Han and colleagues investigated the influence of pre-hydration levels on circulating bubble formation for scuba divers and evaluated the appropriate volume of water intake for reducing the risk of decompression sickness (DCS). They demonstrated that pre-hydration with 30% of the recommended daily water intake before scuba diving effectively suppressed the formation of bubbles after diving and decreased the risk of DCS. Their study recently appeared in the Journal Int. J. Environ. Res. Public Health.
Decompression sickness, also called generalized barotrauma or the bends, refers to injuries caused by a rapid decrease in the pressure that surrounds you, of either air or water. It occurs most commonly in scuba or deep-sea divers, although it also can occur during high-altitude or unpressurized air travel.
DCS results in the production of venous gas emboli from the release of inert gas that may evolve in the tissues or blood due to super-saturation during decompression. Bubbles excessively generated in the blood and super-saturated tissues potentially cause severe neurological damage. It is considered a pathological condition caused by intravascular and extravascular gas bubbles, and its symptoms range from mild discomfort, such as painful joints and skin rashes, to neurological consequences including cognitive impairment, sensorimotor dysfunction, and death.
Previous study suggested that pre-dive oral hydration can be an easy means of reducing the risk of DCS. However, the appropriate level of hydration was not provided in the study. Thus, Han and colleagues now investigated the appropriate volume of hydration before scuba diving contributing to the reduction of circulating vascular bubbles using a Doppler device.
They classified twenty scuba divers into four groups according to the volume of water taken in before scuba diving as follows: no-water-intake group (NWIG), 30%-water-intake group (30WIG), 50%-water intake group (50WIG), and 100%-water-intake group (100WIG). Then, they measured the circulating bubbles using movement status by Doppler on the right and left subclavian veins and precordial regions at pre-dive, post-dive, and 30 min after diving to a depth of 30 m for a duration of 25 min at the bottom.
They found that drinking 30% of daily water intake before scuba diving contributed to a reduced Spencer grade. Most of the participants who drank 30% (0.69 L) of daily water intake 2h before scuba diving showed the lowest (I) or the second-lowest (II) Spencer grade (as shown in Table 1).
From these results, one can inferred that drinking 30% of daily water intake before scuba diving effectively removed the formation of bubbles after diving and facilitated the recovery after diving by reducing bubbles in the body.
Moreover, their study confirmed that 30% of water intake before diving is a suitable way to prevent DCS. On the other hand, drinking 100% of daily water intake before diving showed similar bubble grades to non-water intake, which further facilitated the formation of bubbles in the body. There are 6–7 L of water in the body. However, the higher the water retention amount, the higher the possibility that the bubble retention amount increases. That is, it is good to consume water only as much as the amount to be dehydrated, but as a result of analysis in this study, the amount was 30%. This means that 30% of water intake before and after diving is very important in smoothing out the air bubbles already in the blood vessels.
Featured image credit: Getty Images
Reference: Han, K.-H.; Hyun, G.-S.; Jee, Y.-S.; Park, J.-M. Amount-Effect of Water Intake before Scuba Diving on the Risk of Decompression Sickness. Int. J. Environ. Res. Public Health 2021, 18, 7601. https://doi.org/10.3390/ijerph18147601
Note for editors of other websites: To reuse this article fully or partially kindly give credit either to our author/editor S. Aman or provide a link of our article