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PubMed2005

Mood states during a successful world record underwater diving attempt.

The mood states of a diver were recorded over a period of almost 10 days of submersion. Scores on the Profile of Mood States obtained on the components of Depression, Anger, and Confusion suggested that there were no signs of psychological disintegration over this period. As expected, scores on Fatigue increased whereas perceived Vigor diminished over time. High Esteem remained consistent. It is proposed that profiling of mood states can be a useful monitoring tool of an acclimatization process.

Acclimatization↗
PubMed1990

Oxygen uptake and transport in the human organism on the summit of Mt. Everest.

In May 1978 the two Italians, Messner and Habeler, climbed to the summit of Mt. Everest (8848 m above sea level) without use of supplementary oxygen. This must be the extreme limit of what the human organism can do. The upper limit of permanent living for man is considered to be about 5300 m above sea level. The fact that man not only can remain conscious on the summit of Mt. Everest, but climb there without supplementary oxygen is due to a number of changes that take place over a period of hours to months at high altitudes. These changes are termed acclimatization and occur in different systems of the human organism. The gas exchange under these conditions of extreme hypoxia has been studied by many scientific expeditions. Especially the American Medical Research Expedition to Everest in October 1981 lead by Prof. West gave us much better understanding of high altitude physiology. The arterial blood gas values in a man without use of supplementary O2 on the summit have been estimated in average to be pH = 7.76, pCO2 = 1.0 kPa, pO2 = 3.9 kPa. The barometric pressure, alveolar/end capillary pO2 difference, diffusing capacity for O2, alveolar ventilation, cardiac output, p50 and transit time of the erythrocytes in the lungs are among the most important factors to understand how it is possible to climb Everest without supplementary oxygen.

Acclimatization↗
PubMed2005

Impacts of cold climate on human heat balance, performance and health in circumpolar areas.

In circumpolar areas the climate remains cool or thermoneutral during the majority of the days of the year spite of global warming. Therefore, health consequences related to cold exposure represent also in the future the majority of climate-related adverse health effects. Hot summers may be an exception. At ambient temperatures below +10 - +12 degrees C, humans experience cold stress of varying degree. Man can compensate a 10 degrees C change in ambient temperature by changing metabolic heat production by 30-40 W m(-2) or by wearing an additional/taking off ca. 0.4 clo units (corresponding to one thick clothing layer). Cold ambient temperature may be a risk for human health and cause varying levels of performance limitations. The impacts of cold exposure on health and wellbeing cause a burden to many societies in terms of lowered productivity and higher costs related to health care systems as well as public health planning and management. In order to provide preventive and protective public health actions for cold-induced adverse health effects, it is important to recognize cold related injuries, illnesses and symptoms and their turn-up temperatures, and to identify the most at-risk population subgroups and factors that increase or decrease the health risks posed by cold ambient temperatures. The majority of cold-related harmful health impacts can be prevented or managed by correct preventive and protective actions. Rapid unpredictable changes are more difficult to compensate because of lack of experience (affecting attitude and skills), preparedness (vehicles, garments, supplies, logistics etc.) and/or acclimatization.

Acclimatization↗
PubMed1986

Heat stress: a threat to health and safety.

This review offers a rational basis for the use of fundamental physiological controlling mechanisms in setting safe environmental limits for occupational situations where heat stress is encountered. There is no single index of heat stress that has been universally accepted. However, the use of wet bulb glove temperature (WBGT) has been adopted by various organizations on occupational health and safety in several industrial countries. Thermal limits suggested for everyday work continue to be subject to argument. The controversies arise from the fact that many factors such as individual variations, acclimatization, clothing, age, sex, physical fitness and work load lead to significant effects on tolerance of man to heat. Several measures for prevention of heat stress under industrial situations are summarized briefly. There is no agreement on a single measure to be used, rather a combination of these measures can be the most effective mean to alleviate or prevent severe heat stress. It is to be hoped that this review may help public health officials and medical doctors of various work occupations resolve some of the problems that arise in setting thermal limits and preventive measures, thus contributing to increase productivity and efficiency of work.

Acclimatization↗
PubMed1999

[Health assessments of a military company stationed on the Maroni River in French Guiana].

Over a 5 month period (October 1996 to February 1997), a rotating company of 146 servicemen belonging to the Navy Airborne 6th Regiment were assigned along the Maroni River in French Guyana. During this mission, the medical personnel treated 387 local residents. Etiologies comprised 51 malaria attacks including 46 involving Plasmodium falciparum and 4 rattlesnake envenomations. The most common cause of consultation by military personnel was mycotic and staphylococcal skin infections, but 5 cases involving poor acclimatization were treated during the hot and dry season. Seven malaria attacks involving Plasmodium falciparum including 2 that were severe occurred despite prophylaxis using chloroquine-proguanil. Treatment with halofantrine was successful in all but one case which required combined chemotherapy using quinine and doxycycline. Five cases of cutaneous leishmaniasis were observed in subjects involved in jungle training. No case of HIV infection was detected upon returning home since most personnel either followed the recommendation to abstain from sex (51 p. 100) or used a condom (90 p. 100 of personnel who had sexual relations). These data illustrate the health risks for mainland French nationals in the region of the Maroni River and underline the need for preventive measures and education.

Acclimatization↗
PubMed1999

Operation Everest III (COMEX '97). Effects of prolonged and progressive hypoxia on humans during a simulated ascent to 8,848 M in a hypobaric chamber.

Exposure to high altitude induces physiological or pathological modifications that are not always clearly attributable to a specific environmental factor: hypoxia, cold, stress, inadequate food. The principal goal of hypobaric chamber studies is to determine the specific effect of hypoxia. Eight male volunteers ("altinauts"), aged 23 to 37 were selected. They were first preacclimatized in the Observatoire Vallot (4,350 m) before entering the chamber. The chamber was progressively decompressed down to 253 mmHg barometric pressure, with a recovery period of 3 days at 5,000 m in the middle of the decompression period. They spent a total of 31 days in the chamber. Eighteen protocols were organized by 14 European teams, exploring the limiting factors of physical and psychological performance, and the pathophysiology of acute mountain sickness (AMS). All subjects reached 8,000 m and 7 of them reached the simulated altitude of 8,848 m. Three altinauts complained of transient neurological symptoms which resolved rapidly with reoxygenation. Body weight decreased by 5.4 kg through a negative caloric balance. Only four days after the return to sea-level, subjects had recovered 3.4 kg, i.e. 63% of the total loss. At 8,848 m (n = 5), PaO2 was 30.6 +/- 1.4 mmHg, PCO2 11.9 +/- 1.4 mmHg, pH 7.58 +/- 0.02 (arterialized capillary blood). Hemoglobin concentration increased from 14.8 +/- 1.4 to 18.4 +/- 1.5 g/dl at 8,000 m and recovered within 4 days at sea-level. AMS score increased rapidly at 6,000 m and was maximal at 7,000 m, especially for sleep. AMS was related to alteration in color vision and elevation of body temperature. VO2MAX decreased by 59% at 7,000 m. The purpose of this paper is to give a general description of the study and the time course of the main clinical and physiological parameters. The altinauts reached the "summit" (for some of them three consecutive times) in better physiological conditions than it would have been possible in the mountains, probably because acclimatization and other environmental factors such as cold and nutrition were controlled.

Acclimatization↗
PubMed2000

Effects of mountaineering training at high altitude (4,350 m) on physical work performance of women.

BACKGROUND: Little is known about work performance of women in hypobaric hypoxia. Moreover, whether native women of moderate altitude (2,000-2,100 m) differ from their lowland counterparts in their ability to adjust to hypobaric hypoxia is also not known. Hence, physiological alterations on work performance due to mountaineering training with altitude adaptation was evaluated in two groups of women and compared to the differences in the responses of the native women of moderate altitudes (Highlanders-HL) with those of the plains (Lowlanders-LL). METHODS: Pre-training tests were conducted at 2,100 m, then during sojourn to 4,350 m and re-tested again after return to 2,100 m. Physical work performance was assessed following standard step-test-exercise on a 30 cm stool with 24 cycles x min(-1) for 5 min. Heart rate, BP, ventilation, oxygen consumption and oxygen saturation were monitored at rest and during exercise followed by 5 min recovery in all three situations. RESULTS: During initial assessment, HL showed higher cardiovascular efficiency with faster recovery of exercise heart rate. Both groups showed significant improvement in physical performance due to mountaineering training at high altitude (HA). The difference in performance between two groups narrowed down at 4,350 m and further reduced during re-test with maintenance of initial superiority of the HL. CONCLUSIONS: a) Native women of moderate altitude (HL) are more fit compared with their plains counterparts (LL); b) All women achieved marked improvement in cardiovascular and respiratory efficiency as well as the step-test score due to intense mountaineering training at HA, and the rate of improvement in physical performance was higher in LL; c) Further, induction by trekking under progressive hypoxia coupled with rigorous mountaineering activity at HA merits in understanding better acclimatization and improved physical performance.

Acclimatization↗
PubMed1975

Influence of low ambient temperature and dietary lipids on adipose tissue and plasma fatty acid composition of the Japanese quail.

Japanese quail were maintained on synthetic diets containing 15% corn oil, 15% tallow, and zero fat, and were later exposed at 3.5 degrees C for 21 days. A distinct influence of dietary fat composition upon the adipose tissue triglyceride fatty acid composition was detected, but no change in fatty acid composition was produced with cold exposure. The fatty acid composition of adipose tissue from quail acclimatized to winter temperatures showed no trend towards a greater degree of unsaturation. There was no evidence of a gross selective mobilization of certain fatty acids from the depot lipids. Regional variation in the fatty acid composition of avian fats is discussed with respect to the level of food intake and body temperature.

Acclimatization↗
PubMed2002

Speech motor control and acute mountain sickness.

BACKGROUND: An objective method that accurately quantifies the severity of Acute Mountain Sickness (AMS) symptoms is needed to enable more reliable evaluation of altitude acclimatization and testing of potentially beneficial interventions. HYPOTHESIS: Changes in human articulation, as quantified by timed variations in acoustic waveforms of specific spoken words (voice onset time; VOT), are correlated with the severity of AMS. METHODS: Fifteen volunteers were exposed to a simulated altitude of 4300 m (446 mm Hg) in a hypobaric chamber for 48 h. Speech motor control was determined from digitally recorded and analyzed timing patterns of 30 different monosyllabic words characterized as voiced and unvoiced, and as labial, alveolar, or velar. The Environmental Symptoms Questionnaire (ESQ) was used to assess AMS. RESULTS: Significant AMS symptoms occurred after 4 h, peaked at 16 h, and returned toward baseline after 48 h. Labial VOTs were shorter after 4 and 39 h of exposure; velar VOTs were altered only after 4 h; and there were no changes in alveolar VOTs. The duration of vowel sounds was increased after 4 h of exposure and returned to normal thereafter. Only 1 of 15 subjects did not increase vowel time after 4 h of exposure. The 39-h labial (p = 0.009) and velar (p = 0.037) voiced-unvoiced timed separations consonants and the symptoms of AMS were significantly correlated. CONCLUSIONS: Two objective measures of speech production were affected by exposure to 4300 m altitude and correlated with AMS severity. Alterations in speech production may represent an objective measure of AMS and central vulnerability to hypoxia.

Acclimatization↗
PubMedDate not supplied

In vitro micropropagation of Lawsonia inermis (Lythraceae).

A successful protocol was developed for mass propagation of Lawsonia inermis Linn., an important medicinal plant. Multiple shoots were induced in apical and axillary meristems derived from mature explants of L. inermis on Murashige and Skoog (1962) medium supplemented with 0.25 mg/l 6-benzylaminopurine (BA), 0.25 mg/l Kinetin (Kn), 0.5 mg/l ascorbic acid and 3% (w/v) sucrose. The rate of multiplication was higher when the cultures were incubated under continuous light rather than the 14 hr photoperiod. Rooting was readily achieved upon transferring the microshoots onto MS basal semi-solid medium supplemented with 0.25 mg/l indole-3-butyric acid (IBA) after ten days of culture. Micropropagated plantlets were acclimatized and successfully grown in soil.

Acclimatization↗
PubMed2003

[Toleration of high altitudes by patients with heart and pulmonary diseases].

The decisive limiting parameter in such patients is the lower oxygen partial pressure in inhaled air. It is, however, still possible for patients with coronary heart disease, high blood pressure or bronchial asthma to tolerate high altitudes without having to experience health problems. Prerequisites, however, are adequate acclimatization, optimal medication and pre-travel stable status. In addition, patients must be informed about emergency measures and how to recognize high-altitude sickness. To prevent pneumothorax leading to rapid decompression during flights, particular attention must be addressed to the problem of trapped air in patients with emphysema or cystic fibrosis.

Acclimatization↗
PubMed2003

Blood gases, hematology, and renal blood flow during prolonged mountain sojourns at 3500 and 5800 m.

BACKGROUND: This study mainly focused on renal blood flow, hematological parameters, blood gases, and blood pH, which are affected on exposure to moderate (3500 m) and extreme altitudes (5800 m) in sea level residents. HYPOTHESIS: Acute and prolonged exposure to high or extreme altitude may cause pathophysiological changes in kidney and renal plasma/blood flow, leading to retention of fluids in the tissues. Combined with the decreased availability of oxygen to the tissues, these may be responsible for high altitude maladies. METHOD: Fifteen male sea level (SL) volunteers, 22-25 yr old, were studied for blood gases, blood viscosity, hematocrit, hemoglobin concentration, and effective renal blood/plasma flow at Delhi (260 m), 3500 m (60 d stay), 5800 m (70 d stay), and 7 d after return to SL. RESULTS: Compared with SL, a significant increase from 7.34 to 7.43 (p < 0.01) in blood pH was observed at 3500 m that remained significantly increased at 5800 m. PO2 was about 39% less at 5800 m than at SL. PCO2 reduced significantly from 42.07 to 28.05 mm Hg on return from 5800 m to SL. The blood viscosity increased significantly (38%) at 5800 m and decreased significantly by 38% (p < 0.01) after return to SL. The effective renal plasma flow reduced significantly (p < 0.01) from 615.6 at SL to 381.5 ml x min(-1) x 1.73 m(-2) at 5800 m. CONCLUSION: The study suggests a crucial role of renal function in the acclimatization process; renal function also appears to be one factor by which the body protects itself against severe hypoxia.

Acclimatization↗
PubMed2003

Micropropagation of Glandularia perakii Cov. et Schn. (Verbenaceae), a native species with ornamental potential.

Glandularia perakii is a perennial species with beautiful violet flowers that grows in the stony soil of Mendocine pedemont. A plentiful and prolonged flowering confers it an important ornamental potential. In this paper, a method of propagation of G. perakii from nodal segments is reported. Proliferating microshoot cultures were obtained by placing nodal segment on Murashige and Skoog medium (MS) supplemented with 20 g.L-1 of sucrose without growth regulators. In this medium multiplication rate after 20 days was 7.9. Rooted plants were acclimatized successfully.

Acclimatization↗
PubMedDate not supplied

[Clinical course of a radiation lesion under high-mountain conditions].

The development and outcome of radiation disease were studied on dogs kept at an altitude of 3200 m above sea level. Clinical observations, morphological examinations of blood and bone marrow and measurements of blood coagulation parameters were carried out at different time intervals. Our findings demonstrated that irradiation of animals that followed a 25-day altitude acclimatization and their subsequent exposure to an altitude alleviated radiation disease. The clinical course of radiation disease aggravated in dogs that were reacclimatized to highlands after irradiation. It can be postulated that the dogs kept in highlands before and after irradiation developed a more intensive process of restoration, especially of erythropoiesis. They also showed a stable decrease of the blood coagulation rate and long persistence of high fibrinolytic activity of the blood.

Acclimatization↗
PubMed1992

Hematological parameters are altered during cold air exposure.

Whole blood hematocrit (HCT) decreases during multiple exposures to cold air. To better understand this finding, we have analyzed hematological profiles in 27 normal adult men exposed repeatedly to cold air in one of two experimental protocols. Experiment I was a cold air acclimatization study (CAA) conducted with two groups of 8 men in each group before, during, and after 80 separate 30-minute cold (4 degrees C) air exposures. As part of a metabolic study, half of the men received placebo daily (n = 8), and the other half received an oral daily maintenance dose of the thyroid hormone triiodothyronine (T3) (30 micrograms/day). Blood was analyzed prior to and after every 20 cold exposures. Both groups reacted similarly. When compared with basal conditions, hematocrit (HCT) and erythrocyte counts (RBC) were decreased (p less than 0.05); mean corpuscular hemoglobin concentration (MCHC) and plasma volume (PV) were increased with cold exposure (p less than 0.05). Hemoglobin (Hb), leukocyte counts (WBC), and mean corpuscular volume (MCV) were unchanged. Experiment II was carried out with 9 military volunteers during extended arctic winter field operations (EAO) in Utah and Alaska. Blood was analyzed prior to and after completion of EAO. A changing hematological profile similar to that in the CAA protocol was found. Hematocrit and RBC were decreased (p less than 0.02); MCHC and PV were increased (p less than 0.02). Hemoglobin, WBC, and MCV were unchanged. In addition, there was a negative correlation between HCT and the absolute reticulocyte count in this second experiment. It would appear that in instances of cold stress, whether induced or naturally occurring, certain blood cellular elements respond in a similar adaptive manner.

Acclimatization↗
PubMed2004

Pulmonary artery pressure in Ladakhi men on exposure to acute hypoxia after a stay at sea level.

We had observed that very few Ladakhi soldiers (native highlanders: NHL) are hospitalized for high altitude pulmonary oedema. We hypothesized that this may happen because pulmonary artery pressures of NHLs do not increase even after exposure to acute hypoxia. The aim of this study was to test the above hypothesis by non-invasive echocardiographic assessment of pulmonary arterial pressure in freshly inducted Ladakhi soldiers and comparing it with that in freshly inducted lowlander soldiers (LL). The pre-ejection period and acceleration time ratio as measured from the pulmonary artery Doppler signal was used to compute mean pulmonary arterial pressure. In NHL this pressure on day 1 of induction was significantly lower at 25.8 +/- 6.5 mmHg as compared to 31.9 +/- 9.5 mmHg in LL (P = 0.0002). Another finding of interest was the very low Lake Louise acute mountain sickness score in the NHL (0.278 +/- 0.461 on day 2). This appears to be further evidence that the natives of Ladakh are adapted to hypoxia and not merely acclimatized.

Acclimatization↗
PubMed2005

Temperature related seasonal changes in Golgi complex of brain, heart and intestine of a teleost.

Impact of temperature related seasonal changes in density of Golgi complex were studied in brain, heart and intestine of the freshwater catfish, Clarias batrachus (Linnaeus). The density of Golgi complex was more in these organs of the fish acclimatized to a lower temperature (20 degrees C) than that to a higher temperature (29 degrees C). This suggests that lower temperature induces secretory activity in cells to cope up with the changes in surrounding environment. It could be a kind of histophysiological adaptation in poikilothermic animal.

Acclimatization↗
PubMed2005

[Hazards of mountain climbing and hiking].

At elevations above 1500 m, even a healthy person undergoes acclimatization. To avoid problems such as acute mountain sickness (AMS), high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE), the speed of ascent and the daily sleeping elevation are of primary importance. Mild symptoms and peripheral swelling are usually harmless. However, when the severity of altitude sickness progresses, rapid therapy and immediate transport to lower elevations can be life-saving under certain conditions. A sojourn in the mountains requires effective preparation and prophylaxis against oxygen deficiency, increased UV radiation, as well as against the possibility of hypothermia and frostbite.

Acclimatization↗