Regarding your physical conditioning requirements for mountain climbing

When you see pictures of Mt. Fuji climbing posted on social media, you may have the impression that it is a "very easy mountain to climb" with happy smiles. Do not forget that Mt Fuji is over 3,000 meters (12,000 ft). Make sure you have a proper understanding of the physical ailments that you will encounter especially on Mt. Fuji.

  • Altitude sickness
  • Hypothermia
  • Heat stroke
  • Fatigue distress

Symptoms of altitude sickness

Altitude sickness is one of the most common reasons people give up trying to climb Mt. Fuji. To enjoy a safe and pleasant climb, try to prevent 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.

Preventative measures

  • 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.

<Effective preventative measures>
  • Before climbing, take a break for about 1-2 hours near the 5th station to acclimate to the altitude.
  • Walk at a slow, steady pace
  • Take a deep breath and exhale firmly from your stomach.
  • Frequent hydration (sports drinks are more effective than plain water)
  • Keep your periodic breaks short to prevent lowering your body temperature.
  • 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).

Countermeasures against altitude sickness

  • First, stop climbing and rest your body while consciously taking deep breaths.
  • When climbing with more than one person, it is important to talk to each other in order to detect signs of problems. 
  • Lowering altitude is the best solution. Lowering altitude and increasing oxygen intake usually heals on its own. Mt. Fuji doesn't run away. Don't insist on climbing, give top priority to returning home safely.

<Countermeasures after onset>
  • If the symptoms are severe, descend the mountain.
  • Keep warm and rest
  •  If you feel the symptoms are getting worse, go to a first aid station. 
<Brief memo>
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.

Symptoms of hypothermia

You may think "hypothermia" in midsummer? At higher elevation the temperature gets quite cold. For example, at the summit, the temperature is single digit centigrade in midsummer. In case of early July and late August, it is common for the temperature to drop below freezing. Please understand and prevent hypothermia.

  • Hypothermia is a condition in which the body temperature (core body temperature) of vital organs such as the brain and heart falls below 35°C. If 32-35°C it's mild, if 28-32°C it's moderate, if 20-28°C it's severe. 
  • If your body temperature drops due to exposure to wind for a long time while being wet (whether by rain or sweat) hypothermia may develop even in the middle of summer or at low mountain elevation. You become more prone to hypothermia when your body's heat difusion is disrupted by stress, etc. to the autonomic nerves which contracts the blood vessels.
<Main symptoms>
  • Whole body shivering, chills, drowsiness, staggered walking
  • Loss of consciousness, cessation of shaking, inability to stand
  • Coma, cardiopulmonary arrest

Looking at the above, you may have an image that hypothermia progresses gradually over a long period of time. Actually, in a mountain environment, consciousness disturbance occurs at an accelerated rate. The scary part is that when you first feel the chills and shivering, it goes quickly from there.

Preventative measures

 1) Keep your body warm and dry
  • Wear quick-drying underwear
  • Wear warm clothing such as fleece
  • Windproof and waterproof rainwear

 2) Frequent intake of high-calorie foods
  • Chocolate and nuts
  • Warm sweet drinks


Hypothermia countermeasures

 1) Move to a warm place to protect yourself from the wind and rain
  • Nearby hut
*Do not occupy toilets or hut storage rooms because you will be a nuisance to other people.
 2) Warm your body from the inside and out
  • Change wet clothes
  • Have a hot drink
  • Use emergency sheets when necessary
(after use, be sure to repack. Do not litter)
<Brief note>
Generally, the temperature drops by 0.6°C  (1.1°F) for every 100m in altitude. Also, as the wind speed increases by 1 m/s (2.2 mph), the wind chill temperature drops by 1.0°C (1.8°F). Even though the temperature is warm at the foot of the mountain, it can be much colder at the summit.
The temperature will drop depending on the weather and the time of day, so dress in layers to regulate your body temperature. 

Symptoms of heat stroke

At Mt. Fuji, one tends to notice only "altitude sickness" and "hypothermia" but there is also the risk of "heat stroke". In particular, there are no shade trees that can block the sun on the trails of Mt. Fuji. Since the back of your head is often exposed to direct sunlight for a long time, please be careful.

 <Main symptoms>
  • Dizziness/lightheadedness, profuse sweating, muscle cramps
  •      ↓
  • Headache, nausea, fatigue,  poor concentration/judgment
  •      ↓
  • Impaired consciousness, convulsion/seizure, body becomes hot, staggered walking

Preventative measures

  • Wear a wide-brimmed hat that also covers the back of the head.
(with a fastenable chin strap to prevent from blowing away by the wind)
  • Dress cool.
(Especially when descending mountains, there are cases where people get heatstroke because they don't adjust their clothes or drink enough water.)
  • If outdoors, remove your mask as appropriate.

  • Frequent hydration (sports drinks and oral rehydration solutions are effective)
  • (1.2 liters per day is a guideline. Especially for the Yoshida/Subashiri/Gotemba trails, make sure you have enough water for the descent.)


Countermeasures against heat stroke

  • Check for consciousness, if not → seek aid
  • Move to a cool place, loosen your clothes and cool your body. 
Apply a wet towel or a cold plastic bottle, to arteries, such as the neck, armpits and groin to  efficiently lower the core body temperature.
  • If the victim is able to drink on his/her own, replenish fluids and electrolytes. Do not forcibly drinking water while unconscious.
  • If symptoms do not improve →  seek aid

Fear of fatigue distress

Unlike "altitude sickness" or "hypothermia", "fatigue" means you are too tired to walk. 
No matter how hard it is, if you don't go down the mountain on your own, you won't be able to get home.
It's distressful when you can't go down the mountain by yourself.
The figure above is a graph showing the breakdown of the number of accidents during the climbing season in Subashiri / Gotemba / Fujinomiya / Summit trails. Distress due to fatigue increased from 2 cases and 14% in 2021 to 22 cases and 44% in the following year, a 30% increase. In the case of Yoshida Trail there is a difference in the transportation system. Although fatigue distress is not counted, the number of requests due to fatigue increased as well.
In 2022, there were still immigration restrictions to control COVID-19. After immigration restrictions were lifted in 2023, there are concerns that an increasing trend of fatigue distress will become more pronounced.
Regarding the transportation system in case of distress incidents.
Disstress incidents will be handled differently depending on the trails on Mt. Fuji.
In the case of the Yoshida Trail on the Yamanashi Prefecture side, the Mt. Fuji 5th Station General Management Center, which is operated by the prefecture, serves as a control center for information aggregation, etc. "Rescue teams" are organized by huts in cooperation with firefighters, etc. The injured and sick are brought down to the 5th station by a "crawler" transport vehicle. At the 5th Station, the injured are transported by ambulance to a local hospital or clinic.
In the case of Subashiri, Gotemba, Fujinomiya, and Summit trails, due to the difference in the number of injured and sick victims, these trails do not have a transportation system like Yoshida trail. Basically, the transportation is done by manpower by the police.
Crawlers are not taxis!
The photo on the right shows a vehicle, called a crawler, which is transporting goods to a hut. It also acts as a emergency transporter by the "rescue team" on the Yoshida trail as mentioned above. Emergency transportation by crawler is operated by a private enterprise. As such, the victim must pay for the transportation fee. In case of use of transport by crawler, the severity of victim's injury must require professional medical treatment. Upon arrival at the  5th station an ambulance will transport you to a local hospital or clinic. Occasionally, there are misunderstandings of this procedure, so please understand in advance.
Crawler operations incur various costs. Since the number of vechicles and drivers are limited, vehicles must be diverted to more serious life-threatening cases. A crawler is not a taxi. It's not something you can ride casually just because you're tired. It's also not just a matter of paying money. Again, please understand the circumstance. 

Preventative measures

1) Strengthen your physical conditioning!
  • Develop your legs by climbling nearby mountains
  • Endurance training
2) A mountain climbing plan that fits your current physical strength
  • Don't be overconfident (especially for middle-aged and elderly people).
  • Plan to arrive at the hut before sunset.
  • Especially for day climbers using a bus (whether or not you reach the summit), do your homework well in advance. Be sure you descend in time to take the last bus.