High altitude medicine & biology最新文献

Smith, Ben, Nicola Wetherill, and Daniel S. Morris. High-altitude retinopathy presenting as blue spots with prolonged recovery: a case report. High Alt Med Biol. 26:99-101, 2025.-High-altitude retinopathy (HAR) is a common ocular manifestation of high-altitude illness that is usually asymptomatic but can present with reduced or distorted central vision and signs of retinal vascular engorgement and retinal hemorrhages of varying severity. Typically, symptoms are very mild, such as a slight decrease in visual acuity or a small scotoma. There is no treatment for this condition, and most cases resolve spontaneously within 12 weeks without any permanent visual changes. Here we present a case of a previously fit and well 29-year-old female who developed atypical symptoms of "blue spots" in both eyes after ascending to 5,420 m. She descended promptly and was assessed in an emergency ophthalmology clinic in the United Kingdom (UK) upon her return. Her visual recovery was prolonged, which, combined with the presenting symptoms, makes this case atypical and assists in broadening understanding of HAR.

Yu Liu, Zhengyang Zhang, Yongting Luo, Peng An, Jingyi Qi, Xu Zhang, Shuaishuai Zhou, Yongzhi Li, Chong Xu, Junjie Luo, and Jiaping Wang. Product of traditional Chinese medicine longgui yangxinwan protects the human body from altitude sickness damage by reducing oxidative stress and preventing mitochondrial dysfunction. High Alt Med Biol. 26:20-29, 2025. Background: Plateau reaction, caused by high-altitude exposure, results in symptoms like headaches, dyspnea, palpitations, fatigue, shortness of breath, and insomnia due to reduced oxygen levels. Mitochondria are crucial for high-altitude acclimatization as they regulate oxygen metabolism and cellular energy, reducing oxidative stress and maintaining bodily functions. Methods: The study participants were randomly divided into placebo group, Rhodiola group and longgui yangxinwan (Original name: taikong yangxinwan) group, with 20 people in each group. Three groups of subjects were sampled at three time points (PI: pre-intervention; P-D1: high-altitude day 1; P-D7: high-altitude day 7), and blood pressure, blood oxygen, heart rate, hemoglobin, and red blood cell count were measured. The ATP content, mitochondrial DNA copy number, expression of mitochondria-related genes, reactive oxygen species (ROS), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) levels, and mitochondrial morphology were measured in blood at each time point. Results: Our study results demonstrate that longgui yangxinwan keeps the selected human physiological indicators stable and prevents mitochondrial dysfunction in the high altitude. Mechanically, longgui yangxinwan decreases the level of ROS in human serum, whereas increases the activity of the antioxidant enzyme GSH-PX. At high-altitude day 1 (P-D1) and high-altitude day 7 (P-D7), ROS in the placebo group were 1.5 and 2.2-fold higher than those of the longgui yangxinwan group, respectively. In addition, longgui yangxinwan enhances ATP production capacity, restores the levels of mitochondrial respiratory chain complexes, and effectively maintains mitochondrial morphology and integrity. At P-D1 and P-D7, the ATP levels in the longgui yangxinwan group were 19-fold and 26-fold higher than those in the placebo group, respectively. Conclusions: Our study highlights longgui yangxinwan as a potential drug for protecting humans from high-altitude damage by reducing oxidative stress and preventing mitochondrial dysfunction.

Citherlet, Tom, Antoine Raberin, Giorgio Manferdelli, Nicolas Bourdillon, and Grégoire P Millet. Impact of the menstrual cycle on the cardiovascular and ventilatory responses during exercise in normoxia and hypoxia. High Alt Med Biol. 26:55-62, 2025. Introduction: Ovarian hormones influence several physiological functions in women. This study investigated how the hormonal variations across the menstrual cycle (MC) impact cardiovascular and ventilatory responses during rest and moderate exercise in normobaric hypoxia. Methods: Thirteen eumenorrheic women were tested during the early follicular (Fol1), late follicular (Fol2), and mid-luteal (Lut3) phases with measurement of hormonal levels. Heart rate (HR) variability, blood pressure, and baroreflex sensitivity (BRS) were evaluated at rest in normoxia. Ventilation (VE), peripheral oxygen saturation, and HR were monitored at rest and during moderate-intensity cycling exercise in hypoxia (F_iO₂ = 14%). Results: Despite expected hormone level variations, no significant changes were observed across the MC in HR variability (root mean square of successive differences; 64 (95% confidence interval [47, 81]) at Fol1, 54 [42, 66] at Fol2, 60 [44, 77] ms at Lut3), blood pressure (mean blood pressure; 85 [79, 90]), 87 [81, 93]), 84 [77, 92] mmHg), BRS (26 [17, 36], 28 [20, 35], 23 [17, 29] ms/mmHg), VE (rest: 8.9 [7.9, 9.8], 9.5 [9.0, 9.9], 9.0 [8.1, 9.9]; exercise: 53 [41, 66], 51.1 [36.4, 65.7], 54.4 [34.0, 74.8] l/min), peripheral oxygen saturation (rest: 89.8 [87.4, 92.1], 91.9 [88.7, 95.0], 90.2 [87.8, 92.6]; exercise: 80.5 [77.4, 83.5], 84.4 [80.4, 88.3], 81.9 [78.3, 85.4] %) HR (rest: 69.7 [60.2, 79.1], 70.8 [63.2, 78.3], 70.5 [64.0, 77.0]; exercise: 148 [136, 160], 146 [132, 161], 146 [132, 160] bpm), and cycling efficiency (0.17 [0.16, 0.18], 0.17 [0.13, 0.21], 0.16 [0.15, 0.18] %) (all p > 0.05). Discussion: From a practical point of view, there is no strong evidence of any usefulness of monitoring hormonal variations and the MC phases for women exercising in hypoxia.

Vásquez-Velásquez, Cinthya, Diego Fano-Sizgorich, and Gustavo F. Gonzales. Death risk response of high-altitude resident populations to COVID-19 vaccine: a retrospective cohort study. High Alt Med Biol. 26:37-44, 2025. Background: Peru had one of the highest mortality rates caused by the coronavirus disease 2019 (COVID-19) pandemic worldwide. Vaccination significantly reduces mortality. However, the effectiveness of vaccination might differ at different altitudinal levels. The study aimed to evaluate the effect modification of altitude on the association between vaccination and COVID-19 mortality in Peru. Methodology: A retrospective cohort, using open access databases of deaths, COVID-19 cases, hospitalizations, and vaccination was obtained from the Peruvian Ministry of Health. Deaths due to COVID-19 were evaluated in vaccinated and nonvaccinated patients. Crude (RR) and adjusted relative risks (aRR) were calculated using generalized linear models of Poisson family with robust variances. Models were adjusted for age, sex, pandemic wave, and Human Development Index. To evaluate the interaction by altitude, a stratified analysis by this variable was performed. The variable altitude was categorized as, 0-499 m (828,298 cases), 500-1,499 m (64,735 cases), 1,500-2,499 m (106,572 cases), and ≥2,500 m (179,004 cases). The final sample studied included 1,362,350 cases. Results: The vaccine showed a considerable reduction of death risk with the second (aRR: 0.41, 95% confidence interval [CI]: 0.38-0.44) and third doses (aRR: 0.21, 95% CI: 0.20-0.23). In the adjusted and interaction model, it can be observed that medium and high altitude present a higher risk of death compared to sea level (aRR: 2.58 and 2.03, respectively). Likewise, the two doses' group presents an aRR:1.22 for medium altitude (1,500-2,499 m) and 1.6 for high altitude (≥2,500 m), compared with low-altitude population, suggesting that the action of vaccination at high altitude is altered by the effect of the altitude itself. Conclusions: Altitude might modify the protective effect of SARS-CoV-2 vaccine against COVID-19 death.

Horiuchi, Masahiro, and Samuel J. Oliver. Post-exercise hypotension after exercising in hypoxia with and without tart cherry supplementation. High Alt Med Biol. 26:63-69, 2025. Background: This study investigated the effects of hypoxic exercise with and without tart cherry (TC) supplementation on post-exercise hypotension (PEH). Method: In a randomized order, 12 healthy young adults (9 men and 3 women) completed cycle exercise to exhaustion (1) in normoxia without any supplementation (Norm), (2) in hypoxia (13% O₂) with placebo (Hypo), and (3) in hypoxia with TC supplementation (Hypo + TC). Supplements were supplied for 5 days pre-trial (TC was 200 mg anthocyanin per day for 4 days and 100 mg on day 5). Results: Cycle exercise total energy expenditure was greater in Norm than Hypo and Hypo + TC (p < 0.001) with no difference between Hypo and Hypo + TC (p = 0.41). Mean arterial pressure (MAP) decreased during recovery in all trials (main effect of time, p < 0.001), with no difference in PEH between the trials (p > 0.05, change [Δ] in MAP from pre-exercise at 60 minutes recovery, mean difference, Norm Δ-4.4 mmHg, Hypo Δ-6.1 mmHg, and Hypo + TC Δ-5.2 mmHg). Cardiac baroreflex sensitivity decreased during recovery in all trials (p < 0.001) and was lower in Hypo than Norm and Hypo + TC (main effect of trial, p = 0.02). Conclusion: PEH was not increased after exercise in hypoxia, with or without TC supplementation, compared with exercise in normoxia.

Reid, Ly-Anh, Jordan L. Rees, Miranda Kimber, Marina James, Graeme M. Purdy, Megan Smorschok, Lauren E. Maier, Normand G. Boulé, Trevor A. Day, Margie H. Davenport, and Craig D. Steinback. Blood glucose during high altitude trekking in young healthy adults. High Alt Med Biol. 26:30-36, 2025. Introduction: High altitude trekking is becoming more popular and accessible to an increased number of people. Simultaneously, there is a worldwide rise in the prevalence of metabolic diseases. The purpose of this study was to examine the impact of a gradual trekking ascent to high altitude on continuous glucose monitoring outcomes including fasting, mean 24-hour, postprandial, and post-75 g modified oral glucose tolerance test. This study also investigated the relationship between physical activity intensity, high altitude, and glucose concentrations. Methods: Individuals (n = 9) from Alberta, Canada participated in a 2-week trek in the Khumbu Valley in Nepal, ascending by foot from 2,860 m to 5,300 m (∼65 km) over 10 days. A standardized 75 g oral glucose load was given to participants at four different altitudes (1,130 m, 3,440 m, 3,820 m, 5,160 m). Physical activity (Actigraph accelerometry) and interstitial glucose (iPro2, Medtronic) were measured continuously during the trek. Results: Fasting and mean 24-hour glucose concentrations were not different between altitudes. However, 2-hour post dinner glucose and 2-hour post lunch glucose, AUC concentrations were different between altitudes. The relationship between physical activity intensity and glucose was not influenced by increasing altitudes. Conclusion: Our findings suggest that glucose regulation is largely preserved at high altitude; however, inconsistency in our postprandial glucose concentrations at altitude warrants further investigation.