Big lungs = a longer breath-hold?

1. How much does lung volume really matter?

First: yes, larger lungs can be an advantage when holding your breath.

Our oxygen reserves are held mainly in three places:

In the lungs, as part of the air we have breathed in.

In the blood, mostly bound to haemoglobin.

In the muscles, bound to myoglobin.

During an apnea, the body has to make do with these limited reserves.

A larger lung volume can therefore increase the amount of oxygen available.

But does that automatically mean a longer breath-hold?

No. How quickly the body uses its oxygen is just as important.

A scientific review by Elia and colleagues (2021) describes breath-hold ability as the interplay of oxygen storage, oxygen conservation and training experience.

Source: Elia et al., European Journal of Applied Physiology, 2021.

2. An interesting finding from the research

That scientific review describes a study in which breath-hold time was compared at different levels of lung filling.

The results:

The study involved seven trained freedivers performing dry static apnea. A statistically significant difference between these two conditions was not separately demonstrated.

In that study, the higher lung filling was associated with a longer breath-hold.

This shows that lung volume is by no means unimportant.

But these results do not mean that everyone with larger lungs can automatically hold their breath for longer.

Individual performance also depends on other physiological factors and on training.

Source: Overgaard et al. (2006), summarised in Elia et al. (2021).

3. Relaxation: less unnecessary muscle work

Freediving is not only about storing as much oxygen as possible.

It is also about avoiding unnecessary use of energy.

When you are tense, you often recruit muscles that the movement or the position does not actually require.

In static apnea training in particular, a calm, relaxed body position can help reduce unnecessary muscle work.

Even so:

Relaxation is not a guarantee of a longer or a safer apnea.

It is one part of good preparation, not a substitute for technique, training and safety measures.

4. Your body has its own way of saving oxygen

Have you heard of the diving response?

This physiological reflex occurs in humans while holding the breath, and it can be strengthened by contact between the face and the water.

Its most important responses include:

Bradycardia: heart rate can fall.

Peripheral vasoconstriction: blood vessels in certain regions of the body narrow, so blood flow is redistributed in favour of the organs that are vital.

These responses help the body work with its limited oxygen reserves.

In trained freedivers, the diving response can be more pronounced than in untrained people.

That does not mean trained freedivers are protected from a lack of oxygen.

Source: Patrician et al., Frontiers in Physiology, 2021.

5. Why experience and technique matter so much

Two people with a similar lung volume can reach very different breath-hold times.

One reason is training experience.

In freediving we learn, among other things:

To move more efficiently.

To notice unnecessary muscle tension.

To make better sense of physical sensations.

To shape the training load in a sensible way.

How you relate to the urge to breathe also plays a part.

That urge is driven largely by the rising level of carbon dioxide in the body.

Important: the urge to breathe is not a reliable indicator of how much oxygen is still available.

Hyperventilation in particular can delay the urge to breathe without protecting you from a dangerous lack of oxygen.

Training should therefore never be aimed at suppressing warning signals at any cost.

Source: Divers Alert Network – Freediving Safety Awareness.

6. What this means for your training

Perhaps you do not have the largest lung volume.

Perhaps you cannot yet hold your breath for very long.

That does not mean you have already reached your potential.

Instead of focusing only on your personal best, it is worth developing several areas:

Technique. Efficient movement helps you avoid unnecessary effort.

Relaxation. Good body awareness can help you reduce surplus muscle tension.

Training structure. Load and recovery belong together.

Experience. Over time you learn to understand the body's responses and to place them in context.

Safety. Progress should never come at the cost of your health.