40 research outputs found

    Neuromuscular Consequences of an Extreme Mountain Ultra-Marathon

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    We investigated the physiological consequences of one of the most extreme exercises realized by humans in race conditions: a 166-km mountain ultra-marathon (MUM) with 9500 m of positive and negative elevation change. For this purpose, (i) the fatigue induced by the MUM and (ii) the recovery processes over two weeks were assessed. Evaluation of neuromuscular function (NMF) and blood markers of muscle damage and inflammation were performed before and immediately following (n = 22), and 2, 5, 9 and 16 days after the MUM (n = 11) in experienced ultra-marathon runners. Large maximal voluntary contraction decreases occurred after MUM (−35% [95% CI: −28 to −42%] and −39% [95% CI: −32 to −46%] for KE and PF, respectively), with alteration of maximal voluntary activation, mainly for KE (−19% [95% CI: −7 to −32%]). Significant modifications in markers of muscle damage and inflammation were observed after the MUM as suggested by the large changes in creatine kinase (from 144±94 to 13,633±12,626 UI L−1), myoglobin (from 32±22 to 1,432±1,209 µg L−1), and C-Reactive Protein (from <2.0 to 37.7±26.5 mg L−1). Moderate to large reductions in maximal compound muscle action potential amplitude, high-frequency doublet force, and low frequency fatigue (index of excitation-contraction coupling alteration) were also observed for both muscle groups. Sixteen days after MUM, NMF had returned to initial values, with most of the recovery process occurring within 9 days of the race. These findings suggest that the large alterations in NMF after an ultra-marathon race are multi-factorial, including failure of excitation-contraction coupling, which has never been described after prolonged running. It is also concluded that as early as two weeks after such an extreme running exercise, maximal force capacities have returned to baseline

    Impact of a mountain ultra-marathon (UTMB) on cardiac biomarkers

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    OBJECTIVES: While moderate exercise has beneficial effects on the cardiovascular system, consequences of a supraphysiological effort are not clear yet. In particular, the physiological consequences of ultramarathons need to be further documented. The aim of the study was to assess the changes of various cardiac biomarkers after a mountain ultramarathon. MATERIAL AND METHODS: Blood and urine samples were collected on 28 runners (17 men) participating to the UltraTrail du Mont Blanc (105 km, total positive elevation: 5600 m) at 3 different times: before the race (Pre), within 1 h after the finish (Post) and 7 days after the finish (D+7). Several biomarkers involved in heart disease (coronary syndrome, heart failure and fibrosis) and in inflammation were assayed on different analyzers such a COBAS® (for CKMB,TnThs, NTproBNP, HFABP and CRPs) and KRYPTOR® (for Copeptin). ST2 was measured manually with the Presage kit from CRITICAL DIAGNOSTIC®. RESULTS: Plasma levels of cardiac markers (CKMB, TnThs, NTproBNP, copeptin, HFABP, ST2) and inflammation (CRPs) increased significantly at Post. Means values increased from Pre to Post as follows: 2.3 to 91.9 UI/L for CKMB (p<0.0001); 7.6 to 31.7 ng/L for TnThs (p<0.0001); 41.7 to 1190.5 ng/L for NTproBNP, 4.2 to 22.9 pmol/L for copeptin (p=0.001); 3.6 to 107.8 ng/mL for HFABP (p<0.0001), 29.7 to 126.2 ng/mL for ST2 (p<0.0001); 0.5 to 29.1 mg/L for CRPs (p<0.0001). With the exception of a few (HFABP, ST2, CRPs) biomarkers in some subjects, all values were back to Pre values at D+7. DISCUSSION/CONCLUSION: Prolonged strenuous running exercise caused an elevation in cardiac biomarkers. Elevation in CKMB levels lacks specificity for cardiac damage as runners have increased CKMB from skeletal muscles as well. Previous studies suggested that exercise induced TnThs elevation is a benign reversible physiologic phenomenon but this parameter, as well as HFABP, could be a sign of ischemia. Different phenomena occurred such as stretch of myocytes causing an increase in pressure or volume and neurohormonal activation which can explain the Copeptine and NTproBNP increase, while ST2 is a biomarker of cardiac remodeling and fibrosis. CRP is an acute phase compound that tends to increase following a strenuous and prolonged bout of exercise and/or muscular injury. As the values tended to return within the normal reference range values within 7 days after the race, our study suggests that there is no permanent structural damage at the myocardium level

    A Deep Learning-Based Automated Framework for Subpeak Designation on Intracranial Pressure Signals

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    International audienceThe intracranial pressure (ICP) signal, as monitored on patients inintensive care units, contains pulses of cardiac origin, where P1and P2 subpeaks can often be observed. When calculable, the ratioof their relative amplitudes is an indicator of the patient’scerebral compliance. This characterization is particularlyinformative for the overall state of the cerebrospinal system. Theaim of this study is to develop and assess the performances of adeep learning-based pipeline for P2/P1 ratio computation that onlytakes a raw ICP signal as an input. The output P2/P1 ratio signalcan be discontinuous since P1 and P2 subpeaks are not alwaysvisible. The proposed pipeline performs four tasks, namely (i)heartbeat-induced pulse detection, (ii) pulse selection, (iii) P1and P2 designation, and (iv) signal smoothing and outlier removal.For tasks (i) and (ii), the performance of a recurrent neuralnetwork is compared to that of a convolutional neural network. Thefinal algorithm is evaluated on a 4344-pulse testing datasetsampled from 10 patient recordings. Pulse selection is achievedwith an area under the curve of 0.90, whereas the subpeakdesignation algorithm identifies pulses with a P2/P1 ratio &gt; 1with 97.3% accuracy. Although it still needs to be evaluated on alarger number of labeled recordings, our automated P2/P1 ratiocalculation framework appears to be a promising tool that can beeasily embedded into bedside monitoring devices

    Prevalence of self-reported fatigue in intensive care unit survivors 6 months–5 years after discharge

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    International audienceAbstract Prolonged stays in intensive care units (ICU) are responsible for long-lasting consequences, fatigue being one of the more debilitating. Yet, fatigue prevalence for patients that have experienced ICU stays remains poorly investigated. This study aimed to evaluate fatigue prevalence and the level of physical activity in ICU survivors from 6 months to 5 years after ICU discharge using the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) and Godin questionnaires, respectively. Data from 351 ICU survivors (out of 1583 contacted) showed that 199 (57%) and 152 (43%) were considered as fatigued and non-fatigued, respectively. The median FACIT-F scores for fatigued versus non-fatigued ICU survivors were 21 (14–27) and 45 (41–48), respectively (p < 0.001). Time from discharge had no significant effect on fatigue prevalence (p = 0.30) and fatigued ICU survivors are less active (p < 0.001). In multivariate analysis, the only risk factor of being fatigued that was identified was being female. We reported a high prevalence of fatigue among ICU survivors. Sex was the only independent risk factor of being fatigued, with females being more prone to this symptom. Further studies should consider experimental approaches that help us understand the objective causes of fatigue, and to build targeted fatigue management interventions

    Mountain Ultra-Marathon (UTMB) Impact on Usual and Emerging Cardiac Biomarkers

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    The number of participants in ultra-marathons is increasing. However, the data regarding the impact of this type of exercise on the cardiovascular system are contradictory. In our study, 28 ultra-trail runners were enrolled. Blood samples were collected at three time points: immediately before, immediately after, and 7 days after the ultra-marathon. Different biomarkers were measured. Immediately after the race, the blood concentrations of the different cardiac and inflammatory biomarkers increased significantly. Interestingly, some biomarkers remained high even after 7 days of recovery
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