Hygiena 2014, 59(1):32-36 | DOI: 10.21101/hygiena.a1193

Circadian Disruptors and Their Importance in Primary Prevention

Drahoslava Hrubá

Masarykova univerzita, Lékařská fakulta, Ústav preventivního lékařství, Brno

All vertebrates, including humans, have a biological circadian clock. Their receptors are located on the retina, and information regarding the alternation of day and night are transferred to a centre in the hypothalamus and from there into the pineal gland which produces melatonin (N-acetyl-5-metoxytryptamin), almost exclusively during the hours of darkness. The hormone is quickly discharged into the bloodstream and cerebrospinal fluid into all cells. Such immediate information about the circadian phase of day/night changes allows to organs and organism to regulate their physiological functions. Current research suggests that melatonin is involved in several important physiological functions: sleep regulation and circadian rhythms, mood, immunity, oncostatic and antioxidant activities. Synthesis of melatonin reduces with age. Artificial light in the evenings and early mornings reduces the dark part of the day and even brief use of artificial light at night reduces the levels of melatonin produced over a 24-hour period. Air transport over a number of time-zones likewise significantly disrupts melatonin production. The health consequences of the disruption of biologcal rhythms include sleep disorders, higher frequency of some types of cancer, obesity, metabolic syndrome, diabetes and aggravation of some neurodegenerative symptoms. In primary prevention it is necessary to limit the duration of night shifts and educate the public on the importance of night sleep.

Keywords: circadian rhythms, endocrine disruptors (ECD), melatonin, disease prevention

Received: October 2012; Accepted: January 21, 2013; Published: March 1, 2014  Show citation