Breath holds and nose breathing

ByLifefit Physio

Nasal Breathing, Oxygen Efficiency, and Performance

Recent developments in breathing science highlight the importance of nasal breathing and controlled breath holds as tools to improve oxygen efficiency and endurance performance. This approach is strongly associated with the work of Patrick McKeown, author of The Oxygen Advantage, whose research focuses on optimising breathing patterns rather than simply increasing air intake.

Nasal Breathing and Oxygen Utilization

A common belief in exercise physiology is that at high intensities the nose cannot deliver enough air to meet oxygen demands, making mouth breathing necessary. However, current evidence suggests that the limiting factor at higher intensities is not the amount of air entering the lungs, but rather how efficiently oxygen is:

  • Bound to haemoglobin

  • Transported in the blood

  • Delivered and utilized by working muscle cells

Nasal breathing has been shown to improve this oxygen transport system. To gain these benefits during exercise, nasal breathing must be practiced consistently—not only during training, but also:

  • At rest

  • During sleep

  • While walking

  • During daily activities

Establishing nasal breathing as the default pattern improves overall breathing efficiency, making it possible to maintain nasal breathing even as exercise intensity increases.

Assessing Breathing Patterns: The BOLT Test

Breathing efficiency can be assessed using the BOLT (Body Oxygen Level Test). This test provides an indirect measure of carbon dioxide tolerance, which closely reflects breathing control and efficiency.

How the BOLT test is performed:

  • The test is done at rest, not after exercise.

  • Breathe normally through the nose for a short period.

  • Take a normal breath in through the nose, then a normal breath out.

  • After the exhale, pinch the nose and start timing.

  • Hold the breath until the first clear urge to breathe appears.

  • Stop the timer at this point.

A correct measurement is confirmed if normal breathing can resume afterward without gasping or taking an exaggerated breath.

Nasal Breathing in Zone 2 and Zone 3 Training

Low- to moderate-intensity training (Zone 2 and parts of Zone 3) provides an ideal opportunity to reinforce nasal breathing. At these intensities:

  • Breathing should remain nasal throughout the session.

  • Breathing should be light, calm, and controlled—not deep or forceful.

  • If pace must be reduced to maintain nasal breathing, this indicates that the original training intensity was likely too high.

Consistent nasal breathing at aerobic intensities improves breathing efficiency and promotes better intensity control. Many athletes also report increased mindfulness and improved pacing during sessions.

Breath Holds and Simulated Altitude Adaptation

Short breath holds during low-intensity exercise can be used to simulate certain effects of altitude training. These breath holds temporarily:

  • Lower blood oxygen saturation

  • Increase carbon dioxide levels

These changes stimulate adaptations such as:

  • Increased red blood cell production

  • Improved oxygen delivery to muscles

  • Enhanced tolerance to elevated CO₂ levels

  • Better buffering of acidity (pH control)

  • Delayed transition from aerobic to anaerobic metabolism at higher intensities

How to Practice Breath Holds During Training

Breath-hold practice should only be performed at Zone 1 or Zone 2 intensity.

Guidelines:

  • During a 45–60 minute Zone 2 session, perform 5–6 breath holds.

  • Take a normal breath in through the nose, then a normal breath out.

  • After the exhale, hold the breath and continue jogging or cycling.

  • Resume breathing when a strong but controlled urge to breathe appears.

  • Normal nasal breathing should return quickly without gasping.

This practice reinforces oxygen efficiency while maintaining aerobic control.

Key Takeaway

Improving endurance performance is not solely about moving more air, but about using oxygen more effectively. Nasal breathing and controlled breath holds offer practical tools to enhance oxygen transport, breathing efficiency, and aerobic resilience when applied consistently and at appropriate intensities.