[State of vegetative nervous system in workers engaged into multiple shifts work with night shifts].

Occupational activity with night shifts and length of service over 5 years is characterized by prevalent sympathetic influence on cardiac activity, vagosympathetic interaction index (LF/HF) is considerably higher than in workers with lower length of service and 1.5 times exceeding upper normal value. VLF indicator exceeds physiologic normal value due to increased activity of ergotropic and humoral metabolic mechanisms of cardiac rhythm regulation. Sympathetic regulation activity level (LF parameter) is also reliably higher than in workers with lower length of service (p = 0.024). Parasympathetic regulation activity level (HF parameter) is below normal value - that indicates decreased influence of parasympathetic vegetative system on cardiac activity (depression of defence mechanisms). Comparative analysis of vegetative regulation spectrum at rest, in accordance with length of service, demonstrated the most marked changes in workers with length of service over 5 years: lower total spectral capacity (TP, msz), lower share of high-frequency waves (HF, %), increase of average vagosympathetic interaction index (LF/HF) and higher share of very low waves (VLF, %) in the spectrum structure. Ihe data prove intensified ergotropic, humoral, sympathetic influences on cardiac activity and, as a result, higher risk of dysmetabolic processes and cardiovascular diseases.