Adaptive Responses to Hypoxia and/or Hyperoxia in Humans

Antioxidants and Redox Signaling, Journal Year: 2022, Volume and Issue: 37(13-15), P. 887 - 912

Published: Feb. 1, 2022

Significance: Oxygen is indispensable for aerobic life, but its utilization exposes cells and tissues to oxidative stress; thus, tight regulation of cellular, tissue, systemic oxygen concentrations crucial. Here, we review the current understanding how human organism (mal-)adapts low (hypoxia) high (hyperoxia) levels these adaptations may be harnessed as therapeutic or performance enhancing strategies at level. Recent Advances: Hyperbaric therapy already a cornerstone modern medicine, application mild hypoxia, that is, hypoxia conditioning (HC), strengthen resilience organs whole body severe hypoxic insults an important preparation high-altitude sojourns protect cardiovascular system from hypoxic/ischemic damage. Many other applications hypo- and/or hyperoxia are only just emerging. HC-sometimes in combination with hyperoxic interventions-is gaining traction treatment chronic diseases, including numerous neurological disorders, enhancement. Critical Issues: The dose- intensity-dependent effects varying render hypoxia- hyperoxia-based interventions potentially highly beneficial, yet hazardous, although risks versus benefits ill-defined. Future Directions: field expanding rapidly, novel increasingly recognized, example, modulation aging processes, mood metabolic diseases. To advance hypoxia/hyperoxia clinical applications, more research on intensity, duration, frequency altered concentrations, well individual vulnerabilities such interventions, paramount. Antioxid. Redox Signal. 37, 887-912.

Language: Английский

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Impact of High Altitude on Cardiovascular Health: Current Perspectives

Vascular Health and Risk Management, Journal Year: 2021, Volume and Issue: Volume 17, P. 317 - 335

Published: June 1, 2021

Abstract: Globally, about 400 million people reside at terrestrial altitudes above 1500 m, and more than 100 lowlanders visit mountainous areas 2500 m annually. The interactions between the low barometric pressure partial of O 2 , climate, individual genetic, lifestyle socio-economic factors, as well adaptation acclimatization processes high elevations are extremely complex. It is challenging to decipher effects these myriad factors on cardiovascular health in altitude residents, even so those ascending with or without preexisting diseases. This review aims interpret epidemiological observations high-altitude populations; present discuss responses acute subacute exposure general specifically diseases; relations pathologies neurodegenerative diseases altitude; exercise; putative cardioprotective mechanisms hypobaric hypoxia. Keywords: hypoxia, hypobaria, exercise, adaptation, acclimatization, conditioning

Language: Английский

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High-altitude illnesses: Old stories and new insights into the pathophysiology, treatment and prevention

Sports Medicine and Health Science, Journal Year: 2021, Volume and Issue: 3(2), P. 59 - 69

Published: April 19, 2021

Areas at high-altitude, annually attract millions of tourists, skiers, trekkers, and climbers. If not adequately prepared considering certain ascent rules, a considerable proportion those people will suffer from acute mountain sickness (AMS) or even life-threatening high-altitude cerebral (HACE) or/and pulmonary edema (HAPE). Reduced inspired oxygen partial pressure with gain in altitude consequently reduced availability is primarily responsible for getting sick this setting. Appropriate acclimatization by slowly raising the hypoxic stimulus (e.g., slow to high altitude) and/or repeated exposures artificial, normobaric hypoxia largely prevent illnesses. Understanding physiological mechanisms pathophysiological diseases, knowledge symptoms signs, treatment prevention strategies contribute risk reduction increased safety, success enjoyment altitude. Thus, review intended provide sound basis both physicians counseling visitors themselves.

Language: Английский

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Effects of Intermittent Hypoxia–Hyperoxia on Performance- and Health-Related Outcomes in Humans: A Systematic Review

Sports Medicine - Open, Journal Year: 2022, Volume and Issue: 8(1)

Published: May 31, 2022

Intermittent hypoxia applied at rest or in combination with exercise promotes multiple beneficial adaptations regard to performance and health humans. It was hypothesized that replacing normoxia by moderate hyperoxia can increase the adaptive response intermittent hypoxic stimulus.

Language: Английский

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Intermittent Hypoxia Conditioning: A Potential Multi-Organ Protective Therapeutic Strategy

International Journal of Medical Sciences, Journal Year: 2023, Volume and Issue: 20(12), P. 1551 - 1561

Published: Jan. 1, 2023

Severe hypoxia can induce a range of systemic disorders; however, surprising resilience be obtained through sublethal adaptation to hypoxia, process termed as hypoxic conditioning.A particular form this strategy, known intermittent conditioning hormesis, alternates exposure and normoxic conditions, facilitating reduced oxygen availability.This technique, originally employed in sports high-altitude medicine, has shown promise multiple pathologies when applied with calibrated mild moderate appropriate cycles.Recent studies have extensively investigated the protective role its underlying mechanisms using animal models, demonstrating potential organ protection.This involves processes such reduction oxidative stress, inflammation, apoptosis, along enhancement gene expression, among others.Given that fosters beneficial physiological responses across organs systems, review presents comprehensive analysis existing on advantages various organs.It aims draw attention possibility clinically applying multi-organ strategy.This comprehensively discusses effects outlines procedures for implementing provides brief overview hypoxia.

Language: Английский

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Hypoxia Conditioning for High-Altitude Pre-acclimatization

Journal of Science in Sport and Exercise, Journal Year: 2022, Volume and Issue: 4(4), P. 331 - 345

Published: Jan. 9, 2022

Abstract Purpose Main purposes of pre-acclimatization by hypoxia conditioning (HC) are the prevention high-altitude illnesses and maintenance aerobic exercise performance. However, robust evidence for those effects or evidence-based guidelines exposure strategies, including recommendations to ensure safety, largely lacking. Therefore, we summarize current knowledge on physiology acclimatization HC with aim derive implications strategies before going treks expeditions. Methods Based literature search personal experience, core studies important observations have been selected in order present a balanced view process, specifically focusing HC. Results Conclusions It may be concluded that certain cases even short periods (e.g., 7 h) effective, but longer > 60 needed elicit more effects. About 300 h (intermittently applied) optimal preparation extreme altitude sojourns, although every additional hour spent confer further benefits. The inclusion hypobaric exposures (i.e., real altitude) protocols could increase their efficacy. level simulated is progressively increased individually adjusted ideally. should not terminated earlier than 1–2 weeks sojourn. Medical monitoring program strongly recommended.

Language: Английский

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Altitude, Exercise, and Skeletal Muscle Angio-Adaptive Responses to Hypoxia: A Complex Story

Frontiers in Physiology, Journal Year: 2021, Volume and Issue: 12

Published: Sept. 6, 2021

Hypoxia, defined as a reduced oxygen availability, can be observed in many tissues response to various physiological and pathological conditions. As hallmark of the altitude environment, ambient hypoxia results from drop pressure atmosphere with elevation. A hypoxic stress also occur at cellular level when supply through local microcirculation cannot match cells’ metabolic needs. This has been suggested contracting skeletal myofibers during physical exercise. Regardless its origin, or exercise-induced, muscle triggers complex angio-adaptive responses tissue. These result expression plethora molecules, ultimately leading growth, stabilization, regression capillaries. remarkable plasticity capillary network is referred angio-adaptation. It alter capillary-to-myofiber interface, which represent an important determinant function. molecules released circulation myokines act on distant tissues. review addresses respective combined potency exercise generate muscle. The major so far described this context will discussed, including existing controversies field. Finally, highlight molecular complexity identify current gaps knowledges field environmental physiology.

Language: Английский

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Independent effects of acute normobaric hypoxia and hypobaric hypoxia on human physiology

Scientific Reports, Journal Year: 2022, Volume and Issue: 12(1)

Published: Nov. 15, 2022

Abstract The purpose of this study was to examine the effects acute normobaric (NH, decreased FiO 2 ) and hypobaric (HH, 4200 m ascent) hypoxia exposures compared sea level (normobaric normoxia, NN). Tissue oxygenation, cardiovascular, body fluid variables measured during rest a 3-min step-test following 90-min HH, Muscle oxygenated hemoglobin (O Hb) decreased, muscle deoxygenated (HHb) increased environmentally independent from exercise ( p < 0.001). During exercise, brain O Hb lower at HH NN = 0.007), trending similarly with NH 0.066), but no difference between 0.158). HR (141 ± 4 beats·min −1 3 were higher than (127 44 , 0.002), not each other 0.208). stroke volume (109.6 4.1 mL·beat (97.8 3.3 (99.8 3.9 ≤ 0.010) 0.481). cardiac output (13.8 0.6 L) (15.5 0.7 (12.6 0.5 L, 0.006) also hypoxic stimuli, skeletal maintains oxygenation whereas does not. These differences may be mediated by specific cardiovascular compensation. Thus, caution is advised when equating HH.

Language: Английский

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Thoracic load carriage impairs the acute physiological response to hypoxia in healthy males

Physiological Reports, Journal Year: 2025, Volume and Issue: 13(1)

Published: Jan. 1, 2025

Abstract To assess the impact of thoracic load carriage on physiological response to exercise in hypoxia. Healthy males ( n = 12) completed 3 trials consisting 45 min walking following conditions: (1) unloaded normoxia (UN; F I O 2 :20.93%); (2) hypoxia (UH; :~13.0%); and (3) loaded (LH; 29.5 kg; :~13.0%). Intensity was matched for absolute VO (2.0 ± 0.2 L·min −1 ) across conditions relative (64.0 2.6 %VO 2max hypoxic conditions. With LH versus UH, there were increases breathing frequency (5–11 breaths·min ; p < 0.05) decreases tidal volume (10%–18%; throughout due reductions end inspiratory lung volumes 0.05). Consequently, deadspace (11%–23%; minute ventilation (7%–11%; increased starting at 20 30 min, respectively. In addition, perceived exertion/dyspnea induced (~12%; 0.05 vs. UN) expiratory (~10%; pre‐exercise) respiratory muscle fatigue. Expiratory flow limitation present 50% subjects during LH. Cardiac output oxygenation maintained despite reduced stroke (6%–8%; Finally, cerebral oxygenated/total hemoglobin elevated condition UH 15 Thoracic strain interferes with compensatory exposure.

Language: Английский

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Hypoxia and hemorheological properties in older individuals

Ageing Research Reviews, Journal Year: 2022, Volume and Issue: 79, P. 101650 - 101650

Published: May 18, 2022

Language: Английский

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