Hiking - Knowledge

Trekking Basics: Defeat the Symptoms Caused By Lack of Oxygen

943 Views - 8 mins read

We all know that the amount of Oxygen decreases as we climb up. This deficiency hampers your body’s functioning, mood, muscles and the entire experience of the trek. To climb a mountain you need a certain level of fitness, but fitness alone does not get you to the top. There are people who have to battle their high altitude sickness and keep in mind the symptoms due to lack of Oxygen. Keeping these two things in mind let us discuss how to combat the deficiency of Oxygen on high altitude places.

Know More Here:

What is High Altitude?

We can define altitude on the following scale:

  • High (8,000 - 12,000) feet
  • Very High (12,000 - 18,000) feet
  • Extremely High, 18,000+ feet

As altitude increases, atmospheric pressure decreases. People with high altitude sickness really find it difficult to cope up with the strenuous activity while climbing up. The symptoms due to lack of Oxygen and the effects of high altitude make it difficult for some people who haven’t been to high altitude places. Another important factor you need to keep in your mind is that with every 1000 feet of elevation gain the air temperature drops about 3.5 degrees. 

high altitude lack of oxygen
High altitude treks have low oxygen levels (source)

Lack of Oxygen- Symptoms and Prevention Methods

As you trek at higher altitude, the oxygen levels drop down which easily effects your body and brain. Let's find out the symptoms due to lack of oxygen and how to prevent it. 

What causes Altitude illness?

This is one of the most frequently asked questions when it comes to trekking at high altitudes. Let us dive deep into this matter. The barometric pressure averages 760 mmHg and concentration of oxygen at sea level is about 21%.  With the increase in altitude, the concentration remains the same but the number of oxygen molecules per breath is reduced. That is why many people suffer from mountain sickness when the climb up during trekking or hiking. 

As one progresses even higher the barometric pressure decreases thereby decreasing the decreasing the percentage of Oxygen molecules per breath. Also due to the high altitude and lower air pressure, there are good chances for the fluid to leak from the capillaries and thereby causing fluid buildup in brain and lungs. 


Acclimatization is one of the effects of high altitude.  We now know what causes the high altitude sickness. Now, it’s time to look at the other ‘lack of Oxygen symptoms’. Continuing to higher altitudes without proper acclimatization can lead to potentially serious illnesses. Generally, the, as the process by which the body adapts to the decrease in Oxygen molecules at a specific altitude. To acclimatize, you need to

  • Climb slowly and steadily.
  • Check yourself every hour. Monitor how you are feeling. Nausea, dizziness, and difficulty in breathing are all warning signs.
  • When you allow your body to operate with a lower percentage of Oxygen, a number of things changes, such as- the body produces more red blood cells to carry oxygen, increase in the depth of respiration.

Symptom #1 Nausea, Dizziness

These are the first symptoms that show your body lacks the right amount of oxygen level. Along with nausea, dizziness you suffer from constant headaches, breathlessness and a complete uneasiness in your entire body. 

Symptom #2 Your Brain Slows Down

It has been well documented that as one climbs higher up a mountain, the amount of Oxygen in the air decreases. As a result, the brain receives less amount of Oxygen and that ultimately results in slowing down. You tend to suffer from nausea, headache and suffer from breathing problems. With these being the primary symptoms to indicate lack of oxygen in our body, let us now see what needs to be done if you encounter these problems.

Instructions do register a tad slower on higher altitudes. Your muscles and nerves all react a tad bit late. The immediate remedy to this danger is to slow down, or even better rest up. This would not only allow your muscles to rest but also allows you to drink some water and stay hydrated. 

Symptom #3 Fatigue Muscles

Fatigue and tired muscles are symptoms caused because of lack of oxygen. Due to low oxygen levels, your muscles tend to tire and thereby the climb becomes a challenging one. No matter how ideal your fitness level is, the low oxygen levels can easily make you take breaks during the trek. 

Preventive Medications

  • Diamox: 

Also known as Acetazolamide, this drug allows you to breathe faster thereby minimizing the lack of Oxygen symptoms. Since it takes some time to have an effect, it is advised to take Diamox 24hours prior to your climb. You must continue for at least five days at higher altitude. There are some side effects associated with Diamox that includes the tingling of the lips and fingertips, blurring of vision, and alteration of taste. In order to reduce the side effects, experts often suggest taking the medicine at a minimum dosage, i.e. 125 mg.

  • Dexamethasone:

It is a prescription drug that decreases the swelling effects of the brain. You are suggested to take a typical low dosage of 4 mg. twice a day for a few days during your ascent. It must be used with caution and only after being monitored by a physician. 

Livingit Tip-
The only difference between these medicines is that Diamox happens to be a drug, whereas Dexamethasone is a steroid.

medicines for altitude sickness
Diamox allows you to breathe faster at high altitude

Prevention of Altitude Illnesses (without medicines)

When you’re dealing with altitude sickness, prevention is the best solution. Keeping your body healthy and energized is also important. One of the preventive measures is to consume at least two bottles of water per day at high altitudes. This will prevent muscle fatigue and your body could use the Oxygen molecules from water. Let us now look at few basic guidelines for proper acclimatization.

  • Stay properly hydrated.
  • If possible, don't fly or drive to high altitude.
  • Eat a high carbohydrate diet while at altitude.
  • Avoid using tobacco, alcohol and other depressant drugs

In addition to these, you must take precautionary actions if you feel dizzy, difficulty in breathing or even if you are coughing up blood while trekking at higher altitudes. These are symptoms of lack of Oxygen in your body that need immediate attention. 

Acute Mountain Sickness (AMS)

To put it in layman’s terms, the Acute Mountain Sickness is the effect of altitude on humans. As we climb higher, the air pressure decreases, which becomes harder for the atmospheric pressure to push in more amount of oxygen into your lungs. This gives rise to malfunctioning of vital organs and other lack of oxygen symptoms in our body. 

There are three stages of AMS

  • mild altitude sickness
  • moderate altitude sickness
  • severe altitude sickness

Some of the AMS symptoms are: -

  • The symptoms of mild AMS include a thumping headache, nausea, fatigue, and lousiness which increase while you are doing strenuous activities on high altitudes. 
  • With moderate AMS, your nausea will lead to vomiting and you will apparently be out of breath, even when doing nothing.
  • Also, AMS will cause disturbed sleep patterns, dizziness, rapid heart rate.
  • The severe forms of AMS are HACE and HAPE (which we will discuss later), which is fatal. 
acute mountain sickness
Acute Mountain Sickness 

Basic Treatment of AMS

It is important for trekkers to control the Acute Mountain Sickness with the following preventive measures on and treatments: -

  • Walking as slowly as possible: You must keep a sensible pace by following the pace of your guide and not jump ahead of the group. The goal is to enjoy the scenery and not to jump ahead of everyone.
  • Decrease your salt intake level, and if you happen to feel a loss of appetite, then avoid eating large meals. Instead, opt for smaller meals for more number of times.
  • Physical fitness: - It has been proven medically that people who have had prior trekking experience have less chance of suffering from altitude sickness. 
  • For Mild AMS: - Rest at the same or lower altitude until the symptoms clear. Consider taking painkillers and anti-vomiting medication.
  • For moderate to severe AMS: - Consider taking oxygen from the can at 2 L/min. Take Diamox at a slightly higher dosage of 250 mg. twice a day.

HAPE - High Altitude Pulmonary Edema

As we have already seen the lack of Oxygen symptoms predominantly includes dizziness, nausea, and difficulty in breathing.  Due to acute altitude sickness, a very serious condition rises, that is the High Altitude Pulmonary Edema (HAPE). It is the accumulation of excess fluids in the lungs. Due to the excess fluid in the lungs, there is a lack of oxygen exchange in the body. It is more likely to occur in people suffering from chest infections and also during cold conditions. One of the important symptoms includes breathlessness. 

Symptoms of HAPE

Listed below are the common symptoms of dreadful HAPE:

  • Loss of physical performance with increased tiredness or fatigue is one of the initial signs of HAPE. 
  • HAPE patients suffer from breathlessness, drowsiness. 
  • The person affected may also cough up watery fluid. 
  • If it gets worse lips, tongue or nails may become blue due to lack of oxygen in the blood.
high altitude pulmonary edema
Excess fluids in the lungs (source)

HACE - High Altitude Cerebral Edema

If you are not taking appropriate actions at the stage of moderate AMS, it can lead to HACE.  It is the result of swelling of brain tissue from fluid leakage. It usually develops over a few days but becomes a life-threatening situation as it progresses. 

Symptoms of HACE

Some of the symptoms of HACE include: -

  • Severe headache
  • Ataxia and clumsiness
  • Disorientation, confusion, irritability, uncooperativeness, poor decision making
  • Paralysis
  • Coma
high altitude cerebral edema symptoms
Severe headaches during HACE (source)

Altitude Training

The best way to train yourself for high altitudes is to prepare your lungs to function even with less oxygen. As with high altitude, it becomes difficult for a first timer to trek efficiently. The best way to do that is to prepare for a trek or just say altitude training. A good altitude training should always include intensive cardio exercises and some moderate strength and flexibility training. Gradually the symptoms due to lack of Oxygen will slowly decrease with more practice.  

The Golden Rules of Altitude Sickness

The three important rules that you must keep in mind when you are trekking at high altitudes are:-

  • If you feel unwell at high altitudes, you may have mountain sickness. 
  • In that condition do not ascend upwards
  • Descend immediately.

Let’s Sum it Up!

Trekking really has grown as an interesting hobby for the youth nowadays. In order to trek efficiently and without stopping you need to check if you have any symptoms due to lack of Oxygen showing in your body. The real fun of trekking comes at higher altitudes and you need to take the proper medication if you are suffering from mountain sickness. Medication, cardio exercises and proper rest are the vital points to keep in mind when you are trekking at high altitudes.

Cover Source