Person being on board a rescue boat in the tropics, there is nowhere to hide from the heat coming from all sides: from the direct solar radiation, the rays reflected from the mirror surface of the ocean, from the hot sun shell boats.
In the fight against overheating the body uses all safeguards and especially potovydelitelnuyu system that operates with maximum voltage. Water losses in the sun in the tropical zone of the ocean, sometimes reaching 740-810 g / h. However, with every drop of sweat lost by the increasing threat of dehydration. A paradoxical situation. On the one hand, the body must provide cooling by sweat, and the other — sweating increases dehydration, fluid loss because there is nothing to fill. However, there is a simple method by which to reduce sweating and at the same time to provide cooling of the body: just wet clothes outside water and it evaporates, will take on the cooling function pota.Chtoby test the effectiveness of this method, we conducted a pilot study during expeditions on research vessels in the 1964-1975 years. In each series of experiments, five subjects were in for three hours on the open deck. Performed hourly weighing on medical scales. The value of water losses determined from the change in body weight. Radiation temperature recorded on zacherchennomu globe thermometer. Studies have shown that people exposed to the sun at 45 — 50 ° (on the globe thermometer) loses 15 420 ml of fluid per hour (1.2 — 1.4 liters for three hours).
In the second series of experiments, the subjects were placed in a tent made of white nylon. This little shadow defense somewhat reduce water losses amounted to 230 + 15 ml / h.
In the third series of the subjects who were in the sun, dressed in a white knit shirt with long sleeves, water-soaked. As the drying clothing periodically moistened. When weighing revealed that sweat water losses decreased to 170 + 13 ml / hour. While being tested and teplooschuscheniya improved significantly. However, prolonged exposure to high temperatures all the measures used to reduce water losses though slow process of dehydration, but can not stop it. Thus, during the mnogosutochnyh experiments conducted in rescue boats and on the ship at the radiation temperature of 40-52 °, relative humidity of 80 — 96%, is for the first day the subjects lost an average of 2787 + 453 ml liquid.
Since the daily allowance of water was limited to 0.8 liters and not compensated vodypoter sweating, total fluid loss after five days of the experiment averaged 5674 + 560 ml. As a result of the subjects developed dehydration, which amounted to 8.0-8.5% of initial body weight. This was accompanied by heat oliguria. Daily urine output decreased from 1108 + 101 ml and 670-370 ml.
In addition, we observed a decrease in urine electrolytes. For example, on the fifth day of the experiment daily excretion of sodium decreased compared with the background from 121.32 + 15.73 to 15.3 + 3.4 mmol, and the chlorine content decreased almost 12-fold (from 162.8 + 17, 5 to 8.1 + 2.1 mmol).
Yet the body is not experiencing a sodium deficiency. This was evidenced by the stability of sodium in the blood throughout the experiment (320-350 mmol / L).
Although the changes were less significant kaliureza (potassium in daily urine decreased from 32.17 to 21.8 + 3.9 + 2.0 mmol), its concentration in blood plasma has been steadily declining, and was on the fifth day of the experiment 13.0 + 1 , 0 mmol (background — 20.0 + 1.0 mmol). The reason is, apparently, in the absence of physiological compensatory mechanisms quickly eliminate metabolic potassium. Even on the second day after the end of the experiment, the potassium content in the plasma remained at low numbers.
At the very strict regime of water saving, sooner or later there comes a moment when its reserves are coming to an end.
Severe suffering from thirst the traveler, lost in the desert, but his thousand-flour in the ocean. Man sees a sparkling water surface, hears whispering waves, feel the touch of refreshing spray — and can not quench your thirst.
True, the Chronicle of maritime disasters knows of cases where victims of shipwrecks used sea water to sustain life. Almost 70 days of ocean water quenched his thirst Poon Lim, an American sailor of the transport ship torpedoed by the Japanese during World War II. Sea water helped to survive the young navy doctor Yeresko P., 37 days in the boat in the Black Sea without fresh water.
It would seem that the arguments Bombara, Willis, and cases where the sea water used by people in poverty in the ocean, are convincing enough. But Hannes Lindemann after publication of recommendations Bombara The press made a sharp dispute:.
The experiments conducted in the laboratory of the French surgeon J. Ory in 1954, and S. Lounge in 1957, did not bring clarity to this issue. On the one hand, the changes detected in tested volunteers, drank sea water in small portions over 3 — 5 days, were minor: some increased blood levels of sodium, chloride, urea, and decreased slightly alkaline reserve of blood, and the other — the amount of allocated urine was significantly higher than the amount of water you drink.