Cognitive effects of mild, acute hypoxia under normobaric conditions?

February 17, 2014

Seeking further scientific evidence to inform supervision decisions, the Swedish Safety Radiation Authority (SSM) recently decided to fund a research project encompassing a literature study and an experiment focused on cognitive effects (e.g. perception, memory, problem solving) of mild, acute (i.e. without acclimatization) hypoxia under normobaric conditions (i.e. sea level barometric pressure). In competition with some of Sweden’s top universities and research institutes, GEISTT AB tendered and was selected by SSM to conduct this important piece of research.

To conduct the experiment, GEISTT has established a sub-contract with QinetiQ Flight Physiology Center at Malmen Air Force Base outside Linköping, Sweden, for access to top-class experimental environments and medical expertise. The experiment sessions are currently being conducted, and the results will be delivered by GEISTT to SSM during the fall/winter 2014 to support their supervision and ultimately their upcoming renewed decision on a prolonged/permanent exemption and more wide-spread use of this fire prevention method at Swedish nuclear power stations.


The use of reduced oxygen concentrations has become an increasingly popular fire prevention method, in addition to the frequent use for physical exercise under simulated high-altitude conditions and for storing important materials (e.g. in archives and at museums). Early 2013, one of the operational Swedish nuclear power stations received a temporary two-year exemption to implement reduced oxygen for fire prevention to meet supervision requirements in spaces with critical, redundant systems. The implemented solution reduces the oxygen concentration from approx. 21% under sea level barometric conditions to approx. 15% by adding more nitrogen to the gas mixture. However, personnel still has to move in and out of those spaces for work without any acclimatization.

The state of experiencing reduced oxygen in the breathing air is called hypoxia. The effects of hypoxia on physical performance has been extensively studied, for example in mountain climbing and aviation. However these studies has primarily been focused on hypobaric hypoxia (i.e. hypoxia under barometric pressure lower than sea level), and primarily investigating the physiological effects on the human under such conditions. Furthermore, far more studies have been conducted on severe hypoxia on altitudes/simulated altitudes in the range of 5.000-10.000 meters, rather than milder stages of hypoxia such as 15% oxygen which corresponds to approx. 2.700 meters. The method used for fire prevention in the Swedish power station is not generated from reduced barometric pressure, but instead by reducing the oxygen concentration in the room air by replacing it with additional nitrogen. Hence, the barometric conditions are normobaric (i.e. sea level barometric conditions) rather than hypobaric (which is the case for higher altitudes).