Altitude exposure as a training & iron overload management strategy post leukemia

ObjectivesTo examine iron stores, hemoglobin mass, and performance before, during and after intermittent altitude exposure in a professional male rugby player experiencing iron overload following blood transfusions for treatment for acute myeloid leukemia.DesignLongitudinal, repeated measures, single case-study.MethodsThe player was followed prior to (control), and during (study), an in-season block of altitude training. During the control period two venesections were performed for a total of 750 mL of blood removal. Internal and external training load, match statistics, blood volume, plasma volume, haemoglobin mass, serum ferritin and reticulocyte count were monitored throughout.ResultsDuring the control period serum ferritin declined following the two venesections (∼51%) as did haemoglobin mass (∼2%), reticulocyte count remained stable. During the study period serum ferritin further declined (∼30%), however haemoglobin mass and reticulocyte count increased (∼4% and ∼14% respectively). Internal training load for the control and study period was similar, however external training load was lower in the study period. Match statistics were not favourable for the player during the control period, however they improved during the study period.ConclusionsThis case supports the theory that individuals with elevated iron availability are well placed to achieve increases in haemoglobin mass. Furthermore, although therapeutic venesections may still be required to manage iron overload, the addition of altitude exposure may be a method to assist in reducing total body iron by means of mobilising available (excessive) iron to incorporate into haemoglobin. Altitude exposure did not hinder the players’ performance. Further research is encouraged.     

Subdural Hematoma Associated with High Altitude

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Maximal oxygen uptake and erythropoietic responses after training at moderate altitude

Summary Six well-trained male cross-country skiers trained for 7 days at 2700 m above sea level, their accommodation being at 1695 m. Blood samples for haemoglobin concentration [Hb], erythropoietin concentration [EPO] and reticulocyte count were collected before, during and after altitude exposure. Packed cell volume (PCV), red blood cell count (RBC), transferrin-iron saturation, mean red cell volume (MCV), mean corpuscular haemoglobin concentration (MCHC), maximal oxygen uptake, maximal achieved ventilation and heart rate were determined pre- and postaltitude exposure. The [EPO] increased significantly from prealtitude (mean 36 mU·ml^–1, SD 5) to maximal altitude values (mean 47 mU·ml^–1, SD 3). The [Hb] had increased significantly above pre-altitude values (mean 8.8 mmol·l^–1, SD 0.5) on day 2 (mean 9.1 mmol·l^–1, SD 0.4) and day 7 (mean 9.4 mmol·l^–1, SD 0.4) at altitude and on day 4 postaltitude (mean 9.2 mmol·l^–1, SD 0.4). The reticulocyte counts had increased significantly above pre-altitude values (mean 6, SD 3) on day 3 at altitude (mean 12, SD 8) and day 4 postaltitude (mean 10, SD 5). The RBC counts had increased on the 4th postaltitude day. The transferrin-iron saturation had decreased below pre-altitude values (mean 23%, SD 4%) on day 4 postaltitude (mean 14%, SD 5%) and had increased on day 11 postaltitude (mean 22%, SD 7%). There were no significant changes in MCV, MCHC, PCV, maximal oxygen uptake and maximal achieved ventilation, and heart rate pre- to postaltitude. These observations demonstrated an erythropoietic response to the altitude training which was not sufficient to increase the postaltitude maximal oxygen uptake.     

Metabolic consequences of reduced frequency breathing during submaximal exercise at moderate altitude

Summary The intention of this study was to determine the metabolic consequences of reduced frequency breathing (RFB) at total lung capacity (TLC) in competitive cyclists during submaximal exercise at moderate altitude (1520 m; barometric pressure, P _B=84.6 kPa; 635 mm Hg). Nine trained males performed an RFB exercise test (10 breaths · min ^–1) and a normal breathing exercise test at 75–85% of the ventilatory threshold intensity for 6 min on separate days. RFB exercise induced significant (P<0.05) decreases in ventilation (V _E), carbon dioxide production (VCO₂), respiratory exchange ratio. (RER), ventilatory equivalent for O₂ consumption (V _E/VO₂), arterial O₂ saturation and increases in heart rate and venous lactate concentration, while maintaining a similar OZ consumption (VO₂). During recovery from RFB exercise (spontaneous breathing) a significant (P< 0.05) decrease in blood pH was detected along with increases in V _E, VO₂, VCO₂, RER, and venous partial pressure of carbon dioxide. The results indicate that voluntary hypoventilation at TLC, during submaximal cycling exercise at moderate altitude, elicits systemic hypercapnia, arterial hypoxemia, tissue hypoxia and acidosis. These data suggest that RFB exercise at moderate altitude causes an increase in energy production from glycolytic pathways above that which occurs with normal breathing.     

Resting values of left ventricular work to coronary blood flow ratio in rats exposed to intermittent high altitude hypoxia and swimming

Summary Total hemodynamic values and left ventricular blood flow were studied using Sapirstein's method of ⁸⁶Rb uptake in female rats 24 h after a last exposure to high altitude. A simulated altitude of 1350 m was used, initial exposure being for 30 min, gradually increased by 30 min daily up to 330 min daily for 5 days a week; the total number of exposures was 32. In another animal group the hypobaric exposure was combined with swimming in water at 37 C.In both experimental groups the cardiac output and stroke volume increased, and in rats undergoing swimming the total peripheral resistance decreased as well.In the rats exposed to intermittent hypoxia only, left ventricular blood flow increased by about the same proportion as the cardiac output. The ratio of left ventricular work to coronary blood flow was significantly increased.In rats exposed to the combined influence of hypoxia and swimming, the increase in left ventricular blood flow did not match either the increase in cardiac output, or the weight gain of the left ventricle. The ventricular work to coronary blod flow ratio was the same as in controls.     

Alp and valley cattle: Exercise in cold,hot and high environments

Summary Two groups of cattle, one kept on an alpine pasture (1700–2600 m altitude) for 5 summer months and the kept in a barn at 400 m, were subjected to treadmill exercise for 15 min at a speed of 2 km/h in environments of 15°C, –10°C, 35°C (all at 400 m) and at simulated altitude of 3500 m (at 15° C). In the resting conditions, the alpine cattle had higher respiration rates and body temperatures at an air temperature of 35°C than the valley cattle which was atributed to a greater hair insulation and possibly a low responsiveness of the sweat glands. At 3500 m, the alpine animals had higher resting heart rates than the valley animals, which was attributed to a greater blood volume. After exercise, heart rates in the alpine cattle were from 10–19 beats/min lower than in the valley cattle, due to exercise conditioning in the former animals. This training effect on heart rates in the alpine animals was paralleled by reduction in intrinsic heart rates (using atropine and propranolol as blocking agents). Atropine blockade also indicated that exercise-trained cattle have a lower vagus tone compared to non-exercise-trained cattle.     

高原低氧对血脑屏障结构及其药物通透性影响的研究进展

中枢神经系统疾病治疗药物需通过血脑屏障进入脑组织发挥作用。在高原低氧环境下,血脑屏障组织结构中的紧密连接蛋白、星型胶质细胞和内皮细胞上的转运蛋白、内皮细胞上的ATP发生变化,同时血脑屏障通透性增加。这些变化是高原地区中枢神经系统疾病患者的合理用药的重要参考。本文就高原低氧对血脑屏障结构及其药物通透性影响的研究进展作一综述。     

基于GoPubMed有关高原病研究文献的信息分析

依托PubMed数据库,采用GoPubMed进行检索,从研究内容、发文作者、地区分布、发文时间等方面分析有关高原病的研究文献,获得高原病研究的主题内容、年代、地区分布、期刊、核心作者等信息,并利用结构方程模型对高原病研究文献量的影响因素进行分析,探索与高原病研究的相关趋势,最后提出了借鉴印度德里的经验,将我国相对分散的高原病研究资源进行适当集中,加强国内外科研人员的相互协作,加大高原医学研究的支持力度,在进行大规模非战争军事行动（如救灾）时应结合我国高原、高山地貌比例高、高原人口较多、地质灾害多发等特点,将我国的高原病救治机构适当向高原腹地前移等建议。