Breathe Like It Matters

Why your respiratory tract determines your performance at rest.

Intro

Some performance blockers are obvious or overly present. Others are hardly noticeable or would never be interpreted as such. I remember situations where I was sitting quietly in front of a screen, in a meeting, or in bed at night. Although I felt no physical stress or urgency, I felt an inner restlessness, slight exhaustion, and a lack of clarity. For a long time, I considered this to be “normal”. Later, I realized that my body was in work mode, even though I felt far removed from it. It became clear to me that the trigger was as mundane as it was ever-present: my breathing.

What Science Says

Mouth breathing is considered harmless; however, I discovered that it has a clear physiological disadvantage, especially during periods of rest. Recent studies have shown that mouth breathing is associated with a higher heart rate, reduced CO₂ tolerance, and lower parasympathetic activity, which can result in increased stress levels and impaired regulatory capacity. A 2021 study showed that mouth breathing affects activity in prefrontal brain areas responsible for attention, working memory, and cognitive control. The consequence isn’t an acute loss of performance, but a gradual loss of efficiency – concentration becomes more unstable and mental fatigue sets in earlier.

Nasal breathing consistently counteracts these effects. The nose filters, warms, and humidifies the air. But most importantly, it produces nitric oxide, a gas that dilates blood vessels, improves blood flow to the lungs, and increases oxygen availability. At the same time, the autonomic balance shifts in favor of the parasympathetic nervous system. A 2023 study showed lower diastolic blood pressure, higher heart rate variability, and a faster return to a regulated state. These effects occur after just a short period of acute nasal breathing, without training or technique, solely through the breathing route.

It’s important to note that during intense physical activity, mouth breathing plays a functional role by allowing for higher ventilation and faster gas exchange. However, this is precisely where the widespread misconception about everyday breathing originates. We often breathe as if we were stressed, even when we are sitting, walking, reading, or falling asleep. Research is clear that, in calm situations, nasal breathing is more efficient for the body and brain.

Small Change

From my perspective, a simple but effective adjustment is this: Whenever possible, you should consciously breathe through your nose, especially in calm situations such as when walking, sitting, working, or falling asleep. Breathing should be mindful, not forced or overly controlled. Optionally, you can reinforce this pattern with a daily 60-second “nose check”, during which you breathe in and out calmly, without any goal or rhythm. It’s only about to establish nasal breathing, not to perfect a technique. 

Compounding Effect

Long-term effects develop cumulatively. Studies show that regular daily nasal breathing results in less physiological stress and more stable attention. It also leads to a measurably higher heart rate variability, an indicator of better autonomic regulation. Over weeks – not just days – you will notice effects that are difficult to isolate in everyday life, such as greater mental clarity, less irritability, and a calmer transition to sleep. The body distinguishes between activity and rest, and that is precisely what true performance is. 

Let’s try it!

Today, when I think about the situations described at the beginning, they seem different. Not because they have changed, but because I have. Breathing is not a skill that you have to master. Conscious breathing is more of a signal to your body, the nervous system, and state of mind.

Your next moment of calm is sure to come. Maybe you’re sitting quietly in front of a screen right now. Maybe it’s late at night in bed. Either way, now is a good time to close your lips and let your nose do the rest of the work.

In addition to your breathing, a glass of water and your first coffee can also give you a boost for the whole day. Learn here how a glass of water is more than just a fuel for the day ahead. Learn here how delaying your morning coffee can boost your energy, focus, and sleep.

For a deeper insight:

Mapelli, M. et al. (2025). Nasal vs. oral breathing strategies in healthy individuals during cardiorespiratory exercise testing (BreathWISE).

Leveque, M. et al. (2025). Effect of oral versus nasal breathing on muscular performance, muscle oxygenation, and post-exercise recovery.

Bayrak, Ö. et al. (2024). Effects of nasal and oral breathing on respiratory muscle and brain function: A review.

Watso, J. C. et al. (2023). Acute nasal breathing lowers diastolic blood pressure and increases parasympathetic contributions to heart rate variability.

Cavaggioni, L. et al. (2022). Effects of a nasal breathing protocol on physical fitness and pulmonary function in young basketball players.

Jung, J.-Y. et al. (2021). Effect of oral breathing on cognitive activity using functional brain imaging.

Stanford University / Huberman Lab. Nasal breathing and autonomic regulation.