Circadian rhythm is a cycle of biochemical, physiological or behavioural processes of approx. 24 hours, belonging to living entities, including plants, animals. Many studies showed the removal from any measurement source, internal time seems to operate for a long day of approx. 25 hours. When biological is desynchronized to that of the society, dysfunctionalities start appearing at physical, mental and behavioural level which shall influence sleep, hormone secretions, body temperature etc. The desynchronizations arisen due to the disorder of rhythm may be an aggravating factor for the appearance of chronic diseases, from high blood pressure, to diabetes mellitus, depression and even cancer. Circadian rhythm is involved in days related temporization but it also is an element in the body physiological and behavioural adaptation, to passing to a new season. Recent measurements performed by Harvard professors showed that such rhythm has 24 hours and 11 minutes, the internal duration of a day being the same for the young, and for the elderly. Many of the functions of the body have a rhythm, from sleep-awake cycle, to the vital signs of the body. As science becomes more and more exact in its measurements, more and more rhythms are recognized; therefore, they recently discovered that bones growth takes place according to rhythm. The human body represents a miraculous universal biological oscillator, subordinated to endogenous stimuli (genetic signals of pace-makers) and environmental factors (zeitgerber - synchronizers), biorhythms depend upon. Bioperiodicity is a fundamental property of the living matter. The common element of course is represented by biological rhythms, as all biological functions develop with time. The period of a biological rhythm is well profiled, which reflects the individual, hereditary character, and therefore, transmissible to following generations. The human being is born as such, not only with spatial biological structure, but also temporal. Physiologically speaking, recent studies showed that rhythm consists of a set of interconnected proteins which have the capacity to generate their own rhythm. Cell physiology is object of an internal watch with the length of 24 hours, which consists of interconnected molecular loops. This human biological clock is genetically printed, there existing in our brains a type of heart stimulator placed inside the suprachiasmatic nuclei being deeply influenced by factors like light, temperature of the surrounding environment, sleep, social contact, physical activity, and even regular table intervals. Neurotransmitters, neuromodulators and neuropeptides are those controlling the operation of the circadian watch. Neurobiology of (chronobiology), with biological infradian SCIENTIFIC RESEARCH AND EDUCATION IN THE AIR FORCE-AFASES 2016