Into Thick(er) Air? Oxygen Availability at Humans' Physiological Frontier on Mount Everest

Global audiences are captivated by climbers pushing themselves to the limits in the hypoxic environment of Mount Everest. However, air pressure sets oxygen abundance, meaning it varies with the weather and climate warming. This presents safety issues for mountaineers but also an opportunity for public engagement around climate change. Here we blend new observations from Everest with ERA5 reanalysis (1979-2019) and climate model results to address both perspectives. We find that plausible warming could generate subtle but physiologically relevant changes in summit oxygen availability, including an almost 5% increase in annual minimum VO₂ max for 2°C warming since pre-industrial. In the current climate we find evidence of swings in pressure sufficient to change Everest's apparent elevation by almost 750 m. Winter pressures can also plunge lower than previously reported, highlighting the importance of air pressure forecasts for the safety of those trying to push the physiological frontier on Mt. Everest.

Altered Visual Plasticity in Morbidly Obese Subjects

Growing evidence indicates a close link between energy metabolism and neural plasticity as obesity is associated with alterations of cognitive functions, memory, and hippocampal neurogenesis. However, it is still unknown whether obesity can affect low-level sensory plasticity. Here we investigated this issue by probing early visual plasticity induced by short-term (2 h) monocular deprivation in a group of adult volunteers with a wide range of Body Mass Index (BMI), from normal weight to morbid obesity. We found that the effect of monocular deprivation decreased with increasing BMI, and morbidly obese subjects (BMI>40) failed to show the homeostatic plasticity effect seen in normal-weight participants. In addition, morbidly obese subjects exhibited altered binocular rivalry dynamics compared with normal-weight observers. These results show for the first time that the impact of obesity observed at the neural and cognitive level extends to basic sensory processing and plasticity.

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Cognitive decline occurs in obesity suggesting altered high-level brain plasticity

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Low-level sensory plasticity in adults declines with increasing body mass index

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Morbidly obese subjects show altered visual plasticity and interocular interactions