diuresis in immersion

In your experience as a diver, even if you're still a beginner, you've surely had the opportunity to experience a sensation that's very common among divers: an irresistible urge to urinate during and after a dive, a sensation that, depending on the circumstances, can become a real nuisance. This is called diuresis during diving.

In case you've wondered why this happens (which by now you've probably noticed is a widespread phenomenon that doesn't just happen to you, but is very common), this article provides a brief explanation of its causes.

What happens is that, during exposure of our body to a hyperbaric environment (immersion), two simultaneous physiological phenomena occur: a concentration of blood volume (hypervolemia) in the central area of the torso at the expense of the extremities, along with peripheral vasoconstriction, which is accentuated when you submerge in cold water. The combined effect of this is an increase in blood pressure (BP), which the body tries to compensate for by increasing kidney function, excreting water and sodium through urine production (diuresis).

This increase in diuresis during immersion must be kept in mind, since the hemoconcentration that occurs as a result of dehydration (loss of fluids) in the body is one of the factors that most favor the appearance of decompression sickness (DCS).

TIPIn light of all the above, the guideline we should adopt as a safe diving practice consists of Stay well hydrated before and after immersion, to compensate for urinary losses. Remember that proper hydration is as important as taking the safety break (5m / 3 min).