[Assessment of heart rate variability (HRV) as a stress index in an emergency team of urban police]. / Valutazione della variabilità della frequenza cardiaca (HRV) come indice di stress in addetti al pronto intervento nella polizia urbana.

ABSTRACT

Stress is usually defined as the experience of negative events or the perceptions of distress and negative affect that are associated with the inability to cope with them. The parameter most suitable for large-scale field studies is the determination of endocrine activity by measurement of salivary cortisol. The aim of the present study is to identify the presence of sources of stress in an emergency team of urban police and to objective such stress using the PSS (Professional Stress Scale) test and bioumoral markers as salivary cortisol and interleukin 1 beta (IL1-B). Moreover it will be determined the Heart Rate Variability (HRV) that is able to mirror the sympathetic-parasympathetic balance. We studied 30 policemen who belonged to an emergency team. Thirty policemen made cardiologic exams as ECG, Heart Eco-doppler and Holter Ecg during the work and during the holiday. Particularly we studied HRV using frequency-domain based HRV measures. The results were evidenced as the differences of the spectral power. As control we used the same subjects during the holiday. T test was performed to evaluate the differences between the means, the Chi Square's Test was performed to determine the statistically significant association between PSS subscales, HRV, salivary cortisol and IL1-B concentrations. The study of HRV demonstrated a statistically significant association between HRV parameters during the holiday, salivary cortisol concentrations and PSS test. IL1-B, instead, was not associated with HRV parameters. Several precedent studies agree with our results. Our study has suggested a work related stress in urban police employed in an emergency team. We might conclude that salivary IL1-B and cortisol are useful markers of stress. The study of HRV parameters gave evidence that LF/HF during the holiday is a useful marker of work stress, because it correlated with cortisol difference during the work. Conclusively we can believe that the HRV parameters evaluated during the work are useful as confront, instead the HRV parameters during the holiday are surest indexes of work stress. Probably the effect of stress on the heart aren't present during the work because the work experience reduces these effects, they appear during the holiday when the imagination could make the conflicts or the problems more complex than they are. It might be useful to repeat this study after some structure organizational modifications and after training that will teach the workers coping strategies. If we consider only the bioumoral and PSS results, we might conclude that the stress discovered in this study is not hazardous for the health when the workers have adequate holidays, but if we evaluate the HRV parameters, we have believe that, for a heart health, it's necessary either to increment the holidays or, it can appear paradoxical, to work again.