Variabilidade da frequencia cardiaca em trabalhadores em turnos / Heart rate variability in shift workers

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

In industrialized countries approximately 15 to 20% of the workforce is engaged on shift work and this is associated with an increased rate of cardiovascular diseases. It is still not clear but the alterations in circadian rhythms of the cardiac autonomic nervous system could explain this phenomenon. A non-invasive tool to evaluate autonomic nervous system activity is the emporal and spectral analysis of heart rate variability (HRV) calculated through a 24-hour electrocardiography monitoring. The objective of this study was to analyze the heart rate variations of 32 healthy nurses (ages ranging from 35, 62 ± 6, 17) engaged on fixed shift work for a university hospital. The volunteers were divided in three groups according to their working hours: morning (from 7 a.m. to 1 p.m), evening (from 1 p.m to 7 p.m.) and night (from 7 p.m. to 7 a.m.), and also submitted to clinical, physiotherapic and functional cardiorespiratory evaluations. Data relating to exposure time, personal habits (physical activity and etilism), istory of parental illnesses and monthly cycles were obtained. Additionally, a clinical examination was performed including analysis of vital signs at rest (heart and breath rate and blood pressure) and lipid profile blood tests. During the physical evaluation, anthropometric variations were measured such as weight, height, body mass index (BMI), waistto- hip ratio (WHR) and fat mass percentage. The functional cardiorespiratory evaluation included maximum ergometric and 24-h electrocardiography tests which were applied to the groups as follows: day shift-workers (morning and noon) were monitored over a period of one working day whereas the nigh shift-workers were monitored over the full working day plus the whole off-work day. Our HRV results showed physiological behaviour of sympathetic and vagal components with no significant statistical differences. However, night-shift volunteers presented older age, longer exposure time, higher weight, BMI, WHR and fat mass percentage, factors which could interfere with the HRV and ergometric test results. Therefore, we observed that the results obtained for night shift-workers, comparing work and off-work days, suggest that there are alterations in cardiac autonomic control

ASSUNTO(S)

cardiovascular disease batimento cardiaco heart rate shift work trabalhos em turno doenças cardiovasculares

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