“Breathe in through your nose and out your mouth”

I started running primarily because my older cousin, Nic, ran. He was one of the best high school runners in Georgia and the nation in the late 90s early 2000s.

Nic leading the field

I remember vividly the first time I got to run with him during Thanksgiving break when I was 14 years old. I learned a lot that day running with Nic. One thing I learned about was easy running.

Since my cousin had already run 9:19 and 4:19 in the 2 mile and 1 mile, respectively, I could only guess that his easy running pace must be around 5:00/mile.

I took off as fast as I could run, Nic called out from behind “what are you doing??” I told him I thought I needed to go that fast for his easy run, to which he replied “no, my team almost always goes slower than 7 minutes/mile on easy days.”

Once we slowed down, I decided to ask a question I had had for a while: “how should I breathe while I run?” My coach in middle school had told me to “breathe in through my nose and out my mouth.” To which my cousin replied: “no man, just breathe [in and] out of your mouth.” I couldn’t help but laugh a little.

Part of what made me laugh is I realized how I was overthinking something so simple. The same goes for breathing patterns.

The science behind respiration

Respiration allows for the exchange of two major gases of concern: oxygen and carbon dioxide. The energy demand created by the athletes effort will increase the demand of oxygen, and the energy created through metabolism will increase the production of carbon dioxide that must be expelled from the body. As our demand for oxygen and production of carbon dioxide increases, so does our respiration rate to both inhale the needed O2 and exhale the CO2 by-product. Brinkman and Sharma state it well below:

Should at any point the available oxygen supply not meet the necessary demand, aerobic metabolism will no longer be possible, and energy production will fail. Likewise, if carbon dioxide levels are allowed to accumulate without disposal, the blood will become more acidic, leading to cellular damage on a systemic scale, which may ultimately lead to organ failure or death. Neither outcome is desirable. To negate the constantly changing demands of the body, respiration is modulated to match its drive to the overall demand of the body.


At low intensities, this exchange will be less dramatic, allowing for slower respiration rates. At higher intensities, the CO2 production rate can become large enough that we may begin to hyperventilate (very fast breathing pattern) since carbon dioxide is the primary driver of respiration. CO2 has a partial pressure exchange rate that is about 20-25 times that oxygen, meaning small changes in CO2 production can drive larger changes in respiration.

A specialised centre present in the medulla region of the brain called respiratory rhythm centre is primarily responsible for this regulation. Another centre present in the pons region of the brain called pneumotaxic centre can moderate the functions of the respiratory rhythm centre. Neural signal from this centre can reduce the duration of inspiration and thereby alter the respiratory rate. A chemosensitive area is situated adjacent to the rhythm centre which is highly sensitive to CO2 and hydrogen ions. Increase in these substances can activate this centre, which in turn can signal the rhythm centre to make necessary adjustments in the respiratory process by which these substances can be eliminated.


What does this mean for us? Breathing patterns are involuntary, until we make them voluntary through conscious manipulation. Any conscious change to your breathing pattern can only be sustained as long as you are consciously manipulating it (go figure), and will inevitably return to involuntary control when you can no longer manipulate it (usually when the effort is high enough that you forget to control it and/or the CO2 production is ‘forcing your hand’).

Further, there isn’t an additional benefit for sustained conscious control, as I’ve mentioned in a previous blog post any conscious control of an autonomic process will result in more oxygen consumption resulting in worse running economy.

Practical Indicators

I’ve gone on a lot of runs with a lot of runners over the years. Some of those runs were easy, others were time trials or races. I first developed an “ear” for breathing while racing. When trying to win a race, you’re looking for any indicators from your competition regarding their fatigue state. The rate of their breathing is one of those indicators.

When the anaerobic demand becomes quite high, you’ll hear an acceleration of respiration even up to a 1-1 inhalation/exhalation for each step. At that point you know that your competition is cracking (if they haven’t already fallen off your back). This hyperventilation is due to the large amount of CO2 being produced.

Depending on an athlete’s ability to hold a conversation during a run can also indicate their respiration rate as well as their effort. While beneath ventilatory threshold 1 (VT1) an runner can hold a fluid conversation. This is what you want during true easy running. As the amount of CO2 increases (due to intensity and metabolism of carbohydrate), so will our respiration rate and full sentences become more difficult. Around ventilatory threshold 2 (VT2) only a few words can be muttered at a time due to the respiration rate.

When pacing athletes during time trials I listen to the rhythm of their breathing. A sudden acceleration in respiration when I know that we’re already around VT2 cues me to slow down so that they can normalize their effort.

Dr. Jack Daniels speaks about breathing patterns in “Daniels’ Running Formula.” He talks about these patterns in relation to cadence. While I don’t fully agree with the method since the calculation is dependent upon cadence (which changes and is highly variable), some runners will naturally fall into this rhythm.

Most elite distance runners breathe with what’s called a 2-2 rhythm – taking two steps (one with the right foot, one with the left foot) while breathing in, and two steps while breathing out. Most good runners take about 180 steps per minute, so this gives about 45 breaths per minute.

Daniels, Dr. Jack. “Daniels’ Running Formula: 2nd ed.” p. 116

There are different rhythm versions like 1-2, 3-3, etc. but these patterns are naturally contingent on the oxygen demand and carbon dioxide production rather than a pattern to be aimed for (see discussion above).

Final Thoughts

There are probably certain breathing patterns that athletes may swear by. Regardless of this, it is primarily an involuntary process.

From a practical standpoint, and as a concession, I will say that I’ve seen some benefit from “resetting” my ventilation with a hard exhale to clear CO2. I’ve also used a large inhale to try to shake cramps that my diaphragm may be experiencing or to calm myself down if my pace/effort is too hard. If you find yourself hyperventilating with rapid shallow breaths, it may be useful to take these deeper breaths to reset, but more importantly it may be useful to slow down if you’re far away from the finish line.

Your breathing can teach you a lot about your effort. Use your natural patterns to learn more about appropriate intensities while you train and race.

Happy running!