Efekti smjenskoga rada na dinamiku srčane aktivnosti i percepciju posla

Previous studies have shown negative effects of shift work on health, due to the desynchronization and resynchronization of biological rhythms. In these studies, among other parameters, indicators of cardiac dynamics were used, such as parameters of R-R interval variability, reduction in what has been considered a good predictor of health problems by some authors. The aim of this study was to determine the possible effects of shift work on the parameters of cardiac dynamics and the job perceptions of nurses of different lengths of service. The study included 48 nurses divided in two groups (24 nurses in each) of equal age and length of service. One group worked a three-shift rotation system and the other (control) worked only the day shift. On the basis of length of service, the groups were divided into three comparable subgroups with eight participants: 1–10, 11–20 and 21–30 years of service. Cardiac activity (R-R intervals) was monitored continuously during the morning shift using the Data Logging System. The participants also evaluated their satisfaction with the job, the difficulty of the work, and the impact of working hours on other aspects of life. Analysis of the results showed reduced variability in cardiac activity (DM-index) in the shift workers with up to 20 years of service, as compared with the comparative groups of day workers, which indicates a less favourable health dynamic. Differences among the oldest groups were not found, which can be attributed to spontaneous selection, where shift workers with health problems are transferred to the day shift. The shift workers were less satisfied with their job, assessing it as more difficult than the daytime workers, and showed a greater level of negative impact of working hours on other domains of life. Despite the specific and limited sample, resulting from difficulties in collecting the psychophysiological variables, the results show a satisfactory reliability and point to an adverse job perception and a cardiac dynamic less favourable for health.Dosadašnja istraživanja su pokazala negativne efekte smjenskog rada na zdravlje u čijoj se osnovi dominantno nalazi desinkronizacija i resinkronizacija bioloških ritmova. U ovakvim istraživanjima korišteni su, između ostalih, i indikatori promjena dinamike srčane aktivnosti, kao što su parametri varijabiliteta R-R intervala, čije atipično smanjenje neki autori smatraju dobrim prediktorom zdravstvenih problema. Cilj istraživanja bio je utvrditi eventualne efekte smjenskog rada na parametre srčane dinamike te percepciju posla medicinskih sestara različite dužine radnog staža. U ispitivanju su sudjelovale dvije skupine od po 24 medicinske sestre, izjednačene po dobi i duljini radnog staža. Jedna je skupina radila u trosmjenskom sustavu rotacije smjena, a druga (kontrolna) samo u dnevnoj smjeni. Na osnovi dužine radnog staža, skupine su podijeljene u tri komparabilne podskupine s po osam sudionica, i to s: 1-10, 11-20 i 21-30 godina radnog staža. Srčana aktivnost (R-R intervali) kontinuirano je registrirana za vrijeme jutarnje radne smjene pomoću Data Logging sustava. Sudionice su također procjenjivale zadovoljstvo i težinu posla, te utjecaj radnog vremena na ostale segmente života. Kod smjenskih radnica koje su imale do 20 godina staža utvrđen je smanjen varijabilitet srčane aktivnosti (DM-indeks) u odnosu na komparabilne grupe dnevnih radnica, što može biti indikator povećanog rizika od oboljenja. Razlike među najstarijim skupinama nisu nađene, što se može pripisati spontanoj selekciji gdje su smjenske radnice sa zdravstvenim problemima premještane u dnevnu smjenu. Smjenske radnice su bile manje zadovoljne svojim poslom, procjenjivale su ga težim nego dnevne radnice, te su iskazale veću razinu negativnog utjecaja posla na ostale domene života. Iako je zbog zahtjevnosti prikupljanja psihofizioloških varijabli uzorak u istraživanju specifičan i malen, rezultati pokazuju zadovoljavajuću pouzdanost i upućuju na nižu razinu dobrobiti smjenskih u odnosu na dnevne radnice

Efeitos do trabalho em turnos na saúde do trabalhador: revisão sistemática

Este estudo visa, por meio de uma revisão sistemática da literatura, descrever o efeito do trabalho em turnos na saúde do trabalhador. Foram utilizados os descritores “risco ocupacional”, “saúde ocupacional” e “trabalho em turnos” para publicações entre 2000 e 2007, disponíveison-line. Foram selecionadas publicações das bases Medical Literature Analysis and Retrieval System Online (MEDLINE) – associou-se Trabalho em Turnos e Risco Ocupacional e o primeiro com Saúde Ocupacional – e Scientific Eletronic Library Online (SciELO) – descritores foram usados isoladamente. Dos 117 artigos capturados, 37 foram incluídos, sendo 91,7% em inglês, 70,3% estudos transversais, 18,9% corte e 10,8% caso controle. As investigações abordam alterações cardiovasculares (24,4%), qualidade do sono e estado de alerta (17,7%), alterações metabólicas (13,3%), entre outros. Algumas pesquisas não associaram alterações da saúde dos trabalhadores ao trabalho em turno

Assessment of Cardiac Autonomic Function in Relation to Methylmercury Neurotoxicity

After the European Food Safety Authority reviewed reports of methylmercury and heart rate variability (HRV) in 2012, the panel concluded that, although some studies of cardiac autonomy suggested an autonomic effect of methylmercury, the results were inconsistent among studies and the implications for health were unclear. In this study, we reconsider this association by adding a perspective on the physiological context. Cardiovascular rhythmicity is usually studied within different frequency domains of HRV. Three spectral components are usually detected; in humans these are centered at <0.04 Hz, 0.15 Hz (LF), and 0.3 Hz (HF). LF and HF (sympathetic and parasympathetic activities, respectively) are evaluated in terms of frequency and power. By searching PubMed, we identified 13 studies examining the effect of methylmercury exposure on HRV in human populations in the Faroe Islands, the Seychelles and other countries. Considering both reduced HRV and sympathodominant state (i.e., lower HF, higher LF, or higher LF/HF ratio) as autonomic abnormality, eight of them showed the significant association with methylmercury exposure. Five studies failed to demonstrate any significant association. In conclusion, these data suggest that increased methylmercury exposure was consistently associated with autonomic abnormality, though the influence of methylmercury on HRV (e.g., LF) might differ for prenatal and postnatal exposures. The results with HRV should be included in the risk characterization of methylmercury. The HRV parameters calculated by frequency domain analysis appear to be more sensitive to methylmercury exposure than those by time domain analysis

Mercury and Methylmercury Toxicology and Risk Assessment

Mercury is a global pollutant that affects the health of both humans and ecosystems. This Special Issue collects three review papers and six research articles that report on the latest findings on the mechanisms of mercury toxicology and its impacts on environmental health. This collection of papers provides useful, new information on the mechanisms of mercury toxicity and methods of improving the risk assessment of mercury exposure

Autonomic function in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory condition with poorly understood pathophysiology and increased cardiovascular risk. The mechanisms for increased cardiovascular risk are not fully known, however one novel mechanism explored in this thesis is autonomic nervous system (ANS) dysfunction. The thesis comprises of: a systematic literature review; two case-control studies (n=30 RA patients, n=34 controls; a longitudinal case-study (n=1 RA patient); a cohort study (n=112 RA patients); and a randomised placebo controlled crossover study (n=10 healthy controls). The work presented in this thesis demonstrates that ANS dysfunction is prevalent in ~60 % of RA patients and characterised by heightened sympathetic outflow to the peripheral vasculature (determined by muscle sympathetic nerve activity using microneurography), depressed baroreflex control of heart rate (determined using the modified Oxford technique), depressed heart rate variability and heightened vascular responses to stressors (cold pressor test and mental stress). Inflammation was associated with ANS dysfunction, and may well contribute to the increased cardiovascular risk seen in RA. Further studies are required to: confirm these findings; determine whether therapeutic strategies to restore ANS function improve prognosis in RA; and further explore the precise mechanisms by which inflammatory cytokines may influence ANS function in health and disease