Losing weight in your sleep, without any extra exercise, is a dream for those of us trying to shed a few pounds.
And it may be possible, according to experts who are asking people to doze off in a low-oxygen tent.
Previous research has shown hypoxia — low oxygen levels in the body — can reduce appetite and burn more calories in people with type 2 diabetes.
Run by the University of Portsmouth, the new study will involve sleeping at home in a £2,000 tent that restricts levels of the element.
Experts said it could help people with diabetes who struggle to exercise lose weight, potentially helping patients beat the condition.
Type 2 diabetes affects around 4.4million people in Britain, with 33million thought to have the condition in the US.
Being overweight or having a bad diet is responsible for the vast majority of cases of the condition, unlike type 1 which is usually genetic.
University of Portsmouth researchers are trialling new oxygen tents (pictured) to see if breathing less oxygen could help people with Type 2 diabetes shed pounds while they sleep
Current type 2 treatments include pills which can be taken after meals to regulate glucose levels, and insulin shots if other medicines no longer work.
Scientists are not yet sure why hypoxia helps with weight loss.
But one theory is that cutting oxygen intake, to about the level people get on an airplane or at high altitude, forces the body to work harder to breathe, which burns more calories.
Further evidence is needed on how the tent works. It is not suitable for those with breathing problems or sleep apnoea.
In the new study, people will take part in trials at their own homes, sleeping in a tent set up by researchers for two 10-day periods.
Volunteers will be asked to wear smart monitors, keep a food diary and give blood, urine and stool samples.
What is type 2 diabetes?
Type 2 diabetes is a common condition that causes the level of sugar (glucose) in the blood to become too high.
It can cause symptoms like excessive thirst, needing to pee a lot and tiredness. It can also increase your risk of getting serious problems with your eyes, heart and nerves.
It’s a lifelong condition that can affect your everyday life. You may need to change your diet, take medicines and have regular check-ups.
It’s caused by problems with a chemical in the body (hormone) called insulin. It’s often linked to being overweight or inactive, or having a family history of type 2 diabetes.
They will also have body composition scans and their blood glucose levels tested, to help researchers understand how it effects their bodyweight and diabetes.
During one of the periods, oxygen levels will be set to 15 per cent, similar to levels for passengers on an airplane or for people living at high altitude.
Normal air is made up of around 21 per cent oxygen.
Dr Ant Shepherd, an exercise physiologist, said diabetes is a ‘long-term’ condition in most people that puts them ‘at a greater risk of developing other serious health complications, such as heart disease or eye problems’.
He said: ‘While it is possible to lose weight and reduce blood glucose levels through changes in diet and increased exercise, there are a range of factors and barriers which make these lifestyle changes difficult for some people to initiate.’
The number of people living with type 2 diabetes expected to reach 700million worldwide by 2045.
Dr Shepherd added: ‘It is vital that we find other successful interventions to help us treat and manage the condition, reducing the cost to the NHS and making people’s day-to-day lives better.
‘There’s already quite a lot of evidence from other studies which shows that hypoxia improves the control of blood glucose levels and results in weight loss.
‘We’re not entirely sure why this happens, but we think it’s likely to be because it helps you burn more calories and appetites become suppressed so that people don’t feel as hungry.’
Reducing oxygen levels can cause shortness of breath, headaches, confusion and unexplained exhaustion. In severe cases it can cause a coma or even death.
Reflecting on the tents, trial participant Janet Rennell-Smyth said: ‘It doesn’t feel claustrophobic and, when you get used to the noise of the machine, it feels no different.
‘I’m enjoying participating in the study that may give us, in future, alternate treatments for this disease.
‘I would recommend anyone who is able, to volunteer and help out on this study.’