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Forensic Pathophysiology of Asphyxial Death
Published in Sudhir K. Gupta, Forensic Pathology of Asphyxial Deaths, 2022
Asphyxial deaths include death due to deficiency of oxygen in the respired air, such as cases of sewage tank cleaning accidents and ‘ghost well’ deaths. Peculiar postmortem findings and analysis of composition of gases obtained from various levels can be useful in reaching a reasonable conclusion about cause and manner of death in these cases. Hypoxia due to high altitude may lead to death of an individual, in whom acclimatization has been not achieved properly. Postmortem findings along with history and other circumstantial evidences will be helpful for the autopsy surgeon to give a scientific opinion for concluding these cases. Inhalation of excess quantity of toxic gases like carbon monoxide, carbon dioxide, hydrogen sulfide, etc. can also result in fatal tissue hypoxia. Carefully and systematically conducted autopsies along with a logical evaluation of the circumstances will be needed in similar cases where the postmortem findings such as the ‘typical’ color variation of postmortem hypostasis due to different toxic gases are subjective and are hardly even evident in many cases due to the relatively darker complexion of certain races.
Acclimatization
Published in Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson, Ward, Milledge and West's High Altitude Medicine and Physiology, 2021
Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson
To mountaineers, acclimatization is the process by which they become more comfortable at altitude and find they can perform better than when they first arrived (Houston 1955; Roach 2019). The concept is nicely encapsulated by a statement from Charles Houston (1955), who, following decades of experience climbing at very high altitudes, wrote: “There is an altitude frontier beyond which humans cannot become accustomed to oxygen lack, but the approach to that frontier … is made possible by acclimatization—the process of becoming accustomed to an environment foreign to the organism.” For individuals traveling to high altitude, acclimatization prevents or alleviates symptoms and signs of acute altitude illness and restoration of some of the exercise performance lost on arrival at altitude (Latshang et al. 2013; Subudhi et al. 2014), whereas for physiologists, altitude acclimatization is, strictly, the sum of all the beneficial changes in response to altitude hypoxia that occur with time spent at a given altitude, and that eventually disappear on descent to low altitude. It refers only to the changes in response to hypoxia seen as beneficial as opposed to changes that result in illnesses such as acute mountain sickness (AMS), high altitude cerebral edema (HACE), or high altitude pulmonary edema (HAPE) and are considered pathological.
Basic Thermal Physiology: What Processes Lead to the Temperature Distribution on the Skin Surface
Published in Kurt Ammer, Francis Ring, The Thermal Human Body, 2019
The terms acclimation and acclimatization are etymologically indistinguishable. Both words have been assigned several and different meanings [146]. The most useful of the assigned meanings, adopted here, would seem to be those of Hart [147] and Eagan [148] who use the term acclimation to describe the adaptive changes that occur within an organism in response to experimentally induced changes in particular climatic factors such as ambient temperature in a controlled environment, and the term acclimatization to describe the adaptive changes that occur within an organism in response to changes in the natural climate [2]. Consequently, acclimatization was defined as the process by which a living organism becomes adapted to a change of climatic environment [145]. Acclimatization is a relatively quick adaptation that occurs within the organism’s lifetime [2]. Traditionally, acclimatization studies in humans have focused on adapting to temperature changes (such as moving from a temperate climate to the tropics), but acclimatization can also occur with a change in altitude, photoperiod and humidity, for instance [145].
Human cold habituation: Physiology, timeline, and modifiers
Published in Temperature, 2022
Beau R. Yurkevicius, Billie K. Alba, Afton D. Seeley, John W. Castellani
The following are definitions of the general terms used in this review, as defined by the International Union of Physiological Sciences [9]. The term adaptation is used to describe “changes that reduce the physiological strain produced by stressful components of the total environment”. The terms acclimation and acclimatization are often used interchangeably to refer to any adaptive change which occurs due to prolonged or repeated exposure to a stressful environment, and which reduces the strain or enhances endurance of strain in that environment. The terms differ slightly in that acclimation refers to experimentally driven or lab-based exposures, while acclimatization refers to natural exposures due to climate, season, or location. Habituation is defined as a “reduction of responses to or perception of a repeated stimulation.” In the context of this review, adaptation will be used as a general term, acclimation and acclimatization will be used to differentiate exposure type within the profiled studies, and habituation will be used to describe a reduction in the typical responses observed during acute cold exposures.
Inclusion of resistance routines in a hypoxia training program does not interfere with prevention of acute mountain sickness
Published in The Physician and Sportsmedicine, 2021
Aritz Urdampilleta, Patxi León-Guereño, Julio Calleja-González, Enrique Roche, Juan Mielgo-Ayuso
There are several techniques to simulate the effects of high altitudes. Some are based on artificially decreasing partial oxygen concentration in the air (normobaric hypoxia) accompanied alternatively by barometric pressure decrease (hypobaric hypoxia) [15]. However, there are certain discrepancies as to what are the adequate pre-acclimatization protocols [2]. The majority of protocols include simulated altitudes of 4000–5500 m, with daily light endurance exercise sessions for 1.5–4 h lasting during 9–21days [16,17]. Using this approach, results are quite similar to those obtained staying in the mountain at 4300 m [18]. These studies have observed a significant improvement of several physiological parameters and a reduction of AMS incidence and severity. Likewise, these pre-acclimatization programs concluded that, in order to improve respiratory function and decrease AMS prevalence, it is necessary to perform at least an endurance training program of 1 h/day at 4000 m of simulated altitude [2].
Physiological and oxidative stress responses to intermittent hypoxia training in Sprague Dawley rats
Published in Experimental Lung Research, 2020
Megha A. Nimje, Himadri Patir, Rajesh Kumar Tirpude, Prasanna K. Reddy, Bhuvnesh Kumar
The natural countermeasures to the altitude-induced physical performance decrements and AMS are altitude acclimatization. Lowlanders who continuously reside at high altitude develop a variety of physiological adaptations during altitude acclimatization. Acclimatization to a target altitude can be induced by slow progressive ascents or continuous stays at intermediate altitudes. However, altitude acclimatization is a very time and resource consuming process and doesn’t suit to the activities which require urgent attention. Depending on the altitude to which a previously unacclimatized lowlander has descended, the time course for altitude acclimatization is 4-11 days.10 In military point of view, this altitude residency requirement drastically reduces the utilization of military personnel in rapid response military missions that exploit the air mobility capability of modern military forces to quickly deploy to an area of operations on short notice.