Basic Thermal Physiology: What Processes Lead to the Temperature Distribution on the Skin Surface
Kurt Ammer, Francis Ring in 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].
Acclimatization
Andrew M. Luks, Philip N. Ainslie, Justin S. Lawley, Robert C. Roach, Tatum S. Simonson in Ward, Milledge and West's High Altitude Medicine and Physiology, 2021
The major benefits of acclimatization are to protect against acute altitude illness (Subudhi et al. 2014), to improve cognitive performance to near sea-level values (Roach et al. 2014), and to boost submaximal exercise performance (Fulco et al. 2005; Horstman et al. 1980; Latshang et al. 2013; Subudhi et al. 2014) without changing peak oxygen consumption (Beidleman et al. 1997; Calbet et al. 2003a; Calbet et al. 2003b; Calbet et al. 2004; Fulco et al. 2002; Fulco et al. 2005; Lundby et al. 2004; Lundby et al. 2007; Sutton et al. 1988; Wolfel et al. 1991). To understand the effects of acclimatization on exercise, tests of submaximal endurance are more useful than peak oxygen consumption or all-out time trial performance over a short distance, as high altitude travelers rarely perform at these levels of exertion. For example, mountaineers try to preserve energy to sustain efforts across multiple days and might actually put themselves at risk of serious harm, or death, if they truly reached the point of exhaustion. Their ability to cover more ground faster while preserving a functional reserve is a hallmark of acclimatization supported by anecdotal accounts (Houston 2005; Messner 1989). Despite this, the physiology behind the improvement in sustained, self-regulated submaximal performance at altitude remains unexplored.
Applied exercise physiology and the environment
Nick Draper, Helen Marshall in Exercise Physiology, 2014
Adaptation to altitude can be simulated in a laboratory, known as acclimation, or brought about by a period spent living at altitude (acclimatisation). Full acclimatisation to high altitude appears to take around two weeks, with another week required for each further 600 m increment of ascent. It is brought about by a range of respiratory, cardiovascular and metabolic adaptations to the reduced PO2. Alkalosis brought about through hyperventilation (which remains elevated even during prolonged stays at altitude) is compensated for by increases in the excretion of bicarbonate (HCO3−). The decrease in blood bicarbonate associated with reducing respiratory alkalosis is thought to be partly responsible for the decreased anaerobic performance and reduced lactate concentration experienced during prolonged stays at altitude. The decrease in blood bicarbonate concentration, however, restores the acid-base balance in the blood.
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.
Divers risk accelerated fatigue and core temperature rise during fully-immersed exercise in warmer water temperature extremes
Published in Temperature, 2019
David P. Looney, Edwin T. Long, Adam W. Potter, Xiaojiang Xu, Karl E. Friedl, Reed W. Hoyt, Christopher R. Chalmers, Mark J. Buller, John P. Florian
One limitation of this investigation is that treatment order was not randomized. Trials were scheduled in ascending order of Tw and were scheduled at least 3 days after a resting trial at the designated Tw to best ensure diver safety and minimize heatstroke risk. Acclimatization status is a prominent moderator of the effect of environmental heat stress on endurance exercise performance [32]. Consequently, the treatment order may have blunted the thermoregulatory responses observed in the higher Tw conditions. Another limitation for this investigation is the lack of skin temperature data which is essential for tracking the time course of the inversion of the skin-water temperature gradient. High skin temperatures are associated with earlier exhaustion during submaximal exercise in the heat [33–35]. This performance decrement has been attributed to reductions in cardiac output and peak oxygen uptake resulting from increased peripheral blood flow [33].
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.
Related Knowledge Centers
- Adaptation
- Denaturation
- Membrane Protein
- Ph
- Photoperiodism
- Cell Membrane
- Fitness
- Fur
- Heat Shock Protein
- Chaperone