The design and installation of the hypoxic facility at the Olympic Sport Centre (OSC) Planica is the culmination of a 7 year collaboration between b-Cat (Netherlands) and the Department of Automation, Biocybernetics and Robotics at the Jozef Stefan Institute (Slovenia). The first hypoxic facility was installed at Gostilna Žerjav in the nearby village Rateče (Slovenia). The hypoxic apartment in this facility was used by athletes for hypoxic training and by alpinists for altitude acclimatisation in preparation for high altitude expeditions. In 2002, a hypoxic facility was installed in a hut maintaned by Golstilna Vovko near Novo Mest (Slovenia). In 2007, several rooms at the Rogla Hotel (Slovenia) were converted so that they could have hypoxic capabilities. In Spring 2007, as construction started on the Olympic Sport Centre Planica, IJS won the bid to install the hypoxic facility in this centre. Together with industrial partner b-Cat, the facility was installed the same year, and the first research project on the topic of hypoxic training of athletes initiated in the Fall of 2007. Since then a variety of projects have been conducted, which are described in the Research programme section.
The areas within the OSC Planica that can be rendered hypoxic are: 10 double rooms (the level of hypoxia can be regulated in each room separately), the entire floor (10 double rooms, communal living room and dining room), half of the floor (5 double rooms, communal living room and dining room), laboratory, and gymnasium (basketall court). The capacity of the hypoxic gas generator is such that the oxygen fraction of the air in the entire floor and laboratory can be reduced to simulate altitudes of 5000m. The oxygen fractions in each room separately can be maintained at levels simulating altitudes in excess of 7000m. The oxyygen fraction in the gymnasium can be reduced to simulate altitudes of 3000m.
How is a hypoxic ambient achieved?
Vacuum-Pressure Swing Adsorption: generating the oxygen-depleted gas mixture
The essential component of the Hypoxic facility is the Vacuum-Pressure Swing Adsorption (VPSA) system. This system contains two silos containing proprietory adsorbers, which adsorb oxygen moleculrs when air passes through the mixture. Once the mixture is saturated, and no longer has the capacity to adsorb oxygen, the adsorption function is autmatically switched to the second adsorber-containing silo. The adsorbent in the first silo is then regenerated by creating a vacuum and exhausting the adsorbed oxygen. The name VPSA is derived from the manner inwhich the system works: intermittent pressure and vacuum is applied to the adsorbent-containing silo.
Control Unit: regulating the oxygen concentration in the facility
The control unit of the system regulates the delivery of the oxygen-depleted gas mixture to all rooms that are activated. Air in each activated room is sampled at 15 minute intervals and analysed for oxygen and carbon dioxide concentration. Prior to each measurement, the gas analysers are automatically calibrated with a calibrated gas mixture. The measured values are compared with the pre-set values for each activated room. In the event that the oxygen concentration is too high, the system continues delivering the hypoxic gas mixture to the room. If the oxygen concentration in a room are too low, then several actions are mediated in sequence. Firstly, a solenoid valve prevents further delivery of hypoxic gas to the room. If this does not correct the oxygen concentration in the room, then a large ventilator situated in each room is activated, drawing air from the external environment into the room.
Several safety features have been incorporated into the system, to prevent oxygen levels dropping to unacceptable limits. The regulation of the oxygen levels in each room have been described above in the "Control Unit" section. When the oxygen levels decrease below the pre-set levels an audible alarm is initiated by the control unit. In addition, each occupant of the hypoxic facility is issued with two devices: a personal clip-on type oxygen analyser, and an oxymeter. The first displays the oxygen contration of the air in close proximity to the wearer, and alerts the wearer when oxygen decreases below the pre-set value. The oxymeter is worn on a finger intermittently, and informs the wearer of hir/her heart rate and blood oxygen saturation. All 15-min values of the oxygen and carbon dioxide concetrations in all activated rooms are stored and archived.
Carbon Dioxide Scrubber
A carbon dioxide scrubber is also attached to the laboratory. Since the laboratory is normally occupied by many individuals conducting research or training, the CO2 scrubber is activated to prevent elevations in the carbon dioxide level in the ambient air. The CO2 scrubber operates independently of the VPSA.