The funniest thing about World Sleep Day, one in three people have at least mild insomnia, and will probably keep nodding off during the celebration … of sleep.

The marketing doesn’t help.

According to the World Sleep Society, the special day (March 13 this year) is “designed to raise awareness of sleep as a human privilege that is often compromised by the habits of modern life”.

Read that 10 times in a row and you’ll sleep like a log.

Also compromising World Sleep Day’s mission to raise awareness about sleep as a health issue is this declaration on the society’s website: “Written permission is required to use the words World Sleep Day”.

Let’s go crazy and talk about sleep research anyway

That sound of violent gargling and gasping in the night is probably a portly family member choking on their tonsils – symptoms of Obstructive Sleep Apnoea (OSA).

More likely a man, and known to frequently complain of feeling drowsy through the day.

According to berkeleywellness.com, this is a normal-sized tongue. You probably won’t gargle or choke on it in your sleep. Photo: Berkeley Wellness

You don’t need to be obese to suffer sleep apnoea – it can be caused by a large neck circumference (more than 43cm for men and 40cm for women), old age, smoking, sedatives and certain facial abnormalities, including a high, narrow, elongated, soft palate, a small chin, an abnormal bite and a small jaw.

Still, obesity is a major cause – and losing weight reduces the severity of symptoms.

But no one understood what exactly was causing the improvement.

A new study from the Perelman School of Medicine at the University of Pennsylvania has apparently solved the puzzle.

Using magnetic resonance imaging to measure the effect of weight loss on the upper airway in obese patients, the researchers found that a fat tongue was causing some of that gargling and choking.

Hence, reducing weight off the tongue (more talking at a sprint, less eating) lessens the severity of symptoms.

And this is the tongue carrying too much fat and will keep you up at night. Lose weight, sleep better. Photo: Berkeley Wellness

“Most clinicians, and even experts in the sleep apnoea world, have not typically focused on fat in the tongue for treating sleep apnea,” said Dr Richard Schwab, co-medical director at Penn Sleep Centre, and co-author of the study.

“Now that we know tongue fat is a risk factor and that sleep apnoea improves when tongue fat is reduced, we have established a unique therapeutic target that we’ve never had before.”

Dr Schwab’s team is now investigating whether some patients who are not obese but who have “fatty” tongues could be predisposed to sleep apnoea, but are less likely to be diagnosed.

And another thing to chew over

Not so long ago, dietary fibre wasn’t sexy.

You ate it to plump up the old stool and make an easy passing of yesterday’s lunch.

Then everyone went mad about gut health and the microbiome, a whole world that lives in there.

It was important. Because poor gut health maybe gave you Parkinson’s or a thyroid issue, or rheumatoid arthritis and type 1 diabetes.

Not to mention the problems one never used to talk about: Irritable bowel syndrome, constipation, diarrhoea, heartburn and bloating.

For a while, probiotics – fermented foods such as yoghurt and sauerkraut – took all the credit for keeping the microbiome’s lights on.

Problem: The little helpful bugs in yoghurt and kombucha weren’t thought to survive the journey through the stomach, sadly fizzing to nothing.

Enter, prebiotics: Indigestible foods hardy enough to survive intact, reporting to the lower bowel for bug-feeding duties.

These were leeks, artichokes, and onions, some whole grains. Apple peel is a good one. They sacrifice themselves as dinner for gut bacteria: The world is in balance, and life doesn’t smell too bad.

The fibre in leeks and artichokes will survive the small intestine, set up camp in your lower bowel, ferment and create good life-giving bacteria, and somehow send you off to sleep. Photo: supplied

Not that there’s necessarily been a mad rush in the general population to consume more fibre (people are doing it tough enough trying to give up burgers).

Even so, prebiotics became the new dietary thing to at least talk about, and was no longer an under-sung hero.

But get this.

A new study – ‘Dietary prebiotics alter novel microbial dependent faecal metabolites that improve sleep’ – suggests a healthy lower bowel, fed on plenty prebiotics, may serve to alleviate the stress of life, and allow a less broken sleep to become one’s habit.

At least that’s the promise the experiment made to rats.

How they came to this conclusion

The University of Colorado researchers fed adolescent male rats on either standard chow or chow infused with prebiotics.

They tracked the physiological changes before and after the rats were put under stress.

In line with a previous study, the rats on the prebiotic diet spent more time in restorative non-rapid-eye-movement (NREM) sleep.

After stress, they also spent more time in rapid-eye-movement (REM) sleep, “which is believed to be critical for recovery from stress”.

The sleepless rats, after being stressed, suffered an unhealthy flattening of the body’s natural temperature fluctuations and a drop in healthy diversity of their gut microbiome.

Those fed prebiotics were somewhat protected from these effects.

The sleepless rats also experienced dramatic spikes in allopregnanolone precursor and ketone steroid, potentially sleep-disrupting metabolites.

Those on the prebiotic diet saw no such spike.

“The biggest takeaway here is that this type of fibre is not just there to bulk up the stool and pass through the digestive system,” said Dr Robert Thompson, a postdoctoral researcher in the Department of Integrative Physiology and lead author of the study.

“It is feeding the bugs that live in our gut and creating a symbiotic relationship with us that has powerful effects on our brain and behaviour.”