Differential effects of high-altitude exposure on markers of oxidative stress, antioxidant capacity, and iron profiles

Abstract

High altitude (HA) exposure may stimulate significant physiological and molecular changes, resulting in HA-related illnesses. HA may impact oxidative stress, antioxidant capacity and iron homeostasis, yet it is unclear how both repeated exposure and HA acclimatization may modulate such effects. Therefore, we assessed the effects of weeklong repeated daily HA exposure (2,900m to 5,050m) in altitude-naïve individuals (n=21, 13 females, mean ± SD, 25.3 ± 3.7 years) to mirror the working schedule of HA workers (n=19, all males, 40.1 ± 2.1 years) at the Atacama Large Millimeter Array (ALMA) Observatory (San Pedro de Atacama, Chile). Markers of oxidative stress, antioxidant capacity and iron homeostasis were measured in blood plasma. Levels of protein oxidation (p<0.001) and catalase activity (p=0.023) increased and serum iron (p<0.001), serum ferritin (p<0.001) and transferrin saturation (p<0.001) levels decreased with HA exposure in both groups. HA workers had lower levels of oxidative stress, and higher levels of antioxidant capacity, iron supply and hemoglobin concentration as compared to altitude-naïve individuals. Upon a second week of daily HA exposure, changes in levels of protein oxidation, glutathione peroxidase and nitric oxide metabolites were lower as compared to the first week in altitude-naïve individuals. These results indicate that repeated exposure to HA may significantly alter oxidative stress and iron homeostasis, and the degree of such changes may be dependent on if HA is visited naïvely or routinely. Further studies are required to fully elucidate differences in HA-induced changes in oxidative stress and iron homeostasis profiles amongst visitors of HA.

Optimal type and dose of hypoxic training for improving maximal aerobic capacity in athletes: a systematic review and Bayesian model-based network meta-analysis

“…(Rusko et al, 2004;Wilber, 2007;Gore et al, 2013). The U-shaped curve and upper limit of the reasonable dosage are novel findings that may arise from the adverse effects exerted by prolonged chronic hypoxia such as disrupted sleep quality (Kinsman et al, 2005;Sargent et al, 2013), oxidative disorders or pulmonary edema (Gaur et al, 2021;Rytz et al, 2022), accumulated fatigue (Bergeron et al, 2012;Koehle et al, 2014), etc. Moreover, the effect of training site altitude and type of hypoxic residential environment on the efficacy of HL was investigated.…”

“…Despite variations in selected indicators, the effective hypoxic dosage in previous studies aligns closely with the reasonable range explored in this study ( Rusko et al, 2004 ; Wilber, 2007 ; Gore et al, 2013 ). The U-shaped curve and upper limit of the reasonable dosage are novel findings that may arise from the adverse effects exerted by prolonged chronic hypoxia such as disrupted sleep quality ( Kinsman et al, 2005 ; Sargent et al, 2013 ), oxidative disorders or pulmonary edema ( Gaur et al, 2021 ; Rytz et al, 2022 ), accumulated fatigue ( Bergeron et al, 2012 ; Koehle et al, 2014 ), etc.…”

The Telomere-Telomerase System Is Detrimental to Health at High-Altitude

“…Our present findings would correlate with athletes that utilize altitude training to increase their exercise capacity; where being in a hypoxic environment would improve their performance at sea level or acclimatize to sports events at HA. A recent study reported that repeated and continuous exposure to HA might significantly alter oxidative stress and antioxidant capacity among HA visitors [63]. Another review highlighting the effect on telomere length and telomerase activity due to physical exercise concluded that regular aerobic activity, of moderate to vigorous intensity, preserves telomere length among athletes [27].…”

Disrupted gut microbiota aggravates working memory dysfunction induced by high-altitude exposure in mice

“…It is sensitive to pathophysiological changes such as reduced antioxidant capacity, and oxidative damage can impede prefrontal-dependent memory function by reducing the production of new neurons ( Huang et al, 2015 ). A previous study showed that the levels of protein oxidation and catalase activity increased, and serum iron, serum ferritin, and transferrin saturation levels decreased with high-altitude exposure, indicating that the high-altitude environment may affect antioxidant capacity and iron homeostasis ( Rytz et al, 2022 ). The level of antioxidant capacity is closely related to the influence of high altitude, which was also found by Zhang et al (2015) during research on the effect of hyperbaric oxygen preconditioning in plain migrant plateau personnel.…”