Altitude et système cardiovasculaire

Richalet, Jean‐Paul

doi:10.1016/j.lpm.2012.02.003

Cited by 12 publications

(7 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TET is widely used for the estimation of exercise intensity in hospitals. In addition, exercise tests are commonly used on site and at equivalent altitudes (Richalet, 2012). Therefore, TET could be Recovery-RPP6min 1 0.000 0.000 1.360 0.244 1.000 (0.999-1.000)…”

Section: Discussionmentioning

confidence: 99%

RETRACTED: Altitude Cardiomyopathy Is Associated With Impaired Stress Electrocardiogram and Increased Circulating Inflammation Makers

et al. 2021

View full text Add to dashboard Cite

Many sea-level residents suffer from acute mountain sickness (AMS) when first visiting altitudes above 4,000 m. Exercise tolerance also decreases as altitude increases. We observed exercise capacity at sea level and under a simulated hypobaric hypoxia condition (SHHC) to explore whether the response to exercise intensity represented by physiological variables could predict AMS development in young men. Eighty young men from a military academy underwent a standard treadmill exercise test (TET) and biochemical blood test at sea level, SHHC, and 4,000-m altitude, sequentially, between December 2015 and March 2016. Exercise-related variables and 12-lead electrocardiogram parameters were obtained. Exercise intensity and AMS development were investigated. After exposure to high altitude, the count of white blood cells, alkaline phosphatase and serum albumin were increased (P < 0.05). There were no significant differences in exercise time and metabolic equivalents (METs) between SHHC and high-altitude exposures (7.05 ± 1.02 vs. 7.22 ± 0.96 min, P = 0.235; 9.62 ± 1.11 vs. 9.38 ± 1.12, P = 0.126, respectively). However, these variables were relatively higher at sea level (8.03 ± 0.24 min, P < 0.01; 10.05 ± 0.31, P < 0.01, respectively). Thus, subjects displayed an equivalent exercise tolerance upon acute exposure to high altitude and to SHHC. The trends of cardiovascular hemodynamics during exercise under the three different conditions were similar. However, both systolic blood pressure and the rate–pressure product at every TET stage were higher at high altitude and under the SHHC than at sea level. After acute exposure to high altitude, 19 (23.8%) subjects developed AMS. Multivariate logistic regression analysis showed that METs under the SHHC {odds ratio (OR) 0.355 per unit increment [95% confidence intervals (CI) 0.159−0.793], P = 0.011}, diastolic blood pressure (DBP) at rest under SHHC [OR 0.893 per mmHg (95%CI 0.805−0.991), P = 0.030], and recovery DBP 3 min after exercise at sea level [OR 1.179 per mmHg (95%CI 1.043−1.333), P = 0.008] were independently associated with AMS. The predictive model had an area under the receiver operating characteristic curve of 0.886 (95%CI 0.803−0.969, P < 0.001). Thus, young men have similar exercise tolerance in acute exposure to high altitude and to SHHC. Moreover, AMS can be predicted with superior accuracy using characteristics easily obtainable with TET.

show abstract

Section: Discussionmentioning

confidence: 99%

RETRACTED: Altitude Cardiomyopathy Is Associated With Impaired Stress Electrocardiogram and Increased Circulating Inflammation Makers

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Previous studies, such as those carried out by Boos et al [ 19 ], are consistent with our results and note that this effect is observed in all forms of acute intermittent hypobaric hypoxia. A possible mechanism inducing this effect is the increase in the sympathetic tone described within the acclimatization processes to hypobaric hypoxia [ 24 , 25 ], which would generate both an increase in chrono-tropism and inotropism [ 26 ]. Within these effects, β-adrenergic agonism increases the second messenger cyclic adenosine monophosphate (cAMP), which binds to and activates a cAMP-dependent protein kinase (PKA).…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Cardiovascular Protection Associated with Intermittent Hypobaric Hypoxia Exposure in a Rat Model: Role of Oxidative Stress

Aguilar

Gonzaléz‐Candia

Rodríguez

et al. 2018

IJMS

View full text Add to dashboard Cite

More than 140 million people live and works (in a chronic or intermittent form) above 2500 m worldwide and 35 million live in the Andean Mountains. Furthermore, in Chile, it is estimated that 55,000 persons work in high altitude shifts, where stays at lowlands and interspersed with working stays at highlands. Acute exposure to high altitude has been shown to induce oxidative stress in healthy human lowlanders, due to an increase in free radical formation and a decrease in antioxidant capacity. However, in animal models, intermittent hypoxia (IH) induce preconditioning, like responses and cardioprotection. Here, we aimed to describe in a rat model the responses on cardiac and vascular function to 4 cycles of intermittent hypobaric hypoxia (IHH). Twelve adult Wistar rats were randomly divided into two equal groups, a four-cycle of IHH, and a normobaric hypoxic control. Intermittent hypoxia was induced in a hypobaric chamber in four continuous cycles (1 cycle = 4 days hypoxia + 4 days normoxia), reaching a barometric pressure equivalent to 4600 m of altitude (428 Torr). At the end of the first and fourth cycle, cardiac structural, and functional variables were determined by echocardiography. Thereafter, ex vivo vascular function and biomechanical properties were determined in femoral arteries by wire myography. We further measured cardiac oxidative stress biomarkers (4-Hydroxy-nonenal, HNE; nytrotirosine, NT), reactive oxygen species (ROS) sources (NADPH and mitochondrial), and antioxidant enzymes activity (catalase, CAT; glutathione peroxidase, GPx, and superoxide dismutase, SOD). Our results show a higher ejection and shortening fraction of the left ventricle function by the end of the 4th cycle. Further, femoral vessels showed an improvement of vasodilator capacity and diminished stiffening. Cardiac tissue presented a higher expression of antioxidant enzymes and mitochondrial ROS formation in IHH, as compared with normobaric hypoxic controls. IHH exposure determines a preconditioning effect on the heart and femoral artery, both at structural and functional levels, associated with the induction of antioxidant defence mechanisms. However, mitochondrial ROS generation was increased in cardiac tissue. These findings suggest that initial states of IHH are beneficial for cardiovascular function and protection.

show abstract

“…Various studies indicate that the systemic blood pressure in adult highland natives is lower than that is in the lowland natives at sea level (Hooper and Mellor, ; Richalet, ). Among highland natives, the frequency of systemic hypertension and ischemic heart disease is also significantly lower than among lowland natives at sea level, as well as a lowering of 10 mm Hg or more in systolic and diastolic pressures in lowland subjects who resided for a long time (2–15 years) at high altitude (Marticorena et al, ).…”

Section: Adaptive Pathwaysmentioning

confidence: 99%

Developmental Functional Adaptation to High Altitude: Review

Frisancho

2013

American J Hum Biol

106

View full text Add to dashboard Cite

Various approaches have been used to understand the origins of the functional traits that characterize the Andean high-altitude native. Based on the conceptual framework of developmental functional adaptation which postulates that environmental influences during the period of growth and development have long lasting effects that may be expressed during adulthood, we initiated a series of studies addressed at determining the pattern of physical growth and the contribution of growth and development to the attainment of full functional adaptation to high-altitude of low and high altitude natives living under rural and urban conditions. Current research indicate that: (a) the pattern of growth at high altitude due to limited nutritional resources, physical growth in body size is delayed but growth in lung volumes is accelerated because of hypoxic stress); (b) low-altitude male and female urban natives can attain a full functional adaptation to high altitude by exposure to high-altitude hypoxia during the period of growth and development; (c) both experimental studies on animals and comparative human studies indicate that exposure to high altitude during the period of growth and development results in the attainment of a large residual lung volume; (d) this developmentally acquired enlarged residual lung volume and its associated increase in alveolar area when combined with the increased tissue capillarization and moderate increase in red blood cells and hemoglobin concentration contributes to the successful functional adaptation of the Andean high-altitude native to hypoxia; and (e) any specific genetic traits that are related to the successful functional adaptation of Andean high-altitude natives have yet to be identified.

show abstract

Altitude et système cardiovasculaire

Cited by 12 publications

References 15 publications

RETRACTED: Altitude Cardiomyopathy Is Associated With Impaired Stress Electrocardiogram and Increased Circulating Inflammation Makers

RETRACTED: Altitude Cardiomyopathy Is Associated With Impaired Stress Electrocardiogram and Increased Circulating Inflammation Makers

Mechanisms of Cardiovascular Protection Associated with Intermittent Hypobaric Hypoxia Exposure in a Rat Model: Role of Oxidative Stress

Developmental Functional Adaptation to High Altitude: Review

Contact Info

Product

Resources

About