embryo.
These "fake" embryos share much in common with ordinary cells, such as skin cells, in the way they divide and control their DNA.
The researchers reasoned that if injecting sperm into mouse pseudo-embryos could produce healthy babies, then it might one day be possible to achieve a similar result in humans using cells that are not from eggs.
In the mouse experiments, the odds of achieving a successful pregnancy was one in four.
Dr Tony Perry, one of the researchers, told the BBC News website: "This is the first time that anyone has been able to show that anything other than an egg can combine with a sperm in this way to give rise to offspring.
"It overturns nearly 200 years of thinking."
Those baby mice were healthy, had a normal life expectancy and had healthy pups of their own.
Fertilisation
The goal of the researchers is to understand the exact mechanisms of fertilisation because what happens when a sperm fuses with an egg is still a bit of a mystery.
For example, the egg completely strips the sperm's DNA of all its chemical clothing and re-dresses it.
That stops the sperm behaving like a sperm and makes it act like an embryo, but how the "costume change" takes place is not clear.
Removing the need for an egg could have a wider impact on society.
Dr Perry said: "One possibility, in the distant future, is that it might be possible that ordinary cells in the body can be combined with a sperm so that an embryo is formed."
In other words, two men could have a child, with one donating an ordinary cell and the other, sperm.
Or one man could have his own child using his own cells and sperm - with that child being more like a non-identical twin than a clone.
Dr Perry stressed that such scenarios were still "speculative and fanciful" at this stage.
Earlier this year in China, scientists were able to make sperm from stem cells and then fertilise an egg to produce healthy mice.
Dr Perry suggested that combining the two fields of research may eventually do without the need for sperm and eggs altogether.
Prof Robin Lovell-Badge, from the Francis Crick Institute, commented: "I'm not surprised that the authors are excited about this.
"I think it is a very interesting paper, and a technical tour de force and I am sure it will tell us something important about reprogramming at these early steps of development that are relevant to both fertilisation and single cell nuclear transfer [cloning].
"And, perhaps more broadly, about reprogramming of cell fate in other situations.
"It doesn't yet tell us how, but the paper gives a number of clear pointers."
A seven-day NHS is "impossible" to achieve with the current funding and staffing levels, the chief executive of NHS Providers says.
Chris Hopson told the BBC's Andrew Marr programme that "something has to give" and there should be a debate about which services to sacrifice "rather than pretend the gap doesn't exist".
Figures show waiting times and delayed hospital discharges at record levels.
The government says it is giving NHS England the £10bn it asked for.
Health Secretary Jeremy Hunt has called for a "seven-day NHS" since 2015 afterhis department concluded that there was a "clear link between poorer outcomes for patients and uneven service provision at the weekend".
'Relative risk'
Introducing a seven-day NHS also formed part of the Conservative Party's manifesto, and its based on data which suggests that patients are 16% more likely to die if they are admitted on a Sunday compared with a Wednesday.
However, the reasons for this have been contested, and medical professionals agree that people who arrive in hospitals at weekends tend to be sicker than those who do so during the week.
NHS Providers, the organisation that represents hospitals in England, says unless urgent funding is provided it will have to cut staff, bring in charges or introduce "draconian rationing" of treatment, for example, of non-urgent operations.
It highlights that 80% of England's acute hospitals are in financial deficit, compared with 5% three years ago - while missed A&E waiting time targets have risen from 10% to 90%.
Mr Hopson said the NHS was under the "greatest pressure that we've been for a generation".
He added: "Jeremy Hunt and others have made a very strong case for seven-day services, but it seems to us it's impossible on the current level of staff and the current money we have available."
Analysis
By Nick Triggle, BBC health correspondent
On almost every measure, the last few years has seen a decline in performance in the NHS in England (although the rest of the UK is not immune to this either).
That should not come as a surprise. Overall the last five years has seen the tightest financial settlement in the history of the NHS.
To stem the decline, ministers agreed 2016-17 would see the biggest cash injection - nearly 4% above inflation - since the Labour years.
The jury is still out over whether that will have an impact. But even if it does the following years will see much smaller rises so the fear is any respite will only be short-term.
Yes there is a productivity drive, but it is the most ambitious one ever set. Most observers believe it would be amazing if it was achieved in full.
And that's before the seven-day initiative is even factored in.
So that leaves the government with three choices: Put more money in, accept a further decline in standards or cut back on what the NHS does. None of them are particularly palatable for the government.
Mr Hopson also said the numbers of hospitals in deficit, and the missed waiting times for A&E, showed there was "clearly a system-level problem - it's not a problem of poor management".
People on the front line in the NHS were saying that they "cannot provide the right quality of care, and meet the performance standards, on the money that's available".
Mr Hopson said he wanted to see the seven-day NHS idea abandoned, and more money put into the NHS through general taxation.
But he added that the NHS's chairs and chief executives were "absolutely signed up" to deliver "stretching savings targets, and stretching productivity".
His warning comes days before the Commons Health Select Committee will decide whether to launch a special inquiry into the state of the NHS in England and two months before the government announces its spending plans in the Autumn Statement.
Fines for missing targets in A&E, cancer and routine operations have also been scrapped altogether and a new failure regime is being set up for the worst-performing trusts.
Home Secretary Amber Rudd rejected Mr Hopson's suggestion that a seven-day NHS was impossible to deliver.
"The health secretary and the government consulted with [NHS Chief Executive] Simon Stevens and asked him about what scale of money was necessary - we've delivered on that money," she told Andrew Marr.
UK funding
But Chris Ham, chief executive of the King's Fund think tank, said the government should heed "warning signs" and not wait for a "full scale crisis to develop".
He added: "It is simply not realistic to expect hard-pressed staff to deliver new commitments like seven-day services while also meeting waiting time targets and reducing financial deficits."
Diane Abbott MP, shadow health secretary, said: "Years of Tory underfunding of the NHS has made it is impossible to provide the right quality of service and meet performance targets.
"The government needs to properly fund the NHS if it is to function properly. This is what Labour would do."
In June, Northern Ireland Finance Minister Máirtín Ó Muilleoir said its health service was to receive an extra £72m to help deal with pressures in the service, bringing the total additional funding for health to £200m in 2016-17.
Scotland's First Minister Nicola Sturgeon announced in June that minimum staffing levels in Scotland's NHS are to be enshrined in law.
And Welsh Assembly Finance Minister Jane Hutt announced last December that the NHS would be getting a net boost of £278m under the Welsh government's spending plans for 2016-17.
