Disclaimer: This article is not written by a medical professional, and we are not responsible for any issues related to mountaineering or the physical condition of the page visitor. Please consult a qualified medical professional regarding your personal health before climbing.

Introduction

Climbing Mt. Fuji is a once-in-a-lifetime experience, but many climbers face a common challenge—altitude sickness. About 30% of climbers experience mild symptoms, and in some cases, it can become severe enough to force them to turn back even if they still have enough stamina to climb. Every year, we see many young, physically active climbers forced to descend due to altitude sickness. The summit success rate for Mt. Fuji is estimated to suggest around 70〜80% of climbers reach the summit during the official climbing season. To prevent altitude sickness and ensure climbers enjoy the summit while preserving their strength, JIN’s tours encourage a slower pace, resulting in over 95% of participants successfully summiting. To improve your chances of reaching the summit safely, it’s important to understand altitude sickness, how to prevent it, and what to do if you experience symptoms.

What is Altitude Sickness?

Altitude sickness, or Acute Mountain Sickness (AMS), occurs when your body cannot adjust quickly enough to lower oxygen levels at high altitudes. Symptoms typically appear above 2,500m (8,200ft) and can worsen as you climb higher. Since Mt. Fuji is 3,776 meters (12,389 feet) above sea level, the oxygen level is significantly lower than at sea level.

Common Symptoms of Altitude Sickness

• Headache

• Dizziness

• Nausea or loss of appetite

• Shortness of breath

• Fatigue

• Difficulty sleeping

• Swelling in hands or feet

In more severe cases, it can lead to High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE), which are life-threatening conditions. If you or a fellow climber experience confusion, extreme weakness, or difficulty walking, immediate descent is necessary.

How to Prevent Altitude Sickness on Mt. Fuji

The best way to deal with altitude sickness is to prevent it before it starts. Here are the most effective prevention methods:

0. Sleep Well and Stay Hydrated the Day Before

Your preparation starts before you even set foot on the trail. Poor sleep or dehydration before your climb increases the risk of altitude sickness.

📌 Pro Tip:

• Get at least 7-8 hours of sleep the night before your climb.

• Avoid alcohol, as it dehydrates your body and affects sleep quality.

• Drink plenty of water throughout the day before your climb (but avoid excessive amounts right before bed).

• Eat a light, balanced meal with carbohydrates and protein to provide sustained energy.

1. Climb Slowly and Maintain a Steady Pace

Your body needs time to adjust to the altitude. Walk at a slow, steady pace that keeps your breathing under control. If you feel out of breath, slow down.

📌 Pro Tip:

• Stick to a slow and consistent pace, even if you feel energetic at the beginning.

• If you feel tired, walk directly behind your guide to match their controlled pace.

2. Take Frequent Breaks and Acclimatize

The tour schedule includes at least one hour of acclimatization at the 5th station before the hike begins. Use this time to relax, hydrate, and adjust to the altitude.

📌 Pro Tip:

• After every 30-40 minutes of progress, rest for a few minutes before moving on.

• If you feel symptoms, take a longer break before deciding whether to continue.

3. Stay Hydrated

Dehydration increases the risk of altitude sickness. Aim to drink at least 2 liters(67.6 fl oz / 0.53 gal) of water per day while climbing.

📌 Water Intake Guide:

• Every rest stop: Drink 1/4 to 1/3 of a 500ml(16.9 fl oz / 0.13 gal) water bottle.

• At the 7th station: At least 500ml(16.9 fl oz / 0.13 gal) should be consumed.

• Before reaching the mountain hut (8th station): At least 1.5 liters(50.7 fl oz / 0.4 gal) should be consumed.

• At night before sleeping: Drink an extra 500ml(16.9 fl oz / 0.13 gal).

4. Control Your Breathing

At high altitudes, the oxygen level is lower, making it harder to breathe. Adjust your breathing to avoid oxygen deprivation.

📌 Pro Tip:

• Use “pursed-lip breathing” (inhale through your nose, exhale slowly through pursed lips).

• Practice diaphragmatic breathing (deep belly breathing) to maximize oxygen intake.

• Do deep breathing exercises with your group to stay oxygenated and alert.

5. Stretch Regularly

Stretching helps improve blood circulation and relieves tension. Focus on loosening your shoulders and legs.

📌 Pro Tip:

• Do a quick 5-minute stretching session at each break.

• If you feel light-headed, gently massage your shoulders to stimulate circulation.

6. Dress in Layers and Keep Warm

Cold temperatures can make altitude sickness worse. Adjust your clothing layers frequently to stay warm but avoid overheating.

📌 Pro Tip:

• Wear moisture-wicking base layers to stay dry.

• Keep your head and hands warm with gloves and a hat.

• Drink warm beverages like tea or soup to maintain body temperature.

7. Eat Smart

At high altitudes, digestion slows down, so eat light but frequent meals.

📌 Pro Tip:

• Chew food thoroughly to help digestion.

• Avoid overeating—stick to about 80% of your normal portion.

• Bring snacks like energy bars, nuts, and dried fruit for quick energy.

8. Improve Your Sleep at the Mountain Hut

Sleeping at high altitudes can be difficult. Poor sleep can make altitude sickness worse.

📌 Pro Tip:

• Wait 30 minutes after eating before sleeping to allow digestion.

• Sleep on your side instead of your back to improve breathing.

• Keep a water bottle by your pillow to drink if you wake up.

⚠︎Note: Bullet climbs that do not stay overnight in a mountain lodge and aim for the summit all at once through the night are not recommended due to the various risks involved. The summit rate is higher with or without a guide if you stay overnight in a lodge and take a rest.

9. Stay Positive and Mentally Strong

Mental stress and anxiety can make altitude sickness worse. Enjoy the climb, focus on your progress, and celebrate small achievements.

📌 Pro Tip:

• Set mini-goals (e.g., “Let’s reach that next hut, then take a break”).

• Talk with fellow climbers and guides to stay engaged.

• For a more relaxed and confident climb, consider joining an experienced guide. They’ll handle the complexities of weather, itinerary, and health considerations, allowing you to focus on the challenge itself. Plus, their expertise in carrying supplemental oxygen and coordinating with rescue teams provides invaluable support in case of emergencies.

What to Do If You Get Altitude Sickness

Even with preparation, altitude sickness can still happen. If you start to feel symptoms, follow these steps:

1. Stop and Rest Immediately

• Do not continue climbing if symptoms are getting worse.

• Sit down, take deep breaths, and drink water.

2. Increase Oxygen Intake

• Use pursed-lip breathing or a breathing exercise to improve oxygen levels.

• Some climbers use portable oxygen canisters, but they only provide temporary relief.

3. Descend or Seek Help if Symptoms Worsen

• If symptoms do not improve after resting, descending is the best option.

• Severe symptoms like confusion, inability to walk properly, or vomiting mean you must descend immediately or seek emergency assistance immediately. There are first-aid stations at some mountain huts and along the trail.

Location of first aid station (*Please check the details of the opening period.)

• Yoshida Route: First aid stations are located at the fifth station of the Subaru Line(2,305m/7,562ft), next to Kamaiwakan Hut(2,700m/8,858ft) at the seventh station, and next to Taishikan Hut(3,100m/10,171ft) at the eighth station.

• Fujinomiya Route: The first aid station (Mt. Fuji Sanitation Center) is located next to Ikeda-kan(3,250m/10,662ft) at the eighth station.

• Subashiri Route: There is no first-aid station.

• Gotemba Route: There is no first-aid station.

Final Tips for a Safe and Enjoyable Climb

Reaching the top of Mt. Fuji is an amazing achievement, but your health and safety come first. By taking the right precautions—climbing slowly, hydrating, breathing properly, and listening to your body—you can greatly reduce your risk of altitude sickness and increase your chances of a successful and enjoyable climb.

Climb safe, stay strong, and enjoy the adventure!🏔️✨