Pain Perception Threshold in Young High-Altitude Natives After Acute Exposure to Severe Hypoxic Conditions

Previous studies indicate that individuals at high altitudes have a lower pain threshold than those living at sea level. This study evaluates the differences in pain perception among young people living at an altitude of 3800 m and after acute exposure to a severe hypoxic environment at more than 5100 m. Fourteen people (BMI of 22.6 ± 1.2 and age of 23.3 ± 1.9 years) residing in the city of Puno (3825 m) participated in an ascent to the Populated Center of La Rinconada (>5100 m). The unilateral ischemia pain provocation test was used, applying pressure with a manual sphygmomanometer to generate transient ischemia in the arm while the patient opens and closes their hand. Onset, peak, and resolution times of pain, heart rate, and oxygen saturation were recorded. At their residence altitude of 3828 m, the mean hemoglobin was 16.16 ± 2.29, while at 5100 m, mean hemoglobin increased to 17.57 ± 1.74. The average time to pain onset in the right arm was 30.43 s ± 14.15 at 3828 m, whereas at 5100 m above sea level, the pain perception was at 31.00 s ± 19.01. At 3828 m, the average time until pain sensation in the left arm was 19.93 s ± 9.44 and increased to 23.07 s ± 10.83 at 5100 m. During exposure to a severe hypoxic environment, the pain perception threshold was similar between 3828 m and 5100 m above sea level.