scholarly journals Prediction of High-Altitude Cardiorespiratory Fitness Impairment Using a Combination of Physiological Parameters During Exercise at Sea Level and Genetic Information in an Integrated Risk Model

2022 ◽  
Vol 8 ◽  
Author(s):  
Jie Yang ◽  
Hu Tan ◽  
Mengjia Sun ◽  
Renzheng Chen ◽  
Jihang Zhang ◽  
...  

Insufficient cardiorespiratory compensation is closely associated with acute hypoxic symptoms and high-altitude (HA) cardiovascular events. To avoid such adverse events, predicting HA cardiorespiratory fitness impairment (HA-CRFi) is clinically important. However, to date, there is insufficient information regarding the prediction of HA-CRFi. In this study, we aimed to formulate a protocol to predict individuals at risk of HA-CRFi. We recruited 246 volunteers who were transported to Lhasa (HA, 3,700 m) from Chengdu (the sea level [SL], <500 m) through an airplane. Physiological parameters at rest and during post-submaximal exercise, as well as cardiorespiratory fitness at HA and SL, were measured. Logistic regression and receiver operating characteristic (ROC) curve analyses were employed to predict HA-CRFi. We analyzed 66 pulmonary vascular function and hypoxia-inducible factor- (HIF-) related polymorphisms associated with HA-CRFi. To increase the prediction accuracy, we used a combination model including physiological parameters and genetic information to predict HA-CRFi. The oxygen saturation (SpO2) of post-submaximal exercise at SL and EPAS1 rs13419896-A and EGLN1 rs508618-G variants were associated with HA-CRFi (SpO2, area under the curve (AUC) = 0.736, cutoff = 95.5%, p < 0.001; EPAS1 A and EGLN1 G, odds ratio [OR] = 12.02, 95% CI = 4.84–29.85, p < 0.001). A combination model including the two risk factors—post-submaximal exercise SpO2 at SL of <95.5% and the presence of EPAS1 rs13419896-A and EGLN1 rs508618-G variants—was significantly more effective and accurate in predicting HA-CRFi (OR = 19.62, 95% CI = 6.42–59.94, p < 0.001). Our study employed a combination of genetic information and the physiological parameters of post-submaximal exercise at SL to predict HA-CRFi. Based on the optimized prediction model, our findings could identify individuals at a high risk of HA-CRFi in an early stage and reduce cardiovascular events.

1974 ◽  
Vol 37 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J Raynaud ◽  
J P Martineaud ◽  
J Bordachar ◽  
M C Tillous ◽  
J Durand

1991 ◽  
Vol 261 (4) ◽  
pp. E419-E424 ◽  
Author(s):  
R. S. Mazzeo ◽  
P. R. Bender ◽  
G. A. Brooks ◽  
G. E. Butterfield ◽  
B. M. Groves ◽  
...  

Exercise at high altitude is a stress that activates the sympathoadrenal systems, which could affect responses to acute altitude exposure and promote adaptations during chronic altitude exposure. However, catecholamine levels are not clearly described over time at high altitude. In seven male volunteers (23 yr, 72 kg), resting arterial norepinephrine concentrations (ng/ml) on arrival at Pikes Peak (0.338 +/- 0.041) decreased compared with sea-level values (0.525 +/- 0.034) but increased to above sea-level values after 21 days at 4,300 m (0.798 +/- 0.052). Furthermore, during 45 min of constant submaximal exercise, values were similar at sea level (1.670 +/- 0.221) and on acute exposure to 4,300 m (2.123 +/- 0.086) but increased after 21 days of chronic exposure (2.693 +/- 0.216). By contrast, resting arterial epinephrine values (ng/ml) during acute and chronic exposure (0.708 +/- 0.033 vs. 0.448 +/- 0.026) both exceeded those of sea level (0.356 +/- 0.020). During exercise values on arrival were greater than at sea level (0.921 +/- 0.024 vs. 0.397 +/- 0.035) but fell to 0.612 +/- 0.025 ng/ml after 21 days. Exercise norepinephrine levels were related to systemic vascular resistance measurements (r = 0.93), whereas epinephrine levels were related to circulating lactate (r = 0.95). We conclude that during exercise at altitude there is a dissociation between norepinephrine, an indicator of sympathetic neural activity, and epinephrine, an indicator of adrenal medullary response. These actions may account for different metabolic and physiological responses to acute vs. chronic altitude exposure.


2021 ◽  
Vol 12 (10) ◽  
pp. 58-63
Author(s):  
Gopinath Bhaumik ◽  
Deepak Dass ◽  
Dishari Ghosh ◽  
Kishan Singh ◽  
Maram Prasanna Kumar Reddy

Background: In emergency like condition, defence personnel are deployed to high altitude without proper acclimatization. Maladaption at high altitude leads to high altitude illness like acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE) which hampers the operational capabilities. Aims and Objectives: The aim of the present study was to assess the effect of intermittent normobaric hypoxia exposure (IHE) at sea level on different physiological responses during initial days of acclimatization at 3500m and 4000m altitudes in acute induction. Materials and Methods: The IHE subjects were exposed to 12% FIO2 (equivalent altitude 14500 ft) for 4 hrs/day for 4 consecutive days at sea level and 5th day they were inducted by air to 3500m altitude. Baseline recording of different physiological parameters like cardiovascular, respiratory, oxygen saturation and AMS score were measured at sea level as well as 3500m altitude on daily basis for 6 days to assess acclimatization status. To confirm acclimatization status at 3500m, on fifth day the IHE group subjects were transported by road to 4000m and again measured different basal physiological parameters (like cardiovascular, oxygen saturation and AMS score) for four consecutive days. Results: Different physiological parameters of IHE treated group were stabilized by day 4 of air induction at 3500m altitude. Whereas, at 4000m altitude, these parameters were stabilized by day 2 of induction. Conclusion: Acclimatization schedules of four days at 3500m and two days at 4000m are essential to avoid malacclimatization/or high-altitude illness.


1995 ◽  
Vol 269 (1) ◽  
pp. R201-R207 ◽  
Author(s):  
R. S. Mazzeo ◽  
G. A. Brooks ◽  
G. E. Butterfield ◽  
D. A. Podolin ◽  
E. E. Wolfel ◽  
...  

This investigation examined the relationship between alterations in plasma norepinephrine associated with 21 days of high-altitude exposure and muscle sympathetic activity both at rest and during exercise. Healthy sea level residents, divided into a control group (n = 5) receiving a placebo or a drug group (n = 6) receiving 240 mg/day of propranolol, were studied while at sea level, upon arrival (acute), and after 21 days of residence (chronic) at 4,300 m. Arterial norepinephrine levels and net leg uptake and release of norepinephrine were determine both at rest and during 45 min of submaximal exercise via samples collected from femoral arterial and venous catheters. Arterial norepinephrine levels increased significantly after chronic altitude exposure both at rest (84%) and during exercise (174%) compared with sea level and acute values. A net uptake of norepinephrine was found in resting legs at sea level (0.28 +/- 0.05 nmol/min) and with acute exposure (0.07 +/- 0.06 nmol/min); however, a significant switch to net leg norepinephrine release was observed with chronic altitude exposure (0.51 +/- 0.11 nmol/min). With exercise, a net release of norepinephrine by the leg occurred across all conditions with chronic exposure, again eliciting the greatest values (5.3 +/- 0.6, 8.0 +/- 1.7, and 14.4 +/- 3.1 nmol/min for sea level, acute, and chronic exposure, respectively). It was concluded that muscle sympathetic activity is significantly elevated both at rest and during submaximal exercise as a result of chronic high-altitude exposure, and muscle is a major contributor to the increase in plasma norepinephrine levels associated with prolonged altitude exposure. The presence of dense beta-blockade did not alter this adaptation to altitude.


2001 ◽  
Vol 19 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Annette Schneider ◽  
Richard E. Greene ◽  
Cornelius Keyl ◽  
Gabriele Bandinelli ◽  
Claudio Passino ◽  
...  

1998 ◽  
Vol 85 (3) ◽  
pp. 1092-1102 ◽  
Author(s):  
Eugene E. Wolfel ◽  
Mark A. Selland ◽  
A. Cymerman ◽  
George A. Brooks ◽  
Gail E. Butterfield ◽  
...  

Whole body O2 uptake (V˙o 2) during maximal and submaximal exercise has been shown to be preserved in the setting of β-adrenergic blockade at high altitude, despite marked reductions in heart rate during exercise. An increase in stroke volume at high altitude has been suggested as the mechanism that preserves systemic O2 delivery (blood flow × arterial O2 content) and thereby maintainsV˙o 2 at sea-level values. To test this hypothesis, we studied the effects of nonselective β-adrenergic blockade on submaximal exercise performance in 11 normal men (26 ± 1 yr) at sea level and on arrival and after 21 days at 4,300 m. Six subjects received propranolol (240 mg/day), and five subjects received placebo. At sea level, during submaximal exercise, cardiac output and O2 delivery were significantly lower in propranolol- than in placebo-treated subjects. Increases in stroke volume and O2 extraction were responsible for the maintenance of V˙o 2. At 4,300 m, β-adrenergic blockade had no significant effect onV˙o 2, ventilation, alveolar Po 2, and arterial blood gases during submaximal exercise. Despite increases in stroke volume, cardiac output and thereby O2 delivery were still reduced in propranolol-treated subjects compared with subjects treated with placebo. Further reductions in already low levels of mixed venous O2 saturation were responsible for the maintenance ofV˙o 2 on arrival and after 21 days at 4,300 m in propranolol-treated subjects. Despite similar workloads and V˙o 2, propranolol-treated subjects exercised at greater perceived intensity than subjects given placebo at 4,300 m. The values for mixed venous O2 saturation during submaximal exercise in propranolol-treated subjects at 4,300 m approached those reported at simulated altitudes >8,000 m. Thus β-adrenergic blockade at 4,300 m results in significant reduction in O2delivery during submaximal exercise due to incomplete compensation by stroke volume for the reduction in exercise heart rate. Total bodyV˙o 2 is maintained at a constant level by an interaction between mixed venous O2 saturation, the arterial O2-carrying capacity, and hemodynamics during exercise with acute and chronic hypoxia.


2020 ◽  
Vol 128 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Owen. R. Vaughan ◽  
Fredrick Thompson ◽  
Ramón. A. Lorca ◽  
Colleen G. Julian ◽  
Theresa L. Powell ◽  
...  

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.


1981 ◽  
Vol 25 (1) ◽  
pp. 47-52 ◽  
Author(s):  
S. C. Jain ◽  
Jaya Bardhan ◽  
Y. V. Swamy ◽  
A. Grover ◽  
H. S. Nayar

2018 ◽  
Vol 4 ◽  
pp. 48-53
Author(s):  
Ramesh Prasad Sah ◽  
Hari Kumar Prasai ◽  
Jiban Shrestha ◽  
Md Hasanuzzaman Talukder ◽  
AKM Anisur Rahman ◽  
...  

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.


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