High-rolling research
Working at mild altitudes has been put to the test in a collaborative research project run by the RAAF Institute of Aviation Medicine, as Corporal Simone Liebelt reports.

 

A professional athlete is monitored while cycling at mild altitude in the hypobaric chamber at the RAAF Institute of Aviation Medicine.

Hypobaric chamber technician, FSGT Mark Gegenhuber from the RAAF Institute of Aviation Medicine, watches as cyclist Stuart Smith from the SA Sports Institute is tested by Rob Aughey, a lecturer of exercise physiology from the University of Canberra.

Photos by CPL Jeremy Patten

A GROUP of elite cyclists went for a ride of a different kind recently when they pedalled up to 9000 feet above sea level in the hypobaric chamber at the RAAF Institute of Aviation Medicine (AVMED), RAAF Base Edinburgh.

They were volunteers in a major altitude and performance research project being conducted by AVMED in collaboration with the Australian Institute of Sport, the South Australian Sports Institute and the Universities of Canberra and Bayreuth, Germany.

The project – which took more than 12 months to plan – examined the issue of human performance while working under exposure to relatively low altitudes, according to Wing Commander Greg Hampson, Commanding Officer AVMED.

“Traditional aviation physiology teaches us that you can perform from sea level to 10,000ft pretty normally and then you require oxygen above that height, but we know in all biological systems that there’s no black and white line,” Wing Commander Hampson said.

“We had anecdotal evidence of crew noting decreased physical and cognitive performance at levels of altitude below 10,000ft, for example, while performing physical tasks such as moving around the aircraft or loading and unloading the aircraft at altitude.”

He said this research – which is a first for AVMED – particularly applied to ADF aircrew, like loadmasters, who operate in unpressurised conditions such as helicopters or transport aircraft, and in aircraft depressurised for emergency or tactical operations.

“The whole point of the project was to look at cardiovascular and respiratory response to different levels of workload at mild altitudes of 3, 6 and 9000ft,” he said.

“We looked at the work capacity and the performance that individuals could achieve at these different heights, as well as their recovery period and the variation between different people.”

He said during a two-week period, the volunteer cyclists from the SA Sports Institute did a number of runs in the hypobaric chamber under observation of research personnel.

Blood tests were taken before the runs and then athletes were monitored in the chamber, where measurements were recorded during acute exposures to the various altitudes.

“We used these high-calibre cyclists because they were used to this sort of voluntary program and were doing the work they were familiar and trained to do,” Wing Commander Hampson said.

“Throughout the exercise, both the athletes and the people recording the data in the chamber were blind to the altitude, so they would perform to the best of their ability, no matter what height they were at.

“We found that we were getting a significant drop in performance when we got to about 6000ft, and that people needed more time to recover after working at the higher altitudes.”

He said the data would be analysed so results could be applied to any future operational problems in ADF aircraft.

“Acute hypobaric hypoxia is the single greatest physiological hazard during flight at altitude,” he said.

“[With this research], we are hoping to show that while you can perform, you have a reduced level of performance as you go up in altitude because of the reduction of the partial pressure of oxygen.

“For example, if you’re doing something at hypoxic level, then this is going to change your respiration, so therefore your emergency oxygen system might only last you eight minutes, when you would expect it to last you 20 minutes.

“Hopefully we can use this data to predict the expected decrease in performance at lower altitudes.

“This will allow us to look at whether an oxygen system would be required or whether work rates need to be adjusted for coping with other physiological stresses, such as temperature.”

For further information on AVMED’s role in research, training and developments in the field of aviation medicine, visit http://intranet.defence.gov.au/raafweb/sites/AVMED

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