We’ve all heard of hyperventilation, a condition linked with panic attacks, involving very fast breathing and a dramatic loss of carbon dioxide, the gas that we normally breathe out. This leads to hypocapnia (loss of carbon dioxide), and the standard treatment is to breathe into a paper bag, which gets some of the missing carbon dioxide back into the lungs.

Traditionally we understand hyperventilation as a short-term condition. But doctors and scientists are raising questions about whether abnormal breathing can have a more long-term effect on our bodies. Is how we breathe important in more ways than simply determining oxygen intake and helping our bodies to relax? Does the way we breathe cause long-term chemical and physiological effects? It’s a contentious subject. In fact, you might think that lack of carbon dioxide in your body shouldn’t be a problem; after all, breathing is about filling your lungs with oxygen and expelling carbon dioxide. How can you have too little of a waste product? However, it’s well known that if you lose too much carbon dioxide from your blood by breathing too deeply or too often — ie, what most of us associate with panic attacks — you upset the acid/alkaline balance in the body and trigger harmful changes in the metabolism.

What’s controversial is whether this can cause long-term problems. Eight years ago, Dutch researchers ran some hotly debated trials, reported in the New Scientist, pooh-poohing the whole idea of hyperventilation and asserting that hyperventilation syndrome symptoms did not seem to be dependent on levels of carbon dioxide in the blood. At the same time, the Journal of Psychosomatic Medicine also ran an editorial questioning whether hyperventilation syndrome existed. Since then, however, there has been research indicating that breathing out too much carbon dioxide may be responsible for longer-term disorders.

A review article in the New England Journal of Medicine in 2002 concluded that low carbon dioxide in the blood — hypocapnia — “appears to induce substantial adverse physiological and medical effects” in people with pneumonia and heart failure. A review from the University of Westminster last year described how the effects of hypocapnia on blood flow and oxygen in the body could cause increased joint and muscle pain. And recent authoritative trials from Australia and New Zealand have shown that a breathing technique called Buteyko — which trains people to breathe in a controlled way so that they do not become depleted of carbon dioxide — brought significant reductions in the amount of medication people with asthma had to use.

David Beales, a GP in Gloucester, believes that all this points to the importance of being able to measure over-breathing and then to prescribe treatments to bring it back into balance, such as cognitive behaviour therapy, hypnosis and breathing training. Dr Beales is likely to stoke the fires of scientific debate further by promoting the use of a new lightweight device called the CapnoTrainer, which provides a moment-bymoment readout of your carbon-dioxide levels on a laptop. He claims that it can help people with various levels of stress-related conditions.

He does have an interest in its success; he is medical adviser to the American company Better Physiology Ltd, which developed the product. This autumn he gave a series of lectures and workshops to doctors at the Royal Society of Medicine on the carbondioxide issue. And he says that what gets their attention is the potential of the CapnoTrainer to enable them to do something for “heart-sink” patients, those with previously unmeasurable and vague symptoms. It gives them something to measure.

Beales believes that common symptoms that many people come to GPs with, such as lack of energy, headaches and depression, can often be the result of overbreathing and the impaired blood flow to the brain that results.

“It’s standard medical textbook stuff, which most doctors forget as soon as they leave med school,” Dr Beales says, arguing that lowered carbon dioxide in the blood results in a lowering of blood pressure, which leads to less oxygen getting to brain and muscles. Once the problem has been identified, he says, people can bring their breathing back into balance.

Among those who claim to have benefited are about 100 officers in several police forces. In South Yorkshire, for example, about 400 police officers every year need counselling because of post-traumatic stress disorder or other stress-related problems. Kevin Tobin, head of counselling at South Yorkshire police force, says that all are assessed with the CapnoTrainer. “I would say that about 10 per cent show up as having low carbon-dioxide levels as a result of poorly regulated breathing, ” he says. “They get instant feedback and we can quickly get them breathing properly. Often they are back to work in a few weeks.”

It’s an area that is still under-researched and until large trials demonstrate a firm link between carbon-dioxide levels and health, there will remain scientific sceptics. A large $500,000 trial measuring carbon-dioxide levels in stressed Japanese schoolchildren, due to begin next spring, will provide more definitive answers on whether breathing affects how we feel.

In the meantime, Professor David Peters, of the School of Integrated Health at the University of Westminster, who specialises in treating stress disorders, believes that carbon-dioxide levels are a phenomenon and worth pursuing. “The physiology is well established,” he says. “It’s clear that people who have been stressed or traumatised don’t have to be hyperventilating to have a breathing-rhythm disorder and low carbon dioxide. The CapnoTrainer device could be a useful tool, although it would be good to have trials directly comparing its effectiveness with standard treatments.”

For futher information contact: the Mindful Physiology Institute, set up by Dr David Beales to run educational programmes about breathing for health professionals and patients, www.bp.edu; and Physiotherapy for Hyperventilation, an organisation which has practitioners around the UK who specialise in breathing problems, www.physiohypervent.org

Every breath you take . . .

How you breathe has an impact on your health, and not just because it affects the carbon-dioxide levels in your blood (see main story above).

Some studies have indicated that bed-wetting in children may be linked to breathing problems, such as an obstructed airway at night-time. The reasons are not yet understood.