Hydrogen element and hydrogen gas

Abstract

Features of hydrogen, discovery history of hydrogen, and physical and chemical properties, especially those correlated with the biological effects of hydrogen, are important for the understanding of mechanisms underlying the biological effects of hydrogen. In this chapter, we introduce the formulation, discovery, and physical and chemical properties of hydrogen. Most substances in the universe are composed of hydrogen element. Even human beings, the most complex form of life on Earth, are composed of hydrogen element. However, few studies have been conducted to focus on the biological effects of hydrogen before the magically biological effects of hydrogen are revealed by scientists in recent years. A secret may still be hidden in these wonder effects of hydrogen. Though hydrogen has a considerable low solubility in water, its concentration can still approach 0.9 mmol/L. Hydrogen, at this concentration, has been found to be able to confer its protective effects in biological system. Hydrogen is a gas molecule with relatively constant reducibility, an important chemical property of hydrogen. It has been accepted that hydrogen cannot directly interact with substances in biological body and that is why we use hydrogen in diving. However, recent studies reveal that hydrogen is able to neutralize some free radicals conferring protective effects, which maybe a chemical mechanism underlying the biological effects of hydrogen.