The human body can perform best at sea level, where the atmospheric pressure is 101,325 Pa. The concentration of oxygen (O2) in sea-level air is 20.9%, so the partial pressure of O2 (pO2) is 21,136 Pa. In healthy individuals, this saturates hemoglobin, the oxygen-binding red pigment in red blood cells. However, atmospheric pressure decreases exponentially with altitude while the O2 fraction remains constant to about 100 km, so pO2 decreases exponentially with altitude as well. The percentage oxygen saturation of haemoglobin (SpO2), an important vital sign, determines the content of oxygen in blood. When pO2 drops, it is hard for climbers to breathe and the saturation of oxyhemoglobin begins to plummet, then the body responds with altitude acclimatization.
The effects of high altitude on humans are considerable. It can lead to medical problems, from the mild symptoms of acute mountain sickness (AME) to the potentially fatal high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). Higher the altitude, greater the risk. However, people nowadays enjoy travelling and they might go to high altitude places such as Tibet, Paro Valley, Katmandu and Machu Picchu. Many of them may be enthusiastic about climbing to high altitude because they view it as a cool challenge. However, as they climb at high altitude, there is much less oxygen available for them to breathe and their oxygen saturation levels will continue to decrease, which might cause altitude acclimatization. So using a pulse oximeter to monitor SpO2, an important index to reflect people’s physical condition at high altitude lacking of oxygen, is essential for them. The table below shows the connection between SpO2 index, physical condition and the corresponding measures to solve the unfitness.
So what does monitoring SpO2 can do for people in high altitude? Recently, a study published by scientists from Finland pointed out that a simple pulse oximetry test at altitude may predict who is most likely to succumb to altitude illness. This science could be very useful - both predictively and diagnostically. If we can use the methods from this research, we could test rest and exercise pulse oximetry to give us yet another information to round out the clinical examination. And expedition leaders, wondering whether they should spend another rest day at altitude, could test their groups to add even more information to their daily screening to evaluate how well the group is acclimatizing. In this case, the use of potable pulse oximeter can prevent people suffering altitude acclimatization.As pulse oximeter in current market is easy to use and portable, it is strongly recommended to monitor the travelers’ oxygen levels and help determine whether they have a health issue or simply are breathing in lower levels of oxygen because measuring blood oxygen saturation (SpO2) is very relevant for people traveling at high altitude as it can bring to light potentially life-threatening hypoxic conditions.