How Does Breathing Affect Your Brain?

If you live to 80, you will take up to a billion breaths in the course of your life, inhaling and exhaling enough air to fill about 50 blimps. We take 20,000 breaths a day to fuel our cells and tissues, and to rid the body of carbon dioxide that builds up as a result of cellular metabolism. If you stop breathing, you will die within minutes.

We tend to take it for granted. Breathing is a miracle. Our breathing rate can change very quickly in response to stress or arousal. You may have never noticed how your breathing changes to accommodate other behaviors, because breathing is so seamless with them. Ancient meditative traditions show how breathing can influence your state of mind.

Researchers have begun to understand some of the underlying neural mechanisms of breathing. The network of neurons in the brainstem were identified in the 1980's. The discovery has given rise to investigations into how the brain integrates breathing. Researchers have found evidence that breathing can influence activity in a wide swath of the brain.

According to Jack L. Feldman, a neuroscientist at the University of California, Los Angeles, breathing has a lot of jobs. It has to be coordinated with all the other behaviors because we are constantly changing our posture.

Each breath a symphony of lung, muscle, brain

Your lungs fill with oxygen-rich air when you breathe and it diffuses into your bloodstream. The walls of the lungs are called alveoli and contain 500 million tiny sacs. The total surface area of this interface is less than a racquetball court and less than a one-bedroom apartment in San Francisco.

Humans pack a lot of surface area into our chests. The amount of gas exchanged per second is determined by the surface area.

The lungs can't do it on their own. The sacks are limp. The lungs have to be pumped to make this work. The muscles at the bottom of the chest are contracting when you breathe in. The intercostal muscles between the ribs help the rib cage move up and down. If you have ever had the wind knocked out of you by a blow to the stomach, you know all about the intercostal muscles.

These muscles are not Contracted at rest. When the lungs deflate and the muscles relax, exhalation is passive. Different sets of muscles contract during an exercise.

The brain orders the muscles that control breathing. It took a long time to find those brain signals. The doctor who noticed that gladiators whose necks were broken above a certain level were unable to breathe was the one who first pondered their source. In the 1930s, a British physiologist showed that the brainstem of a goldfish continued to produce electrical activity, which he believed to be the signal behind respiration.

The location of the brainstem respiratory-pattern generator remained a mystery until the late 1980s, when researchers narrowed it down to a network of about 3000 neurons. The preBtzinger Complex is now known as the preBtC. The muscles that control breathing are directly related to the electrical activity that occurs in the Neurons there.

Some people have thought Btzinger must have been a famous anatomist. He suspected a colleague was about to claim the discovery for himself, so he came up with the name. The brain region would be named after the wine that came from Btzingen, Germany. The others agreed and the name stayed. People are just as weird as scientists. We have a lot of fun doing this.

Pinpointing breath’s rhythm setters

Understanding how the breathing rhythm is generated by the preBtC is one of the areas of research that has been done by the author. The work laid the groundwork for his lab to investigate how the brain organizes the interplay between breathing and other behaviors.

One of the more interesting examples is sighing. A long, deep breath can convey many feelings. We humans aren't the only ones who sigh, and it might be because sighing has an important biological function. Humans sigh every few minutes and each sigh takes in more air than a normal breath. It is thought that this helps pop open collapsed alveoli, the tiny chambers in the lung where gas exchange occurs. Hospital ventilators that are programmed to include periodic sighing have been shown to improve lung function.

Four small populations of neurons were identified as being responsible for generating sighs in rodents. Two of the groups of neurons are located in a brainstem region near the preBtC, and they send signals to the other two groups. The rats stopped sighing when the researchers killed the preBtC neuron. The rats sighed ten times more when scientists injected the neuropeptides. Four groups of neurons form a circuit that tells preBtC to stop breathing and order up a deeper breath.

The preBtC has a role to play. Kevin Yackle is one of the people who collaborated with Feldman on the sighingpaper. Humans can't hear the high-pitched cries of newborn mice. Yackle, who is now at the University of California, San Francisco, says that there are many cries at regular intervals. He says there's a slower breathing rhythm and a faster vocalization rhythm.

The researchers went backwards to figure out how this works. The intermediate reticular oscillator (iRO) is a cluster of cells in the brain that are 888-609- 888-609- 888-609- 888-609- 888-609- The researchers found that killing or stimulating iRO neurons removes the ability to vocalize a cry and increases the number of cries.

The researchers were able to see the cells firing in a regular pattern. The preBtC breathing rhythm is similar to the cries in the animal.

Experiments suggest that iRO neurons help integrate vocalizations with breathing by telling the preBtC to make tiny inhalations that interrupt exhalation, allowing a series of brief cries to fit neatly within a single exhaled breath. Rhythmic crying doesn't come from a series of exhalations but from one long exhalation with several interruptions.

The findings have implications for understanding human language. Yackle says that the number of syllables per second is within a narrow range. He suggests that it might be due to the need to coordinate vocalizations with breathing.

Setting the pace in the brain

Recent studies suggest that breathing can affect a person's performance in a lab test. A person's ability to detect a faint touch and distinguish three-dimensional objects can be influenced by where they are in the cycle of inhaling and exhale. People tend to inhale just before a cognitive task, and doing so improves performance. It is only breathing through the nose that has the effects, while breathing through the mouth doesn't.

One idea focuses on the electrical activity in the brain. For decades, some scientists have argued that these waves reflect communication between brain regions that are far away from each other. They could be, for example, how the brain integrates sensory information processed separately in auditory and visual parts of the brain to produce what we see as a seamless perception of a scene. It has been difficult to prove that such activity could be the basis of consciousness.

Evidence shows that breathing may set the pace. The breathing rhythm influences waves of activity in the hippocampus, a region critical for learning and memory. The electrical activity of the hippocampus increases and decreases at a consistent rate during wakefulness. All animals that have been studied have a theta rhythm.

Adriano Tort and his colleagues at the Federal University of Rio Grande do Norte in Brazil noticed that their electrodes were picking up another rhythm, a slower one with about three peaks per second, similar to a resting mouse. They initially thought it was an artifact because of the animal's movements. They were able to prove that the respiration activity was real and that it acted like a metronome to set the pace for the theta.

Similar findings were reported in humans by Zelano and colleagues. The researchers used data from the brains of patients who had surgery to monitor their seizures and found that natural breathing synchronized with the brain regions that play a role in emotional processing. The effect diminished when the researchers asked the subjects to breathe through their mouths.

Zelano and colleagues found that the respiration rhythm can affect people's performance on emotional tasks. In one experiment, they asked subjects to identify the emotion expressed by people in a set of photos by monitoring their respirations. When the photo appeared as they took a breath, subjects were quicker to identify fearful faces. In a different test, subjects were able to remember if they had seen a photo before. The effects were stronger when subjects breathed in.

The respiratory rhythm can be synchronized between brain regions. In one study, scientists found that the respiration rate is related to the activity of the hippocampus and the prefrontal cortex. In a paper published earlier this year in Nature Communications, Karalis and Sirota suggested that this synchronization could be used to make long-term memories. It is thought that memories are formed in the hippocampus before being transferred to the cortex for long-term storage.

There may be important links between brain function and respiration, but more work needs to be done to connect the dots. He says the evidence shows that breathing affects brain activity. There is a challenge in figuring out what that means.

Controlled breath, calm mind?

For thousands of years, yoga and other ancient meditation practices have used controlled breathing as a way to influence their state of mind. Researchers have become more interested in the biological mechanisms of these effects and how they might be used to help people with anxiety and mood disorders.

Helen Lavretsky, a psychiatrist at UCLA, said that one challenge was to separate the effects of breathing from other practices. She says it's difficult to distinguish what's most effective when you're doing a multicomponent intervention. Many people attach the cultural and spiritual component to the practice.

Lavretsky has been researching how different types of meditation affect the brain and immune function for a long time. She has found that meditation can help older people with mild cognitive impairment, a condition that can lead to Alzheimer's disease and other types of dementia. She wants to investigate if the breath control methods alone can help.

Lavretsky, who is also a certified yoga instructor, is researching how to avoid prescription drugs. With more research on which breathing techniques work best for which conditions and how they might be tailored to individuals, she believes breathing exercises might be a good alternative. She says that everyone has a tool and needs to learn how to use it.

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