Smoking and diving should not go hand in hand

Diving is a fascinating sport that requires physical fitness, mental clarity and healthy lungs. At the same time, smoking is a widespread habit that significantly impairs precisely these requirements. What many recreational and sport divers underestimate is that smoking not only increases the general health risk, but also poses a direct threat to diving safety.

Of course, you can smoke, Captain Cousteau...

Chronic bronchitis, narrowed bronchi and air trapping

Regular smoking leads to chronic bronchitis – a permanent inflammation of the bronchial slime membrane (mucosa). This inflammation narrows the airways. The narrowed bronchi contribute significantly to what is known as air trapping: During inhalation, the bronchi are stretched by the expanding lungs and open slightly – during exhalation, however, the narrowing of the airways intensifies so that the air cannot escape completely. This leads to air being trapped in the alveoli, known as air trapping, and hyperinflation of the lungs – a condition that can be life-threatening when diving.

Dynamic airway compression

Dynamic airway compression plays a special role here: when exhaling, the pressure in the chest increases, which can cause small airways to collapse – particularly in cases where the lung structure is already damaged. This phenomenon is independent of effort, meaning that it cannot be compensated for by increased breathing effort. This means that the diver cannot completely expel the air despite actively exhaling. This effect is more pronounced in smokers, as smoking damages the elastic fibres of the lungs – the forces that normally keep the small airways open. The result: increased air trapping and an increased risk of lung overinflation.

When diving, this can have fatal consequences: according to Boyle's law, the trapped air expands when surfacing due to the decreasing ambient pressure. The result can be overstretching and tearing of the lung tissue with a pneumothorax.

What is a pneumothorax?

A pneumothorax occurs when air escapes into the chest cavity (more precisely, into the pleural space) through a tear in the lung.

Normally, the lung is ‘stuck’ to the chest wall by the parietal pleura and the visceral pleura – similar to two wet window panes sticking together. This connection ensures that the lung expands with the chest when you breathe in. If air enters this space, this connection is broken – the lungs can no longer expand and collapse partially or completely.

The consequences of a pneumothorax can include chest pain, shortness of breath and, in extreme cases, life-threatening circulatory collapse if a valve-like mechanism causes more and more air to be forced into the pleural space by the breathing movements, creating excess pressure in the chest that clamps off the vessels leading to the heart, preventing it from maintaining circulation.

One pneumothorax – usually a lifetime diving ban

A pneumothorax can not only be acutely life-threatening for divers, but also has long-term consequences: anyone who has suffered a pneumothorax is usually no longer certified to dive. Even after surgical treatment, there is usually an increased risk of recurrence – and thus a permanent exclusion criterion from diving.

Conclusion: divers should refrain from smoking

If you want to dive, you need healthy lungs – and if you love diving, you should give up smoking. The potential risks range from chronic bronchitis to life-threatening pneumothorax.

The decision to quit smoking is therefore not only a question of general health, but also a central component of diving safety.