Headaches are a common symptom of altitude sickness. But they may not have to be. Researchers from University Hospital Frankfurt have turned to NIR spectroscopy to study ailments associated with altitude sickness, namely its tendency to reduce oxygen and blood flow to the brain, which often leads to headaches. The researchers monitored this in six people climbing Mount Kilimanjaro, the world’s highest free-standing mountain range at 5895 meters (19,340 feet) above sea level. Using NIR spectroscopy, they monitored changes in the concentration of both oxygenated and deoxygenated hemoglobin in the subjects’ blood supply to the brain to determine whether abnormal breathing patterns were reducing that supply, and potentially exacerbating the effects of altitude sickness. “The lack of oxygen at high altitude causes the climbers to hyperventilate, which leads to a decline of CO2 in the blood,” said researcher Peter Stein, who is in the department of anesthesiology, intensive care medicine and pain therapy at University Hospital Frankfurt. “The decline of CO2 leads to episodes of hypoventilation or even apnea. As a consequence, the oxygen level drops, causing an arousal and subsequent hyperventilation.” In their study, the researchers discovered that abnormal breathing patterns caused periodic changes in the concentration of oxygenated and total hemoglobin, but not in the concentration of deoxygenated hemoglobin. This indicates that although abnormal breathing patterns did alter the flow of blood into the climbers’ brains, it didn’t reduce the amount of oxygen reaching their brain tissue. The researchers also discovered, however, that climbers experiencing the most extreme periodic changes in hemoglobin concentrations in the brain were also found to be those suffering most from headaches at high altitudes. “Our experiments reveal a pathomechanism contributing to the aetiology of the most common symptom of altitude sickness: headache,” Stein said. “I hope that based on our findings it will be possible to develop new therapeutic approaches that help to increase comfort and safety for climbers in the future.” The researchers have found that after a few days, most people naturally acclimate to the climate, which greatly reduced or eliminated their symptoms. The research is published in Journal of Near-Infrared Spectroscopy. (doi: 10.1255/jnirs.1088) For more information, visit: www.kgu.de