Slow your breathing and use your nose

Our impetus to breath is rising levels of carbon dioxide(CO2) in our blood stream, NOT falling levels of oxygen(O2). As CO2 rises above our idiosyncratic tolerance level we inhale to swap out CO2 for O2 via the lungs, then we exhale the CO2. Our CO2 tolerance is set by how frequently we breath AND what we breath with….mouth or nose.

If you are at rest or doing a low-effort activity and you breath with your mouth you are off-loading a lot more CO2 than a nose breather at the given workload, and your CO2 tolerance will be lower. Likewise, if you breath frequently(north of 10x minute) while at rest or at low activity levels, you are off-loading an excessive amount of CO2. So slow your breathing down and start breathing with your nose for most things.

How to improve endurance….

While Working Out:

Breath through your nose while you are doing your cardio! Wether you are walking, running, hiking, biking, don’t exceed a pace that requires you to start mouth breathing. It could take anywhere from 4-6 weeks to get back to your normal pace while only nose breathing. But, you will get back to your normal pace/distance and then some!

Specialized Breathwork Training:

While walking or running (please don’t do this on a bike!) inhale through your NOSE and hold your breath for a given amount of steps, then slowly resume NASAL breathing for 5 breath cycles (inhale/exhale). Then repeat that again for 5 minutes.


Stop if you are uncomfortable or dizzy.

Hold your breath only for a duration that will allow you to comfortably recover from the breath-hold within 5 breath cycles. Ie. If you are snorting all over the place after holding your breath for 15 steps, maybe reduce the breath-hold to 10 steps.

Slowly increase the amount of time you do this. I have done for 20-30 minutes hiking.

More Breathwork Training:

Find a comfortable place where you will not be disturbed and have a seat.

Start with a 3 second inhale, 6 second breath-hold, 3 second exhale (NOSE not mouth!)

Increase or decrease this according to your comfort level at a ratio of 1:2:1 (ie. 6 second inhale, 12 second hold, 6 second exhale)

The idea is to be able to decrease yoyr total number of breath cycles per minute.


This is not a breath holding contest.

Stop if you get dizzy or uncomfortable.

What I do:

1st gear: Nasal Inhale / Nasal exhale. Long distance, steady state pace.

2nd gear: Nasal Inhale/ Mouth exhale. Uphill or sustained increase in my pace.

3rd gear: Mouth inhale / Mouth exhale. Maximum effort.

Goal - Return to and remain in 1st gear as long as possible.

Some notes:

It is perfectly functional and normal to use your mouth to breath under some circumstances. Moderately high to extreme amounts of exertion absolutely require you to mouth breath. And you can use mouth breathing techniques to your advantage…but that is for another post.

The Bohr effect….

A little physiology follows….but it is brief.

Carbon Dioxide = CO2

Oxygen = O2

In the context of exercise, we are producing an elevated amount of CO2. As we transport O2 to the muscular system during exercise, hemoglobin drops off the O2 and then clears out the CO2 from the muscles, bringing it back to the lungs for exhale. Stay with me. The hemoglobin will drop off the O2 in proportion to the amount of CO2 that is available to be cleared out. If there isn’t a lot of CO2, the O2 passes on by without getting dropped off. Hence the Bohr Effect. The higher the concentration of CO2 in a muscle the more O2 that will be delivered to said muscle! That is to say, the higher your CO2 tolerance, the more efficient your body will be at delivering O2 to the muscles that need it.

Why does this improve our endurance……muscle fiber type and fuel type, an over-simplification

For the sake of this post let’s dived our muscle fibers type into Type 1 (slow twitch endurance) and Type 2 (fast twitch power). Training with nasal breathing at increasingly higher workloads will increase the amount of work our Type 1 fibers can handle, which improves endurance.

We carry around an almost infinite amount of energy in the form of fat (some more infinite than others). However, we have a relatively limited supply of glucose. Type 1 fibers prefer fat, Type 2 fiber prefer glucose. If you train with nasal breathing you will use a larger ratio of fat to glucose, which translate into improved endurance.