High Altitude Health Tips

The mountains are among the most beautiful places to visit, and we hope to enjoy every bit of the visit. However, these mountains often rest at high elevated grounds and can cause health problems for visitors like you and me – the hikers, trekkers, and climbers.
Here, we will discuss the health issues at high altitude and the common injuries that are likely to hit us. We will also share some tips on how to prevent these injuries, as we all know that prevention is always better than cure.


Health Issues at High Altitude

Altitudes over 3,000 meters can pose some health issues. Not only will our body have to cope with the sudden increase in altitude, it becomes more susceptible to common ailments such as dry cough and flu due to the colder weather. Though generally not life-threatening, these health issues can drastically alter the level of performance during a trek. It is vital and important to look after the body well and keep it in optimal conditions at altitude.


Some of the most common effects of altitude exposure on the human body include:

Reduced physical performance: The human body cannot maintain the same physical performance at altitude as they can at sea level, regardless of the fitness level.

Psychological Effects: Altitude exposure may result in changes in senses (e.g., vision, taste), mood, and personality. These effects are directly related to altitude and are common at over 3000m. Some effects occur early and are temporary while others may persist after acclimatization or even for a period of time after descent.

Sleep Disturbances: Altitude exposure may have significant effects on sleep. The most prominent effects are frequent periods of apnea (a temporary pause in breathing) and fragmented sleep. Reports of “not being able to sleep” and “being awake half the night” are common and may also contribute to mood changes and daytime drowsiness or even dryness in the throat.

Dehydration: Dehydration is a very common condition. Causes include perspiration/sweating, vomiting, increased breathing, and diminished thirst sensation. Dehydration decreases physical performance, increases symptoms of altitude illness, and may increase risk of developing cold injuries.

Nutrition: Poor nutrition can severely impact the health and contribute to illness or injury, decreased performance and poor morale. At high elevations dulled taste sensations (making food undesirable), nausea, or lack of energy can decrease the motivation to prepare or eat meals. Poor eating habits may also lead to constipation, aggravation of hemorrhoids, and undesired weight loss.


These Are Some Ways That You Can Take Care Of Your Health At Altitude:

Acclimatization: If you notice any early-warning symptoms (headache, nausea, sleeping problems, dizziness, general uneasiness), do not ascend to a higher altitude. Consider asking your GP about medicines such as Diamox (acetazolamide) before the trip. Diamox is not recommended for treks below 5,000 meters.


Hydration: Dehydration at high altitudes can be a serious problem, especially while you are acclimatising. Do not assume that you are OK if you are not thirsty. Drink water or tea regularly and aim for at least 2-3 litres of liquids each day. Start hydrating adequately a few days prior to the start of the trek and throughout the trek.

Keep warm / Stay dry: Extremes of temperature are not uncommon. The temperature can rise or fall in a very short space of time. Ensure that you have the essential layers of warm clothing to prevent the body from catching a chill. Trekking in the day can be hot and causes the body to perspire. It is important to avoid wearing clothes made from fabric that does not have high absorbent rate for moisture or has poor wicking property such as cotton and wool to keep the body dry.

Booze up the immune system: Take multi-vitamins or Vitamin C, eat lots of fruits and vegetables if possible.

Keep the throat moist: Due to the dry and cold air, dry throat and cough is common at altitude. Keep the throat moist by drinking warm water (good to drink honey lemon water), taking 1 or 2 lozenges daily and breathe through the nose to reduce taking in a larger amount of cold, dry air with every breath. Keep a small thermal flask with hot water with you at bedtime such that warm water is within reach if you wake up with a dry throat in the middle of the night.

Eat well: You will need those extra calories to keep warm and give you the energy for the long treks.

Avoid Alcohol and sleeping agents (medication that cause drowsiness): Avoid use of alcohol or sleeping agents. They both suppress breathing and result in lower blood oxygen level in the body.

Get adequate sleep & rest: It is sometimes difficult to sleep at high altitude, try to avoid lying flat on the bed or in a tent. Use your backpack as a back rest so that you rest your upper body slightly elevated.


Understanding the health issues at high altitude, we list the three potential injuries:

1. Altitude Sickness
2. Sun Damage
3. Cold Injuries


As one ascends through the atmosphere, barometric pressure decreases (though the air still contains 21% oxygen) and thus every breath contains fewer and fewer molecules of oxygen. One must work harder to obtain oxygen, by breathing faster and deeper.

Mountain medicine recognizes three altitude regions that reflect the lowered amount of oxygen in the atmosphere:

  • High altitude = 1,500–3,500 metres
  • Very high altitude = 3,500–5,500 metres
  • Extreme altitude = above 5,500 metres

Travel to each of these altitude regions can lead to medical problems, from the mild symptoms of acute mountain sickness to the potentially fatal high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). The higher the altitude, the greater the risks. Research also indicates elevated risk of permanent brain damage in people climbing to extreme altitudes.

Let us understand the various symptoms of altitude sickness.

1. Acute Mountain Sickness (AMS)
Acute mountain sickness (AMS) is the most common unhealthy response to altitude: it is a collection of signs that your body is becoming ill and has not adapted successfully to a higher altitude.

For your own safety, assume any illness at altitude is AMS. The most common reasons that people fail to descend as soon as they should are bad assumptions. They assume that having AMS is a sign of weakness; that their level of fitness means they should not have AMS; or mistook their symptoms for flu or another illness. Assume AMS first: it happens to healthy strong people, and if it turns out you are indeed sick with something else, descending to a lower altitude will make it easier for your body to heal anyway.

In particular, if you have recently ascended, and you have a headache and any other symptom, you have AMS. The other signs of AMS vary for different people, but include:

  • fatigue
  • dizziness
  • loss of appetite
  • nausea or vomiting
  • confusion
  • difficulty walking (called ataxia gait)
  • rattling breath
  • feeling generally extremely ill

The last three signs in particular are signs that you are becoming quite ill. You should not wait for the onset of these symptoms before acknowledging you have AMS. They are fairly reliable indicators of the onset of HACE or HAPE.

You and your party should keep an eye on each other for signs of AMS. If you suspect of someone suffering from AMS, look out for signs of it worsening. Very sick people can become confused and not realise how sick they are. Loss of appetite is a particularly good sign: anyone who has been walking or climbing at altitude for a day should be hungry for a good meal in the evening.


2. High Altitude Cerebral Edema (HACE)Brain Pic by Joanne (resized)
High altitude cerebral edema (HACE) is the end-stage of AMS (conversely AMS can be thought of as the mild form of HACE). When you suffer “HACE”, your brain swells and stops working properly.

HACE symptoms include a number of signs of failing mental function: confusion, fatigue and unusual behaviour. But the most reliable one is ataxia gait, and you can test it by walking heel to toe along a straight line on the ground. Healthy people can pass this test easily; anyone who has difficulty balancing while they do it may be showing signs of HACE.

HACE is extremely serious, and you may only have a few hours to help someone with HACE. The most important treatment for this is immediate descent, but a person experiencing these symptoms will need significant help. Dexamethasone is one drug that can be used to relieve symptoms, but it is just a temporary bridge to give more time for descent.


3. High Altitude Pulmonary Edema (HAPE)
High altitude pulmonary edema (HAPE) is another severe altitude illness. It sometimes occurs in Lung Pic by Joanneconjunction with AMS or HACE, but sometimes not — it is thought to have different causes. When you have HAPE, your lungs fill with fluid. Signs include extreme fatigue; breathlessness (when not due to interrupted breathing — give yourself 30 seconds to recover upon waking); cough especially if it is wet and has blood in it; rattling or gurgling breath; chest congestion; very fast heart rate; very fast breathing; and blue extremities. A fever is sometimes present. It most commonly sets in at night.

Preexisting Medical Conditions
People with preexisting medical conditions should speak with a doctor before travelling to high altitudes:

  • Before their trip, people with heart or lung disease should talk to a doctor who is familiar with high-altitude medicine.
  • People with diabetes need to be aware that complications of diabetes may be triggered by altitude illness and may be hard to treat if they are taking medicine for altitude illness.
  • Pregnant women can make brief trips to high altitudes, but they should talk to their doctor because some doctors recommend that pregnant women not sleep at altitudes above 3,500m

Preventive Measures for Altitude Sickness
These are things that you can do to improve your chances of not getting altitude illness:


  • Hydrate your body, drink regularly
  • Have sufficient rest; do not over work your body before you leave for your trip
  • Eat well

During Trip

  • Ascend gradually
  • Hydrate adequately. Drink plenty of fluids and remember to pee too
  • Avoid alcohol, smoking, and caffeine
  • Do not take sleeping agents or any medication that cause drowsiness
  • Eat regular meals, high in carbohydrates.
  • Climb high; sleep low whenever possible
  • Try not to ascend more than 800m in a single day at altitude above 3,500m whenever possible
  • Learn how to recognize early symptoms of mountain sickness

Golden Rules that can help you to avoid getting into a severe confrontation with death!

Golden Rule #1
If you feel unwell at altitude, it is altitude illness unless proven otherwise!

Golden Rule #2
Never ascend with symptoms of AMS

Golden Rule #3
If you are getting worse (or have HACE or HAPE), go down at once!



Lee Peh Gee on Everest

An example of a sun burn caused by cold strong wind

At high altitude, the ultraviolet rays from the sun are more intense and therefore more damaging. Even when it is cloudy, the risk of sunburn is extreme. The main reason for this is that in cool or cloudy conditions many people are unaware that they are still vulnerable to the burning effects of the sun’s UV radiation, so fail to take precautionary sun protection measures.

There is also a risk of wind contributing to a burn, though the wind does not really burn you.  The cooling effects of the wind decrease the perception of heat and burning. In other words, individuals are less likely to seek shade or to protect themselves against the sun, and are more likely to stay exposed to the burning effects of the sun’s UV radiation for longer. Along with being cooling, the wind also has a drying effect on the skin, which may exacerbate the symptoms of sunburn.

Scientists found that human eyes were more likely to be damaged by UV rays while skiing or climbing on the slopes in snow-covered areas compared to sitting on the beach. With exposure to high levels of UV more harmful to eyes than skin, especially in snow-covered areas, the rays can cause conditions such as snow blindness, which can lead to inflammation, cataracts and clouded lenses.

The safest way to enjoy the sun and protect you from sunburn is to use a combination of shade, clothing, and sunscreen.

A combination of protection from the UVA

A combination of protection from the UVA

  • Use a sunscreen of at least SPF15 which also has high UVA protection.
  • Ensure sunscreens are applied generously to all exposed skin areas.
  • Apply sunscreen 20 – 30mins before sun exposure and re-apply every two hours.
  • Remember to lube up your lips too, with an SPF lip moisturiser. Re-apply regularly.
  • Cover up using clothing such as wide brimmed hat and long-sleeved tops, closed-weaved fabrics may offer better sun protection.
  • Seek shelter or shade whenever possible.
  • Protect your eyes from sun exposure by using sport shades with UV protection, wrap-around sunglasses or close-fitting sunglasses with wide lenses that protect your eyes from every angle. When strong wind is imminent, wear a goggle.



Exposure to cold can produce a variety of injuries that occur as a result of man’s inability to adapt to cold. Therefore, trekking and climbing in cold climates face many risks.

Cold Injuries

Common injury to the fingers due to long exposure in cold environment with little or no protection

Cold injuries are usually due to prolonged exposure to cold temperatures, although they can occur with brief exposure to extremely cold conditions. For heat regulation, our body uses its core (internal organs such as the brain and heart) and its shell (skin, muscles, and limbs). Cold injury to our body’s core is called hypothermia, and cold injury to our body’s shell is called frostbite. Hypothermia and frostbite commonly occur together, but they can occur separately.

What is Hypothermia?
Hypothermia is a decrease in core body temperature from exposure to a cold environment. Surprisingly, hypothermia can even occur at mild temperatures if exposure is prolonged. Our body’s natural defenses against the cold are quite limited. Initially, the blood vessels in our skin constrict to reduce heat loss and to keep blood flowing to the vital organs. Shivering (involuntary muscle contraction) and the increased release of hormones result in increased heat production. However, blood vessel constriction and hormone release are usually inadequate to maintain our body’s temperature in cold environments. Individuals who drink alcohol, as well as those who suffer from fatigue, spinal cord injuries, or poor nutrition, are at greater risk for hypothermia.

What is Frostbite?
Frostbite is a localized cold injury to a body part that may occur with or without hypothermia. It is most likely to happen in body parts farthest from the heart and those with large exposed areas. Body parts such as the feet and toes, the hands and fingers, ear, nose are areas that are highly likely to be frostbitten in extreme situations. In some instances, tissue damage is so extensive it may require amputation. When human tissue is exposed to near-freezing temperatures, the tissue temperature decreases. As the tissue temperature decreases, it goes through four phases of frostbite. In the first phase, the blood vessels constrict, causing inadequate blood flow and oxygen delivery to the tissues. In the second phase, the tissue temperature drops below sub-zero degree, and ice crystals form in the tissues. Unless the body part is re-warmed, frostbite will progress to the third and fourth phases. In the third phase, fluid leaks from the blood vessels into the damaged tissue. In the fourth phase, the blood vessels clot, resulting in irreversible loss of blood flow to the damaged tissue.

Frostbite symptoms typically start with a sensation of extreme coldness, followed by numbness, and then clumsiness. Superficial frostbite results in numbness and the development of clear, fluid-filled blisters. Deeper frostbite causes deeper blisters filled with purplish fluid. In all types of frostbite, the damaged tissue may swell and darken in color after re-warming.

What is Frostnip?
Frostnip is a superficial cooling of tissues without cellular destruction. The initial stages of frostbite are sometimes called frostnip.

How to prevent cold injuries
First, let’s understand what causes cold injuries such as hypothermia and frostbite. Inadequate blood circulation when the ambient temperature is below freezing point leads to frostbite. This can be because the body is constricting circulation to extremities on its own to preserve core temperature and fight hypothermia. In this scenario, the same factors that can lead to hypothermia (extreme cold, inadequate clothing, wet clothes, wind chill) can contribute to frostbite. Poor circulation can also be caused by other factors such as tight clothing or boots, cramped positions, fatigue, certain medications, smoking, alcohol use, or diseases that affect the blood vessels, such as diabetes.

Modern clothing and equipment have decreased the risk for mountain climbers, but frostbite still occurs after accidents, as a result of poor planning, and in severe, unexpected weather. To prevent hypothermia and frostbite in cold conditions, be sure to change out of wet garments promptly and drink plenty of fluids to avoid dehydration. Here are some pointers to note:

  • Wear layered clothing to create insulation
  • Plan for additional warm clothing to change out wet ones, this includes gloves and socks
  • Wear layered gloves; one single thick glove does not have sufficient insulation
  • In extreme altitude, you will need to wear layered socks to climb
  • Wear only waterproof trekking/climbing shoes or boots
  • Trekking/climbing shoes or boots must have room for layered socks
  • Be diligent to stick to a proper acclimatization plan
  • Stay hydrated; avoid alcoholic drinks and smoking
  • Wiggle your fingers and toes regularly as you move to improve blood circulation
  • Apply moisturizer to your fingers and toes to prevent chapped skin

You can click here to read more about the layering concept for attire.



  1. International Society for Mountain Medicine – [ISMM]
  2. Cold Injuries: Hypothermia and Frostbite [CDC]