When a body is immersed in water, changes in hydrostatic pressure causes blood which would normally pool in the legs and arms to move to the chest. This increases the central blood volume and can cause fluid to leak into the lungs.

People who suffer high blood pressure (hypertension) and other cardiac conditions are particularly susceptible to IPE due to increased alveolar pressure.

Breathing through a snorkel or a diving regulator can generate resistance to inhalation and can result in negative thoracic pressure, creating a vacuum phenomenon which can draw fluids into the lungs.

Lying in a prone position whilst immersed can increase the risks of IPE (although scuba divers' symptoms can arise with the vertical posture during ascent).

Strenuous exercise and feeling anxious can increase the risk of an IPE

Older people are more susceptible to IPE and it is overrepresented in women.

Cold water causes vascular constriction which will increase the pressure in alveolar capillaries and increase the risk of IPE, however IPE does occur in warmer waters as well.

Overhydration has an additive effect on the increase in alveolar capillary pressure resulting from immersion and can increase the risk of an IPE occurring.

Tight wetsuits can result in an increase in capillary pressure making a person more susceptible to IPE.

If a diver develops IPE at depth and then ascends, they are at risk of unconsciousness as the partial pressure of oxygen decreases on ascent in addition to the postural change.