Getting the right amount of restful sleep<\/strong> every night is essential when it comes to enjoying an optimal state of health and well-being. To this end, it is important to know that the sleep-wakefulness cycle<\/strong> is regulated by the circadian rhythm, that is, by the biological changes that occur over a 24-hour cycle. As Vicente Mera, specialist in Sleep Medicine at SHA, explains, \u201cthe circadian rhythm is the oldest element of life shared by all living beings on the planet. Millions of years ago, primitive molecules<\/strong> began to join together in more complex organisms and, to protect themselves from ultraviolet radiation, they relegated certain functions to night-time<\/strong>. Thus, they defended themselves from the sun in the morning and regenerated at night. It is this same process that causes the body\u2019s production of melatonin, the hormone that regulates our biological clock<\/strong>, to increase after dark and cease during the day\u201d.<\/p>\n