Background: Living at high altitude or with chronic hypoxia implies functional and morphological changes in the right ventricle and pulmonary vasculature with a 10% prevalence of high-altitude pulmonary hypertension (HAPH). The implications of working intermittently (day shifts) at high altitude (hypobaric hypoxia) over the long term are still not well-defined. The aim of this study was to evaluate the right cardiac circuit status along with potentially contributory metabolic variables and distinctive responses after long exposure to the latter condition.Methods: A cross-sectional study of 120 healthy miners working at an altitude of 4,400–4,800 m for over 5 years in 7-day commuting shifts was designed. Echocardiography was performed on day 2 at sea level. Additionally, biomedical and biochemical variables, Lake Louise scores (LLSs), sleep disturbances and physiological variables were measured at altitude and at sea level.Results: The population was 41.8 ± 0.7 years old, with an average of 14 ± 0.5 (range 5–29) years spent at altitude. Most subjects still suffered from mild to moderate symptoms of acute mountain sickness (mild was an LLS of 3–5 points, including cephalea; moderate was LLS of 6–10 points) (38.3%) at the end of day 1 of the shift. Echocardiography showed a 23% mean pulmonary artery pressure (mPAP) >25 mmHg, 9% HAPH (≥30 mmHg), 85% mild increase in right ventricle wall thickness (≥5 mm), 64% mild right ventricle dilation, low pulmonary vascular resistance (PVR) and fairly good ventricle performance. Asymmetric dimethylarginine (ADMA) (OR 8.84 (1.18–66.39); p < 0.05) and insulin (OR: 1.11 (1.02–1.20); p < 0.05) were associated with elevated mPAP and were defined as a cut-off. Interestingly, the correspondence analysis identified association patterns of several other variables (metabolic, labor, and biomedical) with higher mPAP.Conclusions: Working intermittently at high altitude involves a distinctive pattern. The most relevant and novel characteristics are a greater prevalence of elevated mPAP and HAPH than previously reported at chronic intermittent hypobaric hypoxia (CIHH), which is accompanied by subsequent morphological characteristics. These findings are associated with cardiometabolic factors (insulin and ADMA). However, the functional repercussions seem to be minor or negligible. This research contributes to our understanding and surveillance of this unique model of chronic intermittent high-altitude exposure.

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In southern European cities, research on deprivation and mortality inequalities using small-area analysis is recent. In many countries, the census tract (CT) is

Oxygen challenge imaging involves transient hyperoxia applied during deoxyhaemoglobin sensitive (T2*-weighted) magnetic resonance imaging and has the potential to detect changes in brain oxygen extraction. In order to develop optimal practical protocols for oxygen challenge imaging, we investigated the influence of oxygen concentration, cerebral blood flow change, pattern of oxygen administration and field strength on T2*-weighted signal. Eight healthy volunteers underwent multi-parametric magnetic resonance imaging including oxygen challenge imaging and arterial spin labelling using two oxygen concentrations (target FiO 2 of 100 and 60%) administered consecutively (two-stage challenge) at both 1.5T and 3T. There was a greater signal increase in grey matter compared to white matter during oxygen challenge (p < 0.002 at 3T, P < 0.0001 at 1.5T) and at FiO 2 ¼ 100% compared to FiO 2 ¼ 60% in grey matter at both field strengths (p < 0.02) and in white matter at 3Tonly (p ¼ 0.0314). Differences in the magnitude of signal change between 1.5T and 3T did not reach statistical significance. Reduction of T2*-weighted signal to below baseline, after hyperoxia withdrawal, confounded interpretation of two-stage oxygen challenge imaging. Reductions in cerebral blood flow did not obscure the T2*-weighted signal increases. In conclusion, the optimal protocol for further study should utilise target FiO 2 ¼ 100% during a single oxygen challenge. Imaging at both 1.5T and 3T is clinically feasible.