Slow Breath, Deep Healing: The Quiet Science of CO₂
The science of carbon dioxide tolerance, the Bohr effect, and why the way you breathe might be the most underrated tool for healing and performance.
I would like to start by clearly stating that I do not believe you can simply "breathe all of your problems away." Nor do I feel that doing a specific breathing technique or practice will heal or cure disease. What I do believe—based on very sound science—is that breathing better will improve the way your mind, body, and cells function. And with this improved inner system, the breath can help activate the body's own inner healing powers.
I've been thinking about this quite a bit lately, and the more I sit with it, the more it makes sense: carbon dioxide and oxygen not only drive our respiratory system, but they drive health and healing.
The CO₂ Bodysuit Experience
A couple of weeks ago, I was at a bike event and came across a recovery booth offering a CO₂ bodysuit "to optimize health and rejuvenation." Intrigued, I signed up for a demo. "Slide it on over your clothes, make sure it's air-tight around the ankles, wrists, and neck, have a seat, lounge back and get comfortable." He zipped me up, connected a hose to the suit, and began to suction out all of the air. I felt like a package getting vacuum-sealed—but in a good, comfortable way.
Next, he hooked up another hose connected to a tank of pure carbon dioxide. The vacuum became a bubble. My skin quickly began to feel flushed, warm, and tingly.
As I sat there for 15 minutes, I didn't notice a shift in my breathing, but I felt as if I had more air. The theory is that your body absorbs carbon dioxide through the skin (transcutaneous absorption), which permeates into the blood, increasing carbon dioxide levels and creating a mild state of hypercapnia. This enhances oxygen delivery throughout the body via the Bohr effect. As a result of the carbon dioxide absorption through the suit, your blood and cells become much more oxygen-efficient. It sounds wild, but the research is compelling.
The Science Behind CO₂ and Healing
In 2017, Japanese researchers published a study titled "Optimization of antitumor treatment conditions for transcutaneous CO₂ application: An in vivo study" (Ueha et al.). They investigated what would happen when carbon dioxide was applied to the skin overlying a tumor site in mouse models using a CO₂-containing hydrogel. They found something remarkable: under optimized conditions (sessions longer than 10 minutes), tumor volume was significantly reduced.
This was achieved with a carbon dioxide gel applied directly to the skin, though the underlying principle of transcutaneous CO₂ absorption is considered similar to methods using CO₂ bodysuits or baths. Tumors often thrive in low-oxygen environments—a state called hypoxia. Transcutaneous CO₂ does the opposite: it increases local blood flow, improves oxygen delivery to the tissue, and leverages the Bohr effect so red blood cells unload oxygen more efficiently in the target area. As a result, hypoxia in the tumor decreased, oxygenation improved, and tumor size was reduced.
As a physiotherapist and breathwork practitioner, the concept of oxygen supporting healing is not novel. Many theories—both modern and ancient—discuss breathing slower and deeper, lowering the respiratory rate, and creating a subtle influence on blood pH. Breath-holding practices have been used for thousands of years to create a more significant and acute impact on inner physiology—stimulating energy, efficiency, oxygen utilization, and healing from within.
If the research on transcutaneous carbon dioxide therapy is valid—and it appears to be pointing in a promising direction—then wouldn't it make sense that we could create similar positive effects by incorporating intentional breathing practices into our lives?
I believe this is not only plausible, but potentially necessary for optimal health. The main advantage of breathing better is that it is always accessible and among the safest practices available. Even before experiencing the CO₂ bodysuit, I had long believed that an oxygen-rich internal environment is far more effective at combating inflammation, stress, cancer, and disease.
To be very clear: I am not claiming that you can breathe your way to perfect health. But adding breath awareness, intentional breathing practices, and dedicated time throughout the day holds great potential value as a preventative health tool. No fancy bodysuit required. I do appreciate the innovation of a passive tool that can support many people, but I've always been an advocate of active engagement with health—though doing both is perfectly reasonable.
How to Adjust Your Breathing for Better CO₂ Levels
So how do you adjust your breathing to improve carbon dioxide levels?
Improve the function and efficiency of your breathing.
Slow down your respiratory rate (which goes hand-in-hand with improving function).
Incorporate breath-holds into your practice and daily life.
The first two likely make sense, but what about breath holds?
When you hold your breath, CO₂ rises—momentarily until you return to breathe. But with these little spikes of carbon dioxide, your body responds with vasodilation, nitric oxide release, improved oxygen delivery, and various anti-inflammatory effects. (Sounds a lot like the claims of benefit of the CO₂ bodysuit).
A Quick Breath Test
Exhale and hold for 10 seconds. At the end of the hold (before inhaling), blow out a little more air like extinguishing a candle, then hold another 5 seconds. Blow out an exhale again, hold another 5 seconds—again and again until you can't anymore and you need to breathe in. Good job. Recover your breathing and come back to relaxation.
What did you feel? What did you notice? How long did you hold? How many "candles" did you blow out? Continue to play with this.
The Modified CO₂ Tolerance Test
Bringing it back to the CO₂ suit. This passive modality increases the level of CO₂ in the body. The principles I shared above do the exact same thing. They challenge the inner nature of your physiology and create an opportunity for adaptation and growth.
You're building a relationship with the intrinsic urge to breathe—which comes primarily from a rise in carbon dioxide (not just a drop in oxygen), and other variables.
Even when you're not breathing, your body keeps "breathing." Your heart pumps oxygen-rich blood everywhere, and in the mitochondria of all 30 trillion cells, oxygen is used to produce energy. Carbon dioxide returns to the bloodstream and rises until you exhale.
Closing the "exhaust" (holding after exhale) lets CO₂ accumulate quickly across every cell. Eventually you breathe to restore balance. Blood pH normally sits between 7.35 and 7.45—slightly alkaline, favoring an oxygen-rich environment. Cellular function and human health thrive in this state. But the ideal balance includes a little extra CO₂. Your oxygen saturation is usually already near maximum even when CO₂ is driving the urge to breathe.
Mild hypercapnia is where the magic happens: the body becomes more oxygen-efficient—not necessarily richer in oxygen volume, but far better at moving and utilizing it. This is a secondary but powerful byproduct of efficient breathing.
The first two points—functional and slow breathing—have a similar but more subtle effect on CO₂. By breathing slightly deeper and longer than usual, you naturally retain a little more CO₂. The benefit here is that you breathe thousands of times a day, which gives you thousands of opportunities to engage with your breath and influence your physiology and healing state.
Be mindful though: making minor changes to breath can create a big stimulation of mind, body, and nervous system. Meet yourself where you're at.
Try the Breath Test: The Modified CO2 Tolerance Test
Daily Breath Patterns
A common breath pattern I aim to hit on an all-day, everyday basis is as follows:
4-second inhale, 6-second exhale
3-second inhale, 1-second hold, 6-second exhale
3-second inhale, 7-second exhale
We take 20,000–25,000 breaths a day. Changing the baseline of every breath creates compound-interest-level impact on physiology.
Purpose and Practice
I feel that before the practice one needs purpose. Practice without purpose holds minimal value.
There is an inner will within each human that holds super powers of energy and effectiveness. Finding purpose aligns this inner will to be on board with the practice.
The purpose is health. The purpose is growth. The purpose is allowing the natural and brilliant human mechanisms of life and consciousness to rise through you with as little obstruction as possible.
The daily foundation is breath awareness: deepen into the lower diaphragm, allow subtle expansion in the upper ribs and back, let the spine move gently with each breath. Slightly suspend at the top, extend the exhale a little deeper, press out the bottom, and repeat a cycle that serves your inner chemistry as fully as possible. This is an all-day, every-day practice.
The breath activation for energy, stimulation, growth, and adaptation are the ones inspired by methods like Wim Hof, Erwan Le Corre's BreathHoldWork, or Buteyko-style breathing—with emphasis on expanded breathing, accelerated pacing, nervous system regulation, and breath holds.
For more on these practices, check the videos on my YouTube channel.
The Mirror Within
So here we are.
The CO₂ suit was a mirror. An external reminder of something we already carry within.
Breath is the primary bridge—the fastest way to align the inner weather with whatever storm or stillness is outside. This is dynamic allostasis in real time: consciously meeting the moment, matching internal energy to external reality, whether the world is crashing waves or soft wind. The nervous system already knows how to do this unconsciously.
The practice is to make it deliberate. Pause right now.
Take one slow breath in through the nose. Let the exhale be longer than the inhale. Feel the subtle drop in your shoulders. Notice the small buzz under your skin, the cells quietly waking up. That's not imagination. That's your physiology saying yes.
When we stay with the breath—when we stop living only in the head—we lower allostatic load and raise something else: presence, vibrancy, calm that doesn't need to be earned.
JT