Intestinal carbohydrate absorption and permeability at high altitude (5,730 m)

1994 ◽  
Vol 76 (5) ◽  
pp. 1903-1907 ◽  
Author(s):  
A. J. Dinmore ◽  
J. S. Edwards ◽  
I. S. Menzies ◽  
S. P. Travis
Keyword(s):  
Body Weight ◽  
High Altitude ◽  
Sea Level ◽  
Intestinal Permeability ◽  
Intestinal Function ◽  
Carbohydrate Absorption ◽  
Dietary Records ◽  
The Uk ◽  
Glucose Excretion ◽  
Paired T Test

To investigate the effects of high altitude on intestinal function, the absorption and permeation of nonmetabolizable carbohydrates were measured in 14 volunteers (median age 21 yr, range 19–37 yr) at sea level in Oxford, UK; at 1,050 m in Nepal; at 5,570 m after 5 days at > 5,500 m; and at 5,730 m after 11 days at > 5,500 m. Body weight decreased 5.7 +/- 1.19 kg from sea level to 5,570 m (P < 0.001 by paired t test) despite 72-h dietary records showing no change in energy intake. Absorption of carbohydrates by mediated transport was measured by urinary xylose and 3-O-methyl-D-glucose excretion. Xylose excretion (%oral dose) decreased from 31.4 +/- 4.5% to 20.7 +/- 4.5% (P < 0.001) and 3-O-methyl-D-glucose excretion decreased from 39.7 +/- 6.1 to 33.7 +/- 7.0% (P = 0.003) from sea level to 5,730 m. Monosaccharide permeation measured by L-rhamnose excretion decreased from 11.3 +/- 2.5 to 6.2 +/- 2.0% (P = 0.001). Intestinal permeability, a measure of barrier function (ratio of lactulose to L-rhamnose), increased from 0.036 +/- 0.014 at sea level to 0.084 +/- 0.042 at 1,050 m (P = 0.006), possibly due to infective enteropathy after arrival in Nepal, but reverted to normal (0.045 +/- 0.013; P = 0.062) at 5,730 m. Absorption of all carbohydrates returned to normal after return to the UK. This study showed that a decrease in mediated (D-xylose or 3-O-methyl-D-glucose) and diffusional (L-rhamnose) monosaccharide absorption occurs at high altitude but that intestinal permeability at 5,730 m is unchanged.

Skeletal muscle changes after endurance training at high altitude

1991 ◽  
Vol 71 (6) ◽  
pp. 2114-2121 ◽  
Author(s):  
A. X. Bigard ◽  
A. Brunet ◽  
C. Y. Guezennec ◽  
H. Monod
Keyword(s):  
Skeletal Muscle ◽  
Body Weight ◽  
Lactate Dehydrogenase ◽  
High Altitude ◽  
Endurance Training ◽  
Sea Level ◽  
Dehydrogenase Activity ◽  
Altitude Training ◽  
Lactate Dehydrogenase Activity ◽  
Simulated High Altitude

The effects of endurance training on the skeletal muscle of rats have been studied at sea level and simulated high altitude (4,000 m). Male Wistar rats were randomly assigned to one of four groups: exercise at sea level, exercise at simulated high altitude, sedentary at sea level, and sedentary at high altitude (n = 8 in each group). Training consisted of swimming for 1 h/day in water at 36 degrees C for 14 wk. Training and exposure to a high-altitude environment produced a decrease in body weight (P less than 0.001). There was a significant linear correlation between muscle mass and body weight in the animals of all groups (r = 0.89, P less than 0.001). High-altitude training enhanced the percentage of type IIa fibers in the extensor digitorum longus muscle (EDL, P less than 0.05) and deep portions of the plantaris muscle (dPLA, P less than 0.01). High-altitude training also increased the percentage of type IIab fibers in fast-twitch muscles. These muscles showed marked metabolic adaptations: training increased the activity levels of enzymes involved in the citric acid cycle (citrate synthase, CS) and the beta-oxidation of fatty acids (3 hydroxyacyl CoA dehydrogenase, HAD). This increase occurred mainly at high altitude (36 and 31% for HAD in EDL and PLA muscles; 24 and 31% for CS in EDL and PLA muscles). Training increased the activity of enzymes involved in glucose phosphorylation (hexokinase). High-altitude training decreased lactate dehydrogenase activity. Endurance training performed at high altitude and sea level increased the isozyme 1-to-total lactate dehydrogenase activity ratio to the same extent.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction

2006 ◽  
Vol 290 (6) ◽  
pp. E1078-E1088 ◽  
Author(s):  
Kimberly E. Barnholt ◽  
Andrew R. Hoffman ◽  
Paul B. Rock ◽  
Stephen R. Muza ◽  
Charles S. Fulco ◽  
...  
Keyword(s):  
Body Weight ◽  
High Altitude ◽  
Sea Level ◽  
Caloric Restriction ◽  
Thyroid Stimulating Hormone ◽  
Normal Weight ◽  
Morning Cortisol ◽  
Maintain Body Weight ◽  
Baseline Values ◽  
The Difference

High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

Ventilation in newborn rats after gestation at simulated high altitude

1991 ◽  
Vol 70 (3) ◽  
pp. 1146-1151 ◽  
Author(s):  
R. D. Gleed ◽  
J. P. Mortola
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
High Altitude ◽  
Sea Level ◽  
Body Weight Gain ◽  
Female Rats ◽  
Metabolic Adaptation ◽  
Newborn Rats ◽  
Pregnant Rats

Pregnant rats were kept at a simulated altitude of 4,500 m (PO2 91 Torr) for the whole of gestation and returned to sea level 1 day after giving birth. During pregnancy, body weight gain and food intake were approximately 30% less than in controls at sea level. Measurements were made on the 1-day-old (HYPO) pups after a few hours at sea level. In normoxia, ventilation (VE) measured by flow plethysmography was more (+17%) and O2 consumption (VO2) measured by a manometric method was less (-19%) than in control (CONT) pups; in HYPO pups VE/VO2 was 44% greater than in CONT pups. In acute hyperoxia, VE/VO2 of HYPO and CONT pups decreased by a similar amount (15-20%), indicating some limitation in O2 availability for both groups of pups in normoxia. However, VE/VO2 of HYPO pups, even in hyperoxia, remained above (+34%) that of CONT pups. HYPO pups weighed slightly less than CONT pups, their lungs were hypoplastic, and their hearts were a larger fraction of body weight. An additional group of female rats was acclimatized (8 days) to high altitude before insemination. During pregnancy, body weight gain and food intake of these females were similar to those of pregnant rats at sea level. Measurements on the 1-day-old pups of this group were similar to those of HYPO pups. We conclude that newborn rats born after hypoxic gestation present metabolic adaptation (low VO2) and acclimatization (high VE/VO2), possibly because of hypoxemia. Maternal acclimatization before insemination substantially alters maternal growth in hypoxia but does not affect neonatal outcome.

Body composition at sea level and high altitudes

1961 ◽  
Vol 16 (4) ◽  
pp. 589-592 ◽  
Author(s):  
E. PicÓn-Reátegui ◽  
Rodolfo Lozano ◽  
José Valdivieso
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Body Weight ◽  
High Altitude ◽  
Sea Level ◽  
Total Body Water ◽  
Physical Inactivity ◽  
Caloric Intake ◽  
Extracellular Fluid ◽  
Total Body

Simultaneous determinations of total body water and extracellular fluid, using the antipyrine and sucrose infusion methods, have been carried out in 28 adult male residents at sea level and in 28 residents at an altitude of 14,900 ft. Body composition was calculated from these data. The various body spaces, expressed in percentage of body weight, were similar in the two groups, with the exception of the extracellular fluid which was greater in those in the high altitude group ( P < 0.01). Neither racial characteristics nor altitude appear to be factors generally affecting body composition. In individuals having adequate caloric intake body composition seems to be influenced principally by physical activity. In fact, physical inactivity appeared to produce a loss of active tissue and its replacement by fat. Submitted on November 2, 1960

Increased energy intake minimizes weight loss in men at high altitude

1992 ◽  
Vol 72 (5) ◽  
pp. 1741-1748 ◽  
Author(s):  
G. E. Butterfield ◽  
J. Gates ◽  
S. Fleming ◽  
G. A. Brooks ◽  
J. R. Sutton ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
High Altitude ◽  
Sea Level ◽  
Energy Intake ◽  
Nitrogen Balance ◽  
Volatile Fatty Acids ◽  
Energy Requirement ◽  
Fecal Excretion ◽  
Maintain Body Weight

The hypothesis that high-altitude weight loss can be prevented by increasing energy intake to meet energy requirement was tested in seven men, 23.7 +/- 4.3 (SD) yr, taken to 4,300 m for 21 days. Energy intake required to maintain body weight at sea level was found to be 3,118 +/- 300 kcal/day, as confirmed by nitrogen balance. Basal metabolic rate (BMR), determined by indirect calorimetry, increased 27% on day 2 at altitude and then decreased and reached a plateau at 17% above the sea level BMR by day 10. Energy expended during strenuous activities was 37% lower at altitude than at sea level. Fecal excretion of energy, nitrogen, total fiber, and total volatile fatty acids was not significantly affected by altitude. Energy intake at altitude was adjusted after 1 wk, on the basis of the increased BMR, to 3,452 +/- 452 kcal/day. Mean nitrogen balance at altitude was negative (-0.25 +/- 0.71 g/day) before energy intake was adjusted but rose significantly thereafter (0.20 +/- 0.71 and 0.44 +/- 0.66 g/day during weeks 2 and 3). Mean body weight decreased 2.1 +/- 1.0 kg over the 3 wk of the study, but the rate of weight loss was significantly diminished after the increase in energy intake (201 +/- 75 vs. 72 +/- 48 g/day). Individual regression lines drawn through 7-day segments of body weight showed that in four of seven subjects the slopes of body weight were not significantly different from zero after the 2nd wk. Thus weight loss ceased in four of seven men in whom increased BMR at altitude was compensated with increased energy intake.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Prolonged Sojourn at Very High Altitude Decreases Sea-Level Anaerobic Performance, Anaerobic Threshold, and Fat Mass

2021 ◽  
Vol 12 ◽  
Author(s):  
Robert K. Szymczak ◽  
Tomasz Grzywacz ◽  
Ewa Ziemann ◽  
Magdalena Sawicka ◽  
Radosław Laskowski
Keyword(s):  
Body Weight ◽  
High Altitude ◽  
Sea Level ◽  
Fat Mass ◽  
Anaerobic Threshold ◽  
Aerobic Power ◽  
Hematological Parameters ◽  
Maximal Aerobic Power ◽  
Anaerobic Performance ◽  
Very High

Background: The influence of high altitude on an organism’s physiology depends on the length and the level of hypoxic exposure it experiences. This study aimed to determine the effect of a prolonged sojourn at very high altitudes (above 3,500m) on subsequent sea-level physical performance, body weight, body composition, and hematological parameters.Materials and Methods: Ten alpinists, nine males and one female, with a mean age of 27±4years, participated in the study. All had been on mountaineering expeditions to 7,000m peaks, where they spent 30±1days above 3,500m with their average sojourn at 4,900±60m. Their aerobic and anaerobic performance, body weight, body composition, and hematological parameters were examined at an altitude of 100m within 7days before the expeditions and 7days after they descended below 3,500m.Results: We found a significant (p&lt;0.01) decrease in maximal anaerobic power (MAPWAnT) from 9.9±1.3 to 9.2±1.3W·kg−1, total anaerobic work from 248.1±23.8 to 228.1±20.1J·kg−1, anaerobic threshold from 39.3±8.0 to 27.8±5.6 mlO2·kg−1·min−1, body fat mass from 14.0±3.1 to 11.5±3.3%, and a significant increase (p&lt;0.05) in maximal tidal volume from 3.2 [3.0–3.2] to 3.5 [3.3–3.9] L after their sojourn at very high attitude. We found no significant changes in maximal aerobic power, maximal oxygen uptake, body weight, fat-free mass, total body water, hemoglobin, and hematocrit.Conclusion: A month-long exposure to very high altitude led to impaired sea-level anaerobic performance and anaerobic threshold, increased maximal tidal volume, and depleted body fat mass, but had no effect on maximal aerobic power, maximal oxygen uptake, or hemoglobin and hematocrit levels.

scholarly journals Effect of high altitude on human placental amino acid transport

2020 ◽  
Vol 128 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Owen. R. Vaughan ◽  
Fredrick Thompson ◽  
Ramón. A. Lorca ◽  
Colleen G. Julian ◽  
Theresa L. Powell ◽  
...  
Keyword(s):  
Birth Weight ◽  
Amino Acid ◽  
High Altitude ◽  
Sea Level ◽  
Amino Acid Transport ◽  
Acid Uptake ◽  
Acid Transport ◽  
Transport Capacity ◽  
System A ◽  
Low Altitude

Women residing at high altitudes deliver infants of lower birth weight than at sea level. Birth weight correlates with placental system A-mediated amino acid transport capacity, and severe environmental hypoxia reduces system A activity in isolated trophoblast and the mouse placenta. However, the effect of high altitude on human placental amino acid transport remains unknown. We hypothesized that microvillous membrane (MVM) system A and system L amino acid transporter activity is lower in placentas of women living at high altitude compared with low-altitude controls. Placentas were collected at term from healthy pregnant women residing at high altitude (HA; >2,500 m; n = 14) or low altitude (LA; <1,700 m; n = 14) following planned, unlabored cesarean section. Birth weight, but not placenta weight, was 13% lower in HA pregnancies (2.88 ± 0.11 kg) compared with LA (3.30 ± 0.07 kg, P < 0.01). MVM erythropoietin receptor abundance, determined by immunoblot, was greater in HA than in LA placentas, consistent with lower placental oxygen levels at HA. However, there was no effect of altitude on MVM system A or L activity, determined by Na+-dependent [14C]methylaminoisobutyric acid uptake and [3H]leucine uptake, respectively. MVM abundance of glucose transporters (GLUTs) 1 and 4 and basal membrane GLUT4 were also similar in LA and HA placentas. Low birth weights in the neonates of women residing at high altitude are not a consequence of reduced placental amino acid transport capacity. These observations are in general agreement with studies of IUGR babies at low altitude, in which MVM system A activity is downregulated only in growth-restricted babies with significant compromise. NEW & NOTEWORTHY Babies born at high altitude are smaller than at sea level. Birth weight is dependent on growth in utero and, in turn, placental nutrient transport. We determined amino acid transport capacity in placentas collected from women resident at low and high altitude. Altitude did not affect system A amino acid transport across the syncytiotrophoblast microvillous membrane, suggesting that impaired placental amino acid transport does not contribute to reduced birth weight in this high-altitude population.

Body water metabolism in high altitude natives during and after a stay at sea level

1981 ◽  
Vol 25 (1) ◽  
pp. 47-52 ◽  
Author(s):  
S. C. Jain ◽  
Jaya Bardhan ◽  
Y. V. Swamy ◽  
A. Grover ◽  
H. S. Nayar
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Body Water ◽  
Water Metabolism ◽  
High Altitude Natives

scholarly journals Seasonal and Altitudinal Prevalence of Fascioliasis in Buffalo in Eastern Nepal

2018 ◽  
Vol 4 ◽  
pp. 48-53
Author(s):  
Ramesh Prasad Sah ◽  
Hari Kumar Prasai ◽  
Jiban Shrestha ◽  
Md Hasanuzzaman Talukder ◽  
AKM Anisur Rahman ◽  
...  
Keyword(s):  
High Risk ◽  
High Altitude ◽  
Sea Level ◽  
Rainy Season ◽  
Meat Production ◽  
Parasitic Diseases ◽  
Sedimentation Technique ◽  
Risk Period ◽  
Pasture Contamination ◽  
Low Altitude

Buffalo is the most important livestock commodities for milk, meat production and several other multipurpose uses distributed densely from southern tarai to northern mid-hills in Nepal. Among several internal parasitic diseases fascioliasis is highly economic one caused by Fasciola in buffaloes. However, there are only few studies carried on prevalence of fascioliasis emphasizing buffaloes in relation to seasonal (summer and rainy, and winter) and altitudinal variations. Therefore, we examined prevalence of fascioliasis seasonally and vertically. For the purpose, we selected two districts of eastern Nepal and sampled from low altitude area known as Madhesha ranging from 175-200, Dhankuta from 800-1200 m, and Murtidhunga from 1800-2200 m elevation from the sea level, representing tarai, mid hills and high hills, respectively. Altogether from February 2013 to January 2014 at every two months interval we collected 798 fecal samples from buffaloes; 282 from Murtidhunga, 239 from Dhankuta and 277 from Madhesha. The samples were examined microscopically for the presence of Fasciola eggs using sedimentation technique. Results showed that overall prevalence of fascioliasis in buffaloes was 39.9% (319/798), ranging highest 42.6%in Madhesha followed by 39.7% in Murtidhunga and 37.2% in Dhankuta, respectively. The prevalence of fascioliasis was found to be significantly (p <0.05) high in winter (44.9%) comparing to rainy season (34.4%). The prevalence of fascioliasis in buffaloes was relatively higher in low altitude than high altitude, although it was not statistically significant (p <0.05). In our findings the female buffaloes showed higher prevalence for fascioliasis than in male. Since the fascioliasis in buffaloes is highly endemic, thus strategic deworming in high risk period is recommended along with measure to prevent pasture contamination with buffalo feces.

A STUDY OF VARIOUS INDICES OF ADRENOCORTICAL ACTIVITY DURING 23 DAYS AT HIGH ALTITUDE

1963 ◽  
Vol 26 (4) ◽  
pp. 555-566 ◽  
Author(s):  
P. C. B. MACKINNON ◽  
M. E. MONK-JONES ◽  
K. FOTHERBY
Keyword(s):  
Length Of Stay ◽  
High Altitude ◽  
Sea Level ◽  
Acute Exposure ◽  
Adrenocorticotrophic Hormone ◽  
Adrenocortical Activity

SUMMARY 1. Four men and three women ascended by télépherique and helicopter from 1000 to 4333 m. where they remained for 23 days. 2. Measurements of urinary 17-hydroxycorticosteroids, 17-oxosteroids, pregnanediol and pregnanetriol and circulating eosinophils were made at sea level and at high altitude. 3. An attempt was also made to measure changes in emotional activity by means of the palmar sweat index (PSI). This index was assessed at intervals throughout the day at sea level and at high altitude, and in response to adrenocorticotrophic hormone (ACTH) and a self-imposed stress. 4. Within 24 hr. of acute exposure to high altitude urinary 17-hydroxycorticosteroids increased whilst circulating eosinophils decreased; by the 5th day both were returning to sea-level values. The output of 17-oxosteroids was lower by the 5th day at high altitude and subsequently increased; pregnanediol and pregnanetriol levels remained unchanged. 5. PSIs throughout the day become progressively lower as the length of stay at altitude increased. The response to ACTH at sea level and high altitude appeared to be similar but the response to a self-imposed stress was longer in duration at high altitude than at sea level.

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