An unhealthy diet and an indolent life are well known causes of heart disease and stroke. But sleep apnea – where people temporarily stop breathing while asleep because their airway collapses – is also a major risk factor for cardiovascular disease.

While the solutions for an unhealthy diet and lack of exercise are clear, the solutions for sleep apnea are less clear. There are expensive and hard-to-cope-with Cpap (continuous positive airway pressure) machines that help you to breathe while you sleep.

And there are "mandibular advancement devices" that fit in your mouth and push your jaw and tongue forward to keep your airway open while sleeping. Both of these have their downsides.

Mandibular advancement devices, which look a bit like a gumshield, help to hold your airway open and are effective at reducing or getting rid of sleep apnea symptoms, such as daytime sleepiness.

However, they can be uncomfortable in the first few weeks of use, causing drooling, dry mouth and jaw, teeth and gum pain. And they need to be monitored in the long term as they can cause bite changes, which may require orthodontic treatment.

The devices work well for people with mild or moderate sleep apnea, but less well for older people, people with obesity and those with more severe sleep apnea.

Cpap is the gold standard treatment and has been in use for over 40 years. The user straps a mask to their mouth or nose through which air is pumped. However, few people are able to put up with this treatment in the long term. One study found that within three years around half of patients prescribed these machines had stopped using them.

It is hardly surprising that people are on the lookout for cheaper, less invasive, less bulky solutions to this problem.

 Fans of 'mouth taping' claim that they have the solution.

Mouth taping is exactly what it sounds like. You tape your mouth shut, thereby forcing you to breathe through your nose, reducing the likelihood of airway collapse.

Proponents of mouth taping usually recommend using special breathable tape, such as medical tape – rather than, say, Sellotape, masking tape or gaffer tape. And the tape is usually applied vertically, so it doesn't cover the entire mouth.

Not the miracle cure people had hoped for

A recent study showed that mouth taping, as mimicked by closing the mouth in people with sleep apnea, may not be the cure-all that many had hoped for. Although it increased airflow in some participants, it reduced it in others. So mouth taping is certainly not a one-size-fits-all solution.

A few other studies on mouth taping have shown that it can offer some benefit. However, these, like the more recent study, usually contain few participants and tend to only include those with mild sleep apnea.

Another problem with mouth taping is that some people end up exhaling out the side of their mouth where there is no tape – so-called "mouth puffing". This can lead to insufficient oxygen in the blood and potentially too much carbon dioxide, which can cause the body to go into a study stressed state.

There is also evidence that sleep apnea symptoms, such as snoring and reduced airway diameter, get worse in about a third of people who tape their mouths.

Wearing tape around your mouth is also likely to cause irritation. The skin around the mouth is some of the most sensitive in the body – hence being an erogenous zone. The lips contain about 46,000 nerve fibers. (Finger tips, by comparison, have just 3,000 each.)

The skin irritation can also progress to dermatitis. There is also the risk of folliculitis where the hair follicles around the lips become inflamed or infected.

If you're really unlucky, you may also get stripping, where layers of skin come off, leaving fresher underlying layers more exposed, further increasing your likelihood of infection as well as being very sore. (Even a few of those 46,000 nerve fibres being irritated will be agony.)

More importantly, though, mouth taping can be dangerous if you have other respiratory infections or conditions that are already narrowing your trachea, as it can further reduce your oxygen intake and the removal of carbon dioxide.

Taping your mouth shut if you have had a night on the tiles or norovirus ("winter vomiting bug"), say, could even be deadly. If you vomit and have taped your mouth shut, you risk aspiration (vomit in the lungs), which can cause aspiration pneumonia or death.