Rapid Acclimatization Strategies for High-Altitude Induction

Bhaumik, Gopinath; Bansal, Anju; Ghosh, Dishari; Kumar, Harish; Kumar, Sanjeev; Dass, Deepak; Kanujia, Jitendra; Singh, Krishan; Kumar, Utkarsha; Suryakumari, Sarada; Singh, Mrinalini; Saxena, Shweta; Saraswat, Deepika; Majundar, D.; Singh, Shashi Bala

doi:10.1007/978-81-322-1928-6_12

Cited by 3 publications

(1 citation statement)

References 105 publications

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“…Hypoxia preconditioning, either through physical or pharmacological means, is an emerging therapeutic intervention to cope with hypoxia at HA. It triggers the acclimatization responses prior to actual hypoxia exposure and hence improving sustenance at HA . In a pioneering previous study, we have demonstrated that preconditioning with exogenous sphingosine‐1‐phosphate (S1P), a bioactive lipid, in rats prior to acute HH exposure, raises their adaptive responses such as diuresis, RBC count, and hemoglobin content, culminating into raised oxygen saturation (oxygen bioavailability) even under hypoxic environment .…”

Section: Introductionmentioning

confidence: 99%

S1P prophylaxis mitigates acute hypobaric hypoxia‐induced molecular, biochemical, and metabolic disturbances: A preclinical report

2016

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Sphingosine-1-phosphate (S1P) is emerging to have hypoxic preconditioning potential in various preclinical studies. The study aims to evaluate the preclinical preconditioning efficacy of exogenously administered S1P against acute hypobaric hypoxia (HH)-induced pathological disturbances. Male Sprague Dawley rats (200 6 20 g) were preconditioned with 1, 10, and 100 lg/kg body weight (b.w.) S1P (i.v.) for three consecutive days. On the third day, S1P preconditioned animals, along with hypoxia control animals, were exposed to HH equivalent to 7,620 m (280 mm Hg) for 6 h. Postexposure status of cardiac energy production, circulatory vasoactive mediators, pulmonary and cerebral oxidative damage, and inflammation were assessed. HH exposure led to cardiac energy deficit indicated by low ATP levels and pronounced AMPK activation levels, raised circulatory levels of brain natriuretic peptide and endothelin-1 with respect to total nitrate (NOx), redox imbalance, inflammation, and alterations in NOx levels in the pulmonary and cerebral tissues. These pathological precursors have been routinely reported to be coincident with high-altitude diseases. Preconditioning with S1P, especially 1 mg/kg b.w. dose, was seen to reverse the manifestation of these pathological disturbances. The protective efficacy could be attributed, at least in part, to enhanced activity of cardioprotective protein kinase C and activation of small GTPase Rac1, which led to further induction of hypoxia-adaptive molecular mediators: hypoxia-inducible factor (HIF)21a and Hsp70. This is a first such report, to the best of our knowledge, elucidating the mechanism of exogenous S1P-mediated HIF-1a/Hsp70 induction. Conclusively, systemic preconditioning with 1 lg/kg b.w. S1P in rats protects against acute HHinduced pathological disturbances. V C 2016 IUBMB Life, 68(5): [365][366][367][368][369][370][371][372][373][374][375] 2016

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Section: Introductionmentioning

confidence: 99%

S1P prophylaxis mitigates acute hypobaric hypoxia‐induced molecular, biochemical, and metabolic disturbances: A preclinical report

2016

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Rapid ascents of Mt Everest: normobaric hypoxic preacclimatization

Tannheimer

Lechner

2020

Journal of Travel Medicine

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Background Acclimatization to high altitude is time consuming. An expedition to Mt. Everest (8848 m) requires roughly 8 weeks. Therefore it seems very attractive to reach the summit within three weeks from home, which is currently promised by some expedition tour operators. These rapid ascent expeditions are based on two main components, normobaric hypoxic training (NHT) prior to the expedition and the use of high flow supplemental oxygen (HFSO2). We attempted to assess the relative importance of these two elements. Methods We evaluated the effect of NHT on the basis of the available information of these rapid ascent expeditions and our experiences made during an expedition to Manaslu (8163 m) where we used NHT for preacclimatization. To evaluate the effect of an increased O2-flow rate we calculated its effect for different activity levels at altitudes of 8000 m and above. Results So far rapid ascents to Mt. Everest have been successful. The participants carried out 8 weeks of NHT, reaching sleeping altitudes equivalent to 7100 m and spent at least 300 hours in NH. At rest a flow rate of 2 l O2/min is sufficient to keep PIO2 close to 50 mmHg even at the summit. For physical exercise of about 80% VO2max at the summit 6 l O2/min are required to maintain a PIO2 above 50 mmHg. Discussion NHT for preacclimatization seems to be the decisive element of the offered rapid ascent expeditions. An increased O2-flow rate of 8 l/min is not mandatory for climbing Mt Everest. Conclusions Preacclimatization using NH is far more important than the use of HFSO2. We think that NHT will be widely used in the future. The most effective regimen of preacclimatization in NH, the duration of each session and the optimal FIO2 are still unclear and require further studies.

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An analysis of commercially recommended profiles for normobaric preacclimatization

Tannheimer

Lechner

2021

Health Prmot Phys Act

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Introduction: Normobaric hypoxic training (NHT) for preacclimatization at home has found its way into commercial expedition mountaineering. Portable NH-generators produce a normobaric hypoxic gas mixture that can be inhaled using breathing masks at rest or during exercise or it can be pumped into lightweight tents for sleeping. These devices can be rented from commercial companies. Materials and methods: Prior to an expedition to Manaslu (8163 m) NHT was used for preacclimatization over a period of 10 days. Our regimen involved a greater increase in sleeping altitude (10 nights to reach 5400 m) than recommended by the rental company (30 nights to reach 3900 m). Results: No incidents occurred during NHT. Our regimen induced sufficient acclimatization to Manaslu Base Camp (4900 m), as evidenced by the fact that none of the expedition members suffered from AMS although they reached base camp within 2 days from Kathmandu – by helicopter flight to 3500 m and a one day walk the next day. Eight days after leaving Kathmandu, camp III was reached at 6850 m. Conclusions: At natural altitudes above 2500 m an increase of sleeping altitude should not exceed 300-500 m per day. Below 2500 m, there are no restrictions. It is therefore unclear why the company recommends such a slow increase in sleeping altitude. In our opinion, it is not necessary for healthy persons to start with a sleeping altitude below 2500 m. In contrast to natural altitudes, NH exposure can be instantly stopped if symptoms occur. Therefore, it seems safe to expose healthy persons to more liberal normobarichypoxic conditions.

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Rapid Acclimatization Strategies for High-Altitude Induction

Cited by 3 publications

References 105 publications

S1P prophylaxis mitigates acute hypobaric hypoxia‐induced molecular, biochemical, and metabolic disturbances: A preclinical report

S1P prophylaxis mitigates acute hypobaric hypoxia‐induced molecular, biochemical, and metabolic disturbances: A preclinical report

Rapid ascents of Mt Everest: normobaric hypoxic preacclimatization

An analysis of commercially recommended profiles for normobaric preacclimatization

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