We have a problem: many of us are struggling to breathe. A lot of people have a chronic blocked nose. Four in 10 people snore. Over 300 million worldwide have asthma and millions suffer from sleep apnoea, or night choking.

This is a new phenomenon for humans. Just a few hundred years ago, we had wider mouths, larger nasal cavities and straight teeth, which likely meant that we could breathe freely through our noses, says James Nestor, author of Breath: the New Science of a Lost Art.

We got here by turning to a diet of mushy, soft-processed food, which did not give our jaws and faces the workout needed to grow properly, resulting in smaller nasal passages and difficulty breathing. But you can make changes for the better, says Nestor, and cut down on your snoring, sinus infections and even keep your blood pressure in check.

Breathe through your nose

We are designed to breathe through our noses almost all of the time, and use our mouths only as a back-up, says Nestor. The nose has tiny hairs inside it which filter pollutants out of the air, and humidifies and warms it so it is more palatable for the lungs.

Air also reacts differently when it’s inside your body, depending on whether it came in through your nose or mouth. When you breathe through your nose, air is pushed through a maze of bony structures where it is mixed with nitric oxide, a gas that dilates blood vessels and helps you absorb up to 20 per cent more oxygen.

Although you may feel like panting when exercising, this might not be a good way to get more oxygen into your body, says Nestor: “When you breathe that way, you are inhibiting oxygen.” But breathing through the nose when exercising is not something that can be achieved overnight. Nestor recommends training yourself over the course of weeks or months, sticking to a level of exertion that you can maintain with long, deep breaths through the nose.

Try: Humming. Its vibrations can increase the amount of nitric oxide that your body creates up to twenty-fold, according to 2006 research.

Shut your mouth

In researching the book, Nestor tried breathing solely through his mouth for two weeks. The results were disastrous: after five days, his blood pressure had risen 13 points without the relaxing effects of nitric oxide.

Mouth breathing was particularly bad for his sleep: after 10 days, the amount of time he spent snoring a night rose by 4,280 per cent, and he started suffering from sleep apnoea.

This night-time choking can have further deleterious effects, due to its negative effect on sleep cycles. The hormone vasopressin, which regulates water storage, is released as you sleep soundly. When Nestor’s sleep was disrupted by mouthbreathing-related apnoea, he woke up more frequently to use the lavatory.

Consult a sleep specialist who can help you with mouthbreathing-related apnoea.

Go slow

Too much and too fast: Nestor argues that we are breathing too much and too quickly, reducing one critical compound in our body: carbon dioxide. Ironical, you say? But that is because we misunderstand what CO2 does, he says. The gas actually has a critical function in the body, helping to split oxygen molecules off red blood cells, so it can be used by the body. Breathing too fast, like when hyperventilating during a panic attack, can make you light-headed and your fingers and toes tingle, as your carbon dioxide levels drop rapidly, making it more difficult for your body to absorb oxygen. This in turn can make you feel breathless, which causes you to breathe more, making the problem worse.

Not only can slow breathing be hugely beneficial for those with anxiety, it has also been shown to help asthma, which can often be triggered by fast breathing, such as after exercise. A 2014 study asked 120 asthma sufferers to frequently measure their carbon dioxide levels, and breathe more slowly when they fell below 5.5 per cent, to bring them up again.

A month later, 80 per cent of participants experienced markedly fewer attacks.

Try: If you want to be precise about it, the perfect formula seems to be inhaling and exhaling for 5.5 seconds each, which should give you 5.5 breaths per minute. There are myriad timers online or in apps which can count this for you. If you prefer to do it tech-free, then try getting down on your knees. Prayers from several religions work out at this exact tempo. “Prayer heals, especially when it’s practised at 5.5 breaths a minute,” says Nestor.

Chew gum

Given our mushy diets of pasta, cooked vegetables and cake, our mouths are no longer getting the workouts they were designed for. As a result, about 400 years ago, our mouths “started growing much smaller, which is why, for the first time in human evolution, we became a species with chronically crooked teeth”, says Nestor.

This left our faces to change shape, growing up instead of out, which squashed the space available in the head for the sinuses and airways. As a result, we find breathing harder than before.

But there is hope, says Nestor, as the facial bones are among some of the most plastic in the body.

To stimulate growth of the jaw bone, all you need to do is vigorously engage the chewing muscles.

Try: If you are unwilling to shift your diet away from delicious soft white bread, you can replicate this by chewing gum, says Nestor.

Correct your “oral posture”

As our mouths have become smaller, our bodies have readjusted themselves to compensate. Our backs have gone from a natural J-shape to an S, with the shoulders drooping forwards and necks stuck out to open up airways that are mildly blocked by tongues that are too large for our small mouths, says an expert quoted by Nestor in the book.

This can cause us serious back pain and headaches, says Nestor, so we should try to correct it as much as we can by practising good oral posture.

Try: Keep your lips together, your tongue on the roof of the mouth and your teeth lightly touching. Balance your head so it is perpendicular to your spine, and keep your back straight.

The Daily Telegraph

Read more