Last week there were reports of another breakthrough in the fight against altitude sickness. Researchers at The Roslin Institute at the University of Edinburgh have discovered that the symptoms commonly suffered by those at altitude are in fact the result of two completely separate syndromes which just so happen to strike above 2500m.

Both of these illnesses are triggered by falling oxygen levels prevalent above 2500m. Researchers used as their study 292 people at altitudes between 3650m and 5200m in Bolivia and on Mount Kilimanjaro. Using advanced software that grouped people according to their genetic make-up, they found that of all the symptoms of AMS (acute mountain sickness, aka altitude sickness), the only common one experienced by all parties was fatigue. Sleep disturbance (another very common symptom) was another common symptom, but this was not necessarily accompanied by a headache; conversely, 40% of those suffering headaches did not report any sleep disturbance.

The scientists conclusions were that the correlation between headaches and sleep disturbance are so poor as to indicate that the two are in fact manifestations of completely separate conditions and not all part of the same illness that, up to now, we have thought of as ‘altitude sickness’.

As Dr Ken Baillie, of the Roslin Institute, explained “For more than two decades we have thought of altitude sickness as a single disease. We have now shown that it is at least two separate syndromes that happen to occur in the same people at a similar time. Studying these syndromes in isolation will make it easier to understand the cause of each one, and to test new treatments.”
This groundbreaking news follows another study that we first wrote about back in December, in which scientists claimed to have discovered the underlying cause of altitude sickness. In this study, researchers looked at how the heart reacts to the oxygen levels using ultrasound techniques. Using only 34 volunteers, who were measured at sea level and again at high altitude (in this 3842m at the top of the cable car running up the Aiguille de Midi), scientists discovered that those who developed at least moderate symptoms had poor function in their heart’s right ventricle and its ability to pump blood.

The scientist who led the study, Dr Rosa Maria Bruno, explained “If these results are confirmed by larger studies, it will be possible to identify vulnerable individuals and suggest particular behaviours and drugs.” Though as she also pointed out, the test can at the moment only be done on people who have spent at least 4 hours at high altitude; though in time it is hoped that it can be developed so it can be done much sooner.