Hypoxic ventilatory response (HVR) is the increase in ventilation induced by hypoxia that allows the body to take in and transport lower concentrations of oxygen at higher rates. It is initially elevated in lowlanders who travel to high altitude, but reduces significantly over time as people acclimatize.[1][2] In biological anthropology, HVR also refers to human adaptation to environmental stresses resulting from high altitude.[3]
In mammals, HVR invokes several physiological mechanisms. It is a direct result of the decrease in partial pressure of oxygen in arterial blood, and leads to increased ventilation. The body has different ways of coping with acute hypoxia. Mammals that rely on pulmonary ventilation will increase their ventilation to account for the lack of oxygen reaching the tissues.[2] Mammals will also experience decreases in aerobic metabolism and oxygen demand, along with increases in ATP production.
The physiological mechanisms differ in effect and in course of time. HVR is time dependent and can be divided into two phases: the first (0–5 minutes) of ventilation increase, and the second (5–20 minutes) of slow decline.[4]
The initial increase in ventilation from HVR is initiated by the carotid bodies, which are bilaterally located at the port of brain circulation.[2] Carotid bodies contain oxygen-sensitive cells that become more active in response to hypoxia. They send input to the brainstem which is then processed by respiratory centers. Other mechanisms include hypoxia-inducible factors, particularly HIF1.[2] Hormonal changes have also been associated with HVR, particularly those that affect the functioning of the carotid bodies.[5]
As HVR is a response to decreased oxygen availability,[1] it shares the same environmental triggers as hypoxia. Such precursors include travelling to high altitude locations[6] and living in an environment with high levels of carbon monoxide.[7] Combined with climate, HVR can affect fitness and hydration.[2] Especially for lowlanders who traverse past 6000 meters in altitude, the limit of prolonged human exposure to hypoxia, HVR may result in hyperventilation and ultimately the deterioration of the body. Oxygen consumption is reduced to a maximum of 1 liter per minute.[8]
Travelers acclimatized to high altitudes exhibit high levels of HVR, as it provides advantages such as increased oxygen intake, enhanced physical and mental performance, and lower susceptibility to illnesses associated with high altitude.[1] Adaptations in populations living at high altitudes range from cultural to genetic, and vary among populations. For example, Tibetans living at high altitudes have a more sensitive hypoxic ventilatory response than do Andean peoples living at similar altitudes,[5][9] even though both populations exhibit greater aerobic capacity compared to lowlanders.[10] The cause of this difference is most likely genetic, although developmental factors may also contribute.[10]
^ abcCymerman, A; Rock, PB. "Medical Problems in High Mountain Environments. A Handbook for Medical Officers"[usurped]. USARIEM-TN94-2. US Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report. Retrieved 2009-03-05.
^ abcdeTeppema, Luc J., and Albert Dahan. "The ventilatory response to hypoxia in mammals: mechanisms, measurement, and analysis." Physiological Reviews 90.2 (2010): 675-754.
^Stanford, Craig, John S. Allen, and Susan C. Anton. Biological Anthropology : The Natural History of Humankind. 2nd ed. Upper Saddle River: Prentice Hall Higher Education, 2008. 151-52.
^Duffin, James (1 October 2007). "Measuring the ventilatory response to hypoxia". The Journal of Physiology. 584 (Pt 1): 285–293. doi:10.1113/jphysiol.2007.138883. ISSN 0022-3751. PMC 2277066. PMID 17717019.
^ abHornbein, Thomas F., and Robert B. Schoene. High Altitude: An Exploration Of Human Adaptation. n.p., New York: Marcel Dekker, c2001., 2001. OskiCat. Web. 8 Nov. 2016.
^"Altitude Hypoxia Explained." Archived 10 November 2016 at the Wayback Machine Altitude Research Center. Altitude Research Center, n.d. Web. 08 Nov. 2016.
^Karius, Diane R. "Respiratory Adaptations in Health and Disease: Forms of Hypoxia." Forms of Hypoxia. Kansas City University, n.d. Web. 08 Nov. 2016.
^West John B (2006). "Human responses to extreme altitudes". Integrative and Comparative Biology. 46 (1): 25–34. doi:10.1093/icb/icj005. PMID 21672720.
^Beall Cynthia M. "Tibetan and Andean patterns of adaptation to high-altitude hypoxia". Human Biology. 2000: 201–228.
^ abHochachka Peter W.; Christian Gunga Hanns; Kirsch Karl (1998). "Our ancestral physiological phenotype: An adaptation for hypoxia tolerance and for endurance performance?". Proceedings of the National Academy of Sciences. 95 (4): 1915–1920. Bibcode:1998PNAS...95.1915H. doi:10.1073/pnas.95.4.1915. PMC 19213. PMID 9465117.
and 25 Related for: Hypoxic ventilatory response information
Hypoxicventilatoryresponse (HVR) is the increase in ventilation induced by hypoxia that allows the body to take in and transport lower concentrations...
been observed to counteract some age-related decline in the hypoxicventilatoryresponse as tested by inducing prolonged hypoxia. Although N-acetylcysteine...
polycythemia – Laboratory diagnosis of high hemoglobin content in blood Hypoxicventilatoryresponse – Biological reaction to increased altitude Decompression sickness –...
Tibetans. Physiological conditions such as resting ventilation, hypoxicventilatoryresponse, oxygen saturation, and haemoglobin concentration are significantly...
Hypervariable region, a location within nuclear or mitochondrial DNA Hypoxicventilatoryresponse This disambiguation page lists articles associated with the title...
Qureshi, T.; Anthouard, M.N.; Mateika, J.H. (2011). "The hypoxicventilatoryresponse and ventilatory long-term facilitation are altered by time of day and...
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas...
body chemoreceptors are sometimes not enough to ensure appropriate ventilatoryresponse; SIDS deaths occur most frequently during the days or weeks in which...
to airway obstruction and increased risk of aspiration. The hypoxicventilatoryresponse (HRV) can also be severely depressed as well leading to hypoxemia...
Eriksson LI, Lindahl SG (February 2003). "Hypercarbic and hypoxicventilatoryresponses after intrathecal administration of bupivacaine and sameridine"...
coughing and laryngospasm. It reduces the ventilatoryresponse to hypoxia and hypercapnia, and impedes hypoxic pulmonary vasoconstriction. Sevoflurane vasodilatory...
relatively mild acidosis and reduced ventilatoryresponse in a vicious circle. Low oxygen levels lead to hypoxic pulmonary vasoconstriction, the tightening...
with ventilatory support and other appropriate active substances, is indicated: for the treatment of newborn infants ≥34 weeks gestation with hypoxic respiratory...
helium was substituted for nitrogen at 4 atm (400 kPa). Inadequate ventilatoryresponse to exertion was indicated by the fact that, despite resting values...
gas supply type: constant flow, supply on demand, or supplemental, by ventilatory driving force: the breathing effort of the user, or mechanical work from...
device, or a mechanical ventilator. Once there is no longer a need for ventilatory assistance or protection of the airway, the tracheal tube is removed;...
because of obstruction and/or destruction, will become hypoxic and an inflammatory response may consequently occur. Partial obstruction will lead to...
subarachnoid hemorrhage, ischemic infarctions in susceptible areas of the brain, hypoxic-ischemic encephalopathy, unexplained coma, and brain death. Bleeding occurs...
family, can use gill remodelling to increase oxygen uptake in hypoxic environments. The response of naked carp to cold and low-oxygen conditions seem to be...
to ascend to a shallower depth. Use of nitrox may cause a reduced ventilatoryresponse, and when breathing dense gas at the deeper limits of the usable...
breathe is primarily based on carbon dioxide concentration, and ventilatoryresponse to increased carbon dioxide is known to be lower in seals than terrestrial...
Also, if breathing is hypoxic, the bird can use CO2/pH-sensitive chemoreceptors to restrain breathing. Due to ventilatoryresponses, this process leads...
behavioral in response to the hypoxia. Some fish will go upwards to find more oxygenated water, and some enter a phase of metabolic and ventilatory depression...
to increased density of the breathing das with depth. Inadequate ventilatoryresponse to exertion. Dead space of the breathing apparatus. Higher inspired...
Global Information