People who snore heavily are likely to burn far more calories than those who snore lightly, even if they are awake. Researchers from the University of California, San Francisco, discovered that people with serious snoring problems burned around 2,000 calories a day, compared to people who snored lightly.

Those with the worst sleep apnea symptoms burned 373 extra calories a day compared with those with only mild symptoms, US researchers found. While heavy snoring is a nuisance for partners, it can be a sign of a far more serious problem for the snorer. It has also been linked to a greater risk of high blood pressure and cardiovascular problems.

Researchers looked at 212 patients, all of whom snored or had related sleeping conditions like sleep apnea, and findings revealed that the more severe a patient's snoring, the more calories they burned while resting. They concluded that energy expenditure while asleep and resting may be affected by increased reactions in the nervous system caused by snoring and snoring-related conditions. The extra calories consumed are the same as a vigorous 30-minute workout in the gym. Snoring might be linked to energy metabolism, which could explain why some sufferers gain weight easily.

However, snoring is still not a healthy habit — it can be the result of an underlying health problem, such as obesity or sleep apnea.

More than 3.5 million people in the UK are thought to snore. It affects four out of ten men and up to three out of ten women, according to research. Smokers are almost twice as likely as non-smokers to snore because their airways get inflamed and blocked, figures show. Other factors which can make snoring worse include drinking alcohol or taking sleeping tablets, being overweight and sleeping on your back. Colds and allergies can lead to blockages in the throat, causing sufferers to breathe through their mouths.