Risk1: Altitude sickness
What happens if you get altitude sickness?
Symptoms of altitude sickness
- Altitude sickness is a condition caused by a low oxygen level in the blood.
- Continuing to climb will make the symptoms worse.
- Lack of sleep and poor physical condition tend to make symptoms worse.
＜Main symptoms＞
- Headache, dizziness, feeling faint
- Feeling tired and lethargic
- Loss of appetite, nausea, vomiting, etc.
- Fatal conditions such as cerebral edema and pulmonary edema may also occur.
Why does altitude sickness occur?
As altitude increases, atmospheric pressure decreases, and the oxygen concentration in the atmosphere also decreases. In the case of Mt. Fuji, if the oxygen concentration at sea level is 100%, it will be approximately 70% at an altitude of 3,000m and approximately 65% at the summit of Mt. Fuji (Kengamine) at 3,776m. Inevitably, the oxygen taken into the lungs through breathing becomes diluted, and the oxygen saturation level (SpO2) in the blood decreases, causing various functional disorders in the body.
On the other hand, the body has the ability to adapt to altitude and maintain the required amount of oxygen intake, and by climbing while properly acclimatizing to altitude, symptoms of altitude sickness can be avoided or alleviated. However, this varies depending on your constitution and physical condition, so if you are going in a group, you need to pay attention to the physical condition of each member.
Preventive measures
Before attempting to climb Mt. Fuji, we recommend that you climb several mountains to gain the stamina to continue walking all day long and improve your cardiovascular function. (We recommend doing some trekking in your home country to get used to your feet before coming to Japan)
Points to remember on the mountain
- Before climbing, take a break for about 1-2 hours near the 5th station to acclimate to the altitude.
- If you hold off on going to the toilet or refrain from drinking water, your metabolism will become low and you will be more likely to develop symptoms of altitude sickness. Therefore, drink water frequently.
- It is not recommended to fall asleep upon arrival at your hut. When you sleep, your breathing becomes shallow. If you are not acclimatized, your breathing becomes shallow and you are more likely to get altitude sickness. When you arrive at your hut, you should take about an hour to organize your luggage, take in the scenery, etc. while getting used to the altitude then take a good rest.
- Children have weak cardiopulmonary function, especially if they are climbing Mt. Fuji for the first time so they may not be able to get enough sleep. They are at greater risk of developing altitude sickness than adults. Pay close attention to your child, don't overdo it.
>> For walking tips and what to do if you get altitude sickness, check out "While Climbing"
＜Brief memo＞
Each group should have a pulse oximeter to measure their blood oxygen level. Record and manage the blood oxygen levels of the members regularly. This makes detecting signs of altitude sickness easier. In general, if the blood oxygen level falls below 90%, this is a sign of altitude sickness, and if it falls below 80%, it is dangerous (they should descend immediately).
Occasionally, there are climbers who breathe commercial canned oxygen while taking breaks.
It seems that climbers can breathe easily while they are inhaling canned oxygen. The moment they stop inhaling the oxygen cans, the oxygen concentration will return to that altitude. Using canned oxygen makes it easier to get altitude sickness.
The important thing is to acclimate your body to the oxygen concentration at that altitude. Only use canned oxygen temporarily when it's really painful.
Do not rely on it too much. Rather, take deep breaths to acclimate to the altitude. If you can't climb without canned oxygen, it's better to stop climbing and descend immediately.