The Dead Sea, a unique natural health resort.

The Dead Sea area is unique for its combination of natural resources that are unparalleled anywhere else on earth. They include sun rays that are weakened due to the longer path they have to travel to reach the Dead Sea shores, which are 415 m below sea level, and the dispersion of the sun rays on their way by a misty cloud overhanging the sea most of the year. The attenuation is in inverse relation to the length of the ray; as a result, the shorter ultraviolet B rays are attenuated to greater extent than the longer UVA rays (12% and 3.8% on average respectively). This difference in solar radiation intensity provides a major therapeutic advantage, since damage to the skin after solar exposure increases as the UVB solar rays become shorter. However, the effective wavelength for suppressing psoriatic skin lesions is around 311 nm, a range at the longer wavelength end of the UVB scale [1,2]. In addition to the unique composition of sun rays, the low altitude of the area results in a high atmospheric pressure (37 mmHg), which is approximately 5% higher than at sea level. As a result the partial oxygen tension at the Dead Sea is about 7–8 mmHg higher than at zero altitude; this has important therapeutic implications for patients with hypoxic heart and lung diseases, as will be specified below. The water in this lake, as compared to seawater, contains an unusual composition and unusually high concentrations of cations, e.g., magnesium, sodium, calcium, and anions such as phosphorus, bromide and chloride. These raise the density of the water to about 1.237 kg/L, causing people bathing in the lake to float on rather than swim in the water. Certain minerals in the water have been shown to penetrate the skin, which may contribute to its healing effect [3]. Nanotechnological techniques are presently being explored to improve the penetration of therapeutic agents through the skin. Mineral and sulphur-containing natural springs are found along the shores. Also, black mud, which contains medicinal antibacte-rial and hyperemic properties [4], is extracted from the shores of the lake. With regard to climate, a dry stable temperature reaches high levels during midsummer, while an extremely low rainfall is recorded in the very moderate winter. The elevated barometric pressure, high temperature and low humidity have been shown to have a favorable effect on patients with various rheumatic diseases. The air, which …