This WP specifically aims to elucidate the effects of IEK on hypoxic tolerance and the development and severity of AMS symptoms, blood and tissue oxygenation status, as well as sleep quality during an episode of acute exposure to severe hypoxia.
Acute altitude exposure impairs exercise tolerance and performance, decreases the rate of maximal oxygen uptake (V̇O2max), cognitive function and sleep quality, and often also induces symptoms of acute mountain sickness (AMS). Previous studies have clearly indicated that ketone bodies exert a neuroprotective effect under hypoxic-ischemic conditions as well as improve hypoxic tolerance in rodents. In support of these earlier observations, recent pilot experiments in young volunteers in our laboratory provide proof of concept that IEK can attenuate oxygen desaturation during exercise in hypoxia. Therefore, given that impaired exercise tolerance in hypoxia is primarily due to impaired oxidative energy production in active tissues (brain and muscle), we hypothesize that IEK can increase blood and tissue (muscle and brain) oxygenation status in hypoxia and thereby enhance global hypoxic tolerance, as well as improve exercise tolerance and endurance exercise performance.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
16
A total of 240g ketone ester supplementation will be provided in one of the 28h experimental sessions in order to establish intermittent exogenous ketosis. Sucralose (5% w/w) is added to the ketone ester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate
Water, 5% sucralose (w/w), octaacetate (1 mM)
KU Leuven
Leuven, Vlaams-Brabant, Belgium
Change in incidence of acute mountain sickness symptoms
Scored by Lake Louise Scoring system
Time frame: Hour 0 - Hour 4 - Hour 10 - Hour 24 - Hour 28
Change in oxygenation status of brain, blood, muscle
Measured by NIRS, pulse oximetry, blood samples
Time frame: Hour 1 - Hour 4 - Hour 10 - Hour 24 - Hour 28
Change in cerebral blood flow
Measured using duplex ultrasound
Time frame: Hour 1 - Hour 4 - Hour 10 - Hour 24 - Hour 28
Time in hypoxia
Total time that subjects were able to comply to the experimental protocol and supplementation protocol
Time frame: From start of hypoxic exposure until subjects are too sick to comply to (supplementation) protocol or until end of protocol, up to 29 hours
Sleep quality
Measured using polysomnography
Time frame: Throughout the entire duration of the night, up to 9 hours after individual bedtime
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