At high altitudes, the air is thinner, this can cause altitude sickness (also known as Acute Mountain Sickness (AMS)) as the body adjusts to decreased oxygen levels. There are several methods to avoid and treat altitude sickness. Most of these methods involve reducing stress on the body as it adjusts to higher altitudes.
Different people can suffer from altitude sickness at different levels. But there are basic guidelines for acclimatization, to reduce the likelihood of suffering from altitude sickness. It is best to increase your altitude slowly. Avoid flying directly to high altitude locations (over 3000 meters), and progress upwards slowly, not too fast. Guidelines recommend that you take 2-3 days to adjust to high altitudes before ascending over 3000m, avoid climbing 300-500m per day and take a rest day after every 600-900m you ascend or every 3-4 days. If you follow these guidelines and still experience altitude sickness you should begin descending to a lower altitude.
At high altitude, it can be hard to tell how much fluids you are losing through perspiration as you exercise. Dehydration can also mask other health problems, therefore it is important to stay hydrated. But water can also dilute your sodium levels, so it is also recommended to drink rehydration salts, to ensure that you maintain a healthy hydration balance.
If spending the day at high altitude, it is recommended that you descend to a slightly lower altitude to sleep. The lower oxygen levels at high altitude can reduce the quality of your sleep, but there are also lower levels of carbon dioxide in your blood. Carbon dioxide is involved in your impulse to breathe, so you may experience sleep apnoea (pauses or reduced breathing) when sleeping at high altitude.
Smoking impairs lung function, which can reduce the amount of oxygen you take in at high altitude. Alcohol interferes with the absorption of oxygen by your blood, so that less oxygen may reach your brain. Alcohol may also increase your likelihood of dehydration. Drugs should be avoided, as the effects can vary, but may interfere with your oxygen levels, hydration and overall health.
Carbohydrates are a good source of energy. Unlike sugars, carbohydrates release their energy slowly, helping maintain stable energy levels throughout the day.
Acetazolamide is given to treat and prevent altitude sickness. You should begin taking it 1-2 days before ascending to high altitudes and then continue to take it as you ascend further. Acetazolamide should be used, alongside the guidelines listed above to prevent altitude sickness.
Altitude sickness usually appears within 6-24 hours of reaching high altitude (over 3000m). It can cause headache, nausea, vomiting, dizziness, tiredness, shortness of breath and loss of appetite, with symptoms getting worse at night. If you experience any symptoms of altitude sickness, you should let others know, as your judgement could become impaired as the oxygen is reduced in your brain. Never ignore altitude sickness, as it can lead to critical conditions such as dangerous swelling of the brain or lungs caused by low oxygen levels.
If you get altitude sickness, stop ascending immediately and do not ascend for another 1-2 days, until your symptoms have fully resolved. Ensure that you are staying hydrated and consider taking rehydration salts to maintain your salt level. It is important to rest and avoid alcohol, caffeine and smoking. You could take paracetamol or ibuprofen to treat a headache if you have one, or an anti-sickness medication (promethazine) to treat any nausea. If you do not feel better within 24 hours, descend by at least 500m and wait 2-3 days for your symptoms to resolve until climbing again.