People with type 2 diabetes could be helped to lose weight while they sleep in a new treatment being tested by scientists.
University of Portsmouth researchers need volunteers to see if breathing lower amounts of oxygen (hypoxia) improves blood glucose levels.
Previous evidence has shown hypoxia can reduce appetite and burn more calories in people with type 2 diabetes.
Volunteers will sleep at home in a tent set up by the study team.
Over the next 20 years, the number of people living with type 2 diabetes is expected to reach 700m worldwide and researchers say creating a range of potential treatments for the condition is vital.
The study will investigate if sleeping in a special tent that creates a lower oxygen environment, is effective at improving blood glucose control and has an impact of weight loss.
Dr Ant Shepherd, senior lecturer in the university's school of sport, health and exercise science, said: "Type 2 diabetes is a common condition that causes blood glucose levels to become too high.
"For many people, it is a long-term condition which can negatively impact their everyday life and put them at a greater risk of developing other serious health complications, such as heart disease or eye problems.
"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."
Throughout the trial, volunteers will be asked to wear smart monitors, keep a food diary and provide blood, urine and stool samples.
They will also have body composition scans and their blood glucose levels tested, to help researchers understand the body's response to hypoxia.
Dr Shepherd added: "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."
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"