Samuel Verges

Grenoble Alpes University, INSERM (French Institute of Health and Medical Research) · Hypoxia Physiopathology Laboratory (HP2)

Background. Low daily physical activity and poor exercise tolerance are cardinal features in fibrotic interstitial lung disease (f-ILD) (1, 2). Besides, cerebral hypoxia may exacerbate the perception of fatigue during exercise.(3) We previously showed that activity-related hypoxaemia, another hallmark of f-ILD, dose-dependently impairs cerebral oxy...

Both respiratory muscle endurance training (RMET) and inspiratory resistive training (IMT) seem to increase whole-body exercise performance, but direct comparisons between the two are scarce. We hypothesized that the similarity of RMET to exercise-induced ventilation would induce larger improvements compared to IMT. Twenty-six moderately-trained me...

To develop a simplified magnetic resonance imaging method (MRI) to assess total adipose tissue (AT) and adipose tissue free mass (ATFM) from three single MRI slices in people with overweight/obesity in order to implement body composition follow-up in a clinical research setting. Body composition of 310 participants (70 women and 240 men, age: 50.8...

Purpose: We aimed to investigate respiratory rate variability (RRV) and tidal volume (Vt) variability during exposure to normobaric hypoxia (i.e., reduction in the fraction of inspired oxygen - FiO2), and the association of the changes in RRV and Vt variability with the changes in pulse oxygen saturation (SpO2). Methods: Thirty healthy human par...

Permanent residence at high-altitude and chronic mountain sickness (CMS) may alter the cerebrovascular homeostasis and orthostatic responses. 15/13/17 healthy participants living at sea-level (LL), 3,800m (HL3800m) and 5,100m (HL5100m), respectively, and 31 additional highlanders with CMS living at 5,100m were recruited. Middle cerebral artery mean...

Purpose: Cerebral hypoxia may exacerbate the perception of fatigue. We previously demonstrated that exercise-related hypoxemia, a hallmark of fibrotic interstitial lung disease (f-ILD), dose-dependently impairs cerebral oxygenation in these patients. It is unknown whether normalizing cerebral oxygenation with O2 supplementation would be associated...

Introduction and Objectives: Chronic Mountain Sickness (CMS) syndrome, combining excessive erythrocytosis and clinical symptoms in highlanders, remains a public health concern in high-altitude areas, especially in the Andes, with limited therapeutic approaches. The objectives of this study were to assess in CMS-highlanders permanently living in La...

This study suggests that interventions geared to improve peripheral factors of performance fatigability during exercise in interstitial lung disease may prove valuable to decrease patients' perceived fatigability, since both seem closely related https://bit.ly/3lpIUPs.

Investigation of pulmonary gas exchange efficacy usually requires arterial blood gas analysis (aBGA) to determine arterial partial pressure of oxygen (mPaO2) and compute the Riley alveolar-to-arterial oxygen difference (A-aDO2); that is a demanding and invasive procedure. A noninvasive approach (AGM100), allowing the calculation of PaO2 (cPaO2) der...

Introduction Chronic mountain sickness (CMS) is a condition characterized by excessive erythrocytosis in response to chronic hypobaric hypoxia. CMS frequently triggers cardiorespiratory diseases such as pulmonary hypertension and right or left heart failure. Ambient hypoxia might be further amplified night-time by intermittent hypoxia related to sl...

Background: Hypoxemia and cardiocirculatory abnormalities may impair muscle oxygen (O2) delivery relative to O2 requirements thereby increasing the rate of O2 extraction during incremental exercise in fibrotic interstitial lung disease (f-ILD). Using changes in deoxyhemoglobin concentration ([HHb]) by near-infrared spectroscopy (NIRS) as a proxy o...

Introduction: A lack of knowledge among laypersons about the hazards of high-altitude exposure contributes to morbidity and mortality from acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) among high-altitude travelers. There are guidelines regarding the recognition, prevention, and treatme...

Introduction: Combining moderate intensity exercise training with hypoxic exposure may induce larger improvement in cardiometabolic risk factors and health status compared to normoxic exercise training in obesity. Considering the greater cardiometabolic effects of high intensity intermittent training (HIIT), we hypothesized that hypoxic high-volum...

Objectives: The aim of the present study was to investigate the level of cardiorespiratory fitness and neuromuscular function of ICU survivors after COVID-19 and to examine whether these outcomes are related to ICU stay/mechanical ventilation duration. Design: Prospective nonrandomized study. Setting: Patients hospitalized in ICU for COVID-19...

Left/right prefrontal cortex (PFC) activation is linked to positive/negative affects, respectively. Besides, larger left PFC oxygenation during exercise relates to higher cardiorespiratory fitness (CRF). High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. The influence of training o...

Aims A unique Andean population lives in the highest city of the world (La Rinconada, 5,100 m, Peru) and frequently develops a maladaptive syndrome, termed chronic mountain sickness (CMS). Both extreme altitude and CMS are a challenge for the cardiovascular system. This study aims to evaluate cardiac remodelling and pulmonary circulation at rest an...

High altitude exposes humans to hypobaric hypoxia, which induces various physiological and molecular changes. Recent studies point toward interaction between circadian rhythms and the hypoxic response, yet their human relevance is lacking. Here, we examine the effect of different high altitudes in conjunction with time of day on human whole-blood t...

Background and objective Pulmonary rehabilitation (PR) is fundamental in the management of chronic obstructive pulmonary disease (COPD). COPD patients show a large clinical heterogeneity that may influence their response to PR. Identification of homogeneous clusters of patients who may or may not respond to PR is important to personalize patient ca...

Purpose Both prolonged exercise and acute high-altitude exposure are known to induce cardiac changes. We sought to describe the cardiac responses to speed climbing at high-altitude, including left ventricular (LV) performance assessment using the myocardial work index (MWI), a new index derived from 2D speckle tracking echocardiography (STE). Meth...

Purpose The combined effects of acute hypoxia and exercise on cognition remain to be clarified. We investigated the effect of speed climbing to high altitude on reactivity and inhibitory control in elite climbers. Methods Eleven elite climbers performed a speed ascent of the Mont-Blanc (4810 m) and were evaluated pre- (at 1000 m) and immediately p...

Background Considering the potential greater cardiocirculatory effects of high intensity interval training (HIIT), we hypothesized that a 2-month supervised a high volume short interval HIIT would induce greater improvements in CRF and cardiometabolic risk and increase long-term maintenance compared to isocaloric moderate intensity continuous train...

High-altitude exposure results in a hyperventilatory-induced respiratory alkalosis followed by renal compensation (bicarbonaturia) to return arterial blood pH(a) toward sea-level values. However, acid-base balance has not been comprehensively examined in both lowlanders and indigenous populations - where the latter are thought to be fully adapted t...

Résumé La fréquence des séjours en altitude (pour le travail, les loisirs, les voyages en avion ou en véhicule à moteur) justifie que soit posée la question de leur tolérance, en particulier chez des sujets porteurs de maladie respiratoire préexistante. La baisse de la pression barométrique, les variations de densité de l’air et les variations de t...

Introduction Les patients qui ont développé des formes graves de pneumopathie à SARS-Cov2 ont nécessité une assistance ventilatoire et une longue durée de réanimation. Une prise en charge adaptée en réhabilitation respiratoire (RR) était indiquée secondairement. L’objectif de cette étude est d’évaluer le suivi à 6 mois et d’analyser les séquelles p...

Introduction La réhabilitation respiratoire (RR) est recommandée dans la prise en charge du BPCO. L’objectif de cette étude est d’identifier des profils cliniques des patients BPCO à l’admission pour un séjour de RR selon leurs caractéristiques cliniques et leur test de marche de 6-minutes (TM6) et d’évaluer leur réponse à la RR. Méthodes Il s’agi...

Introduction Le stress est un mécanisme d’adaptation, une réaction saine mais plus ou moins intense à des situations de notre existence. Le stress post-traumatique (SPT), quant à lui, se manifeste à la suite d’un événement traumatisant. Ce syndrome est déjà documenté chez des patients réanimés intubés dont le pronostic vital a été engagé. Cette étu...

Introduction La réhabilitation respiratoire (RR) est centrale dans la prise en charge de la BPCO, mais les effets à long terme et l’intérêt d’une RR répétée ne sont pas encore clairs surtout chez les non-répondeurs à un premier séjour. L’objectif de cette étude est d’évaluer l’effet de la RR à 12 mois et l’effet de la RR répétée. Méthodes Il s’agi...

A study to measure the composition of exhaled air was carried out in subjects living in the highest city in the world: La Rinconada in Peru. People living at high altitude have a strongly disturbed metabolism and have to deal with major physiological disturbances. It is very likely that these subjects develop a disturbance of their redox system. It...

The basal metabolic rate characterizes the energy consumption of the human body at rest. It can be estimated by using respiratory gas exchange analyzers and indirect calorimetry. During cycling this value could vary due to several adaptation processes such as an increase in breathing and blood circulation, controlling body temperature, among others...

“Exercise starts and ends in the brain”: this was the title of a review article authored by Dr. Bengt Kayser back in 2003. In this piece of work, the author highlights that pioneer studies have primarily focused on the cardiorespiratory-muscle axis to set the human limits to whole-body exercise tolerance. In some circumstances, however, exercise ce...

This paper presents a set-membership observer for the estimation of carbon dioxide production during cycling. The observer uses measurements of oxygen consumption and power at pedal level together with a discrete-time linear model of gas exchange dynamics. The real process is assumed to be disturbed by unknown but bounded disturbances. The proposed...

Background and objective Pulmonary rehabilitation (PR) is essential in the management of chronic obstructive pulmonary disease (COPD), but the long-term effects and the outcomes of repeated programs especially in non-responders remain to be clarified. The aim of this study is to evaluate the long-term effect of PR 12 months after and the effect of...

Background: Pulmonary rehabilitation (PR) is fundamental in chronic obstructive pulmonary disease (COPD) management but not all patients may show functional benefits from PR. Aim: The aim of this study was to identify predictors of non-response in functional capacity to PR. Design: Observational study. Setting: Inpatient pulmonary rehabilita...

Background. Physical activity is a cornerstone for the management of obesity. Owing to, in part, lower pleasure, this population however perform very little exercise.[1] From a physiopsychological standpoint, left and right prefrontal cortex (PFC) activation are thought to be related to positive and negative affects, respectively.[2] Moreover, larg...

Purpose: Positive expiratory pressure (PEP) breathing has been shown to increase arterial oxygenation during acute hypoxic exposure but the underlying mechanisms and consequences on symptoms during prolonged high-altitude exposure remain to be elucidated. Methods: Twenty-four males (41 ± 16 years) were investigated, at sea level and at 5,085 m afte...

Champigneulle, Benoit, Ivan Hancco, Richard Renan, Stéphane Doutreleau, Emeric Stauffer, Aurélien Pichon, Julien V. Brugniaux, Hélène Péré, Pierre Bouzat, David Veyer, and Samuel Verges. High-altitude environment and COVID-19: SARS-CoV-2 seropositivity in the highest city in the world. High Alt Med Biol. 22: 000-000, 2021. Background: A reduced cor...

Background and objectives: Patients with interstitial lung disease (ILD) experience early symptoms of dyspnoea and leg fatigue during exercise together with severe and rapid oxygen desaturation. Heated and humidified nasal high flow oxygen (NHF) has been proven to enhance exercise endurance and physiological parameters in COPD patients. This study...

To determine the effect of continuous positive airway pressure (CPAP), the gold standard treatment for obstructive sleep apnea syndrome (OSAS), on gait control in severe OSAS patients. We conducted a randomized, double-blind, parallel-group, sham-controlled monocentric study in Grenoble Alpes University Hospital, France. Gait parameters were record...

Rationale Hemorheological alterations are reported in obstructive sleep apnea (OSA) and reversed with continuous positive airway pressure (CPAP), observations potentially explained by intermittent hypoxia (IH)-induced oxidative stress. Objective To investigate whether IH causes hemorheological alterations via oxidative stress. Methods Wistar rats...

Background Exercise-induced hypoxaemia is a hallmark of chronic fibrotic interstitial lung disease ( f -ILD). It remains unclear whether patients’ severe hypoxaemia may exaggerate locomotor muscle fatigue and, if so, to what extent oxygen (O 2 ) supplementation can ameliorate these abnormalities. Methods Fifteen patients (12 males, 9 with idiopath...

Introduction Some COVID-19 patients develop respiratory failure requiring admission to intensive care unit (ICU). We aim to evaluate the effects of pulmonary rehabilitation (PR) post-ICU in COVID-19 patients. Methods Twenty-one COVID-19 patients were evaluated pre- and post-PR and compared retrospectively to a non-COVID-19 group of 21 patients reh...

Significance: Oxygenation is one of the skin tissue physiological properties to follow for patient care management. Furthermore, long-term monitoring of such parameters is needed at the patient bed as well as outside the hospital. Diffuse reflectance spectroscopy has been widely used for this purpose. Aim: The aim of the study is to propose a lo...

Because of the enduring rise in the prevalence of obesity worldwide, there is continued interest in hypoxia as a mechanism underlying the pathophysiology of obesity and its comorbidities and as a potential therapeutic adjunct for the management of the disease. Lifelong exposure to altitude is accompanied by a lower risk for obesity, whereas altitud...

Purpose: A decision tree based on a clinico-physiological score (SHAI score) has been developed to detect subjects susceptible to Severe High Altitude Illness (SHAI). We aimed to validate this decision tree, to rationalize the prescription of acetazolamide (ACZ) and to specify the rule for a progressive acclimatization. Methods: Data were obtain...

It is unknown whether hypoxemia, a hallmark of fibrotic interstitial lung disease (f-ILD), may impair cerebral oxygenation during exercise in these patients. Twenty-seven patients [23 males, 72 ± 8 years, lung diffusing capacity for carbon monoxide (DLCO) = 44 ± 11% predicted] and 12 controls performed an incremental bicycle test. Prefrontal oxygen...

Introduction: Exercise limitation in chronic obstructive pulmonary disease (COPD) is multi-factorial; however, growing evidence indicates that muscle dysfunction may contribute in some patients. Areas covered: This work outlines current evidence for and against increased peripheral muscle fatigability in COPD through a comprehensive review of re...

We evaluated the respiratory workload according to the diaphragm thickening fraction (TF) during sweep gas flow (SGF) decrease during weaning from veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Design Prospective observational study Setting Monocentric Participants Patients were included if they were suitable for a first VA-ECMO weani...

Introduction Living in high altitude is challenging for the cardiovascular system, and some of highlanders develop a chronic mountain sickness (CMS). Only few data are available above the altitude of 4380 m. La Rinconada is the highest mining city in the world at an altitude of 5100 m. Objective To describe heart remodeling and pulmonary hemodynam...

Introduction Respiratory mechanic is challenging for patients treated with veno-arterial Extracorporeal Membrane Oxygenation (VA ECMO). Whereas growing evidences were reported of changes in diaphragm thickness during mechanical ventilation (1,2), no study has reported an impact of VA ECMO settings on diaphragm effort. We hypothesized that ECMO sett...

Little is known about hemostasis modifications induced by chronic hypoxic exposure in high-altitude residents, especially in those who develop excessive erythrocytosis (EE, i.e. hemoglobin concentration ≥ 21 g·dL-1 in male and ≥ 19 g·dL-1 in female). The aim of this preliminary study was to assess coagulation alterations in highlanders with or with...

Background While millions of people are living permanently at high altitude (>2,500 m) worldwide, the mechanisms underlying their tolerance to chronic hypoxia and those responsible for the occurrence of chronic mountain sickness (CMS) remain to be elucidated. Excessive erythrocytosis (EE) is thought to be the main mechanism responsible for CMS symp...

The diagnosis of chronic mountain sickness (CMS) is based on a score including 7 clinical features (breathlessness, sleep disturbance, cyanosis, venous dilatation, paresthesia, headache, and tinnitus) in the setting of extreme erythrocytosis. Examining individuals in La Rinconada, Peru, the highest city in the world, the authors demonstrated that C...

Background: While severe intermittent hypoxia (IH) is well known to induce deleterious cardiometabolic consequences, moderate IH may induce positive effects in obese individuals. The present study aimed to evaluate the effect of two hypoxic conditioning programs on cardiovascular and metabolic health status of overweight or obese individuals. Met...

Exercise intolerance is characteristically multi-factorial in patients with COPD. At least in symptomatic patients with moderate-to-severe airflow limitation, higher operating lung volumes assume a relevant role in decreasing patients’ tolerance to sustain “prolonged” exercise. As a consequence of the dynamic increase in the end-expiratory lung vol...

The development of wearable devices for healthcare monitoring is of primary interest, in particular for homecare applications. But it is challenging to develop an evaluation framework to test and optimize such a device by following a non-invasive protocol. As well established reference devices do exist for capnometry, we propose a protocol to evalu...

Key points: Highlanders developed unique adaptative mechanisms to chronic hypoxic exposure, including substantial haemoglobin and haematocrit increases. A significant proportion of populations living permanently at high altitude developed however maladaptive features known as chronic mountain sickness (CMS). This study aimed to assess the effects...