Altitude Sickness
A trekker hit by Altitude Sickness On Hampta Pass Trek

Jascha Heifetz comes to mind ,”There is no top. There are always further heights to reach.” Each year , millions of people travel to dizzying heights in pursuit of adventure , tourism or to compete in various adventure sports like skiing and snow-surfing.

Such trips not only tend to be full of thrilling experiences but also have a great degree of health risks like altitude sickness associated with it. There is also a surprising element of the impact altitude sickness has on different people and in the following analysis , we seek to discuss the various aspects related to the altitude sickness.

What differentiates between the altitude and sea-level ?

Altitude is the vertical distance between a point and the earths surface. The air is comprised of nitrogen(79.04%) and oxygen(20.93%) , which make up the majority of breath every individual takes. This is the composition which will be universally same at any place , be it sea level or high altitude.

Interestingly ,the partial pressure of oxygen in the air , which effectively means how many molecules of oxygen are present in a given volume of air , reduces with increasing altitudes. To cite a 2019 study published in the StatPearls journal , at sea level , the partial pressure of oxygen is 160 mmHg. This figure takes a drastic drop at over 8000m above sea level , where the partial pressure of oxygen plummets to only 53 mmHg (best represented by the summit of Mt. Everest, the highest mountain peak in the world).

The oxygen molecules at such extreme altitudes are farther from each other and not closely packed , as there is NO pressure to push them closer to each other. This signifies that there are fewer molecules of oxygen in the air we breathe and in scientific terminology , we refer to this as ‘hypoxia’.

The partial pressure of oxygen falls by a third as can be seen , which is one of the main reasons for breathing difficulties and disorientation at such heights.

How does the body respond at such high altitudes ?

As soon as the body is exposed to altitude , one starts hyperventilating , which means that one starts to breathe more as the quantity of oxygen in the air reduces and yet with more breathing there is not enough oxygen for the circulatory system and thereby less oxygen supply to the muscles. This impedes the exercise performance.

To add to this scenario , in a couple of hours under this exposure , the water loss from the body also increases , which can lead to dehydration. The downside of altitude is that it can accelerate your metabolism which can kill your desire to eat , which will cause you to eat more than your will to do so to maintain a neutral energy balance.

On an extended exposure to such an environment for days/weeks , the body adjusts to the new environment under a process termed as ‘acclimation’ to the sparse oxygen situation. The increased breathing tendency that was first triggered by the altitude conditions still remains and the hemoglobin levels increase.

Notwithstanding the adaptation of the body at a such a challenging environment , the physical performance will always be mediocre as compared to an equivalent activity at sea level.

Why is it that only certain people are affected by the altitude sickness ?

People who typically undertake an ascent of an high altitude destination , experience the effects of altitude sickness. The most notable symptoms like nausea , headache , dizziness etc. kick in within 6-48 hours of such an exposure. The effect of such symptoms are classically seen in individuals who rush to heights above 2500 meters. This is the reason why hikers and backpackers are abundantly advised to climb slowly especially if they have not had such an exposure before.

It is difficult to make a certain prediction as to who will be affected by altitude exposure as even the fittest of athletes have to face the effects of such an adverse exposure. There are some studies which tend to suggest that people with low ventilatory response to hypoxia are at much risk. This is akin to certain people not being good singers or artists as certain bodies have different coping tendencies for certain environments.

Medical conditions like thalassemia , which hamper the blood’s ability to carry oxygen , also have an impact on the altitude sickness and can complicate the problem. The individuals with a history of such disorders and bad experiences to such exposures are at the highest risk.

Types of Altitude Sickness

1. Acute Mountain Sickness (AMS) : typical symptoms are headaches , nausea , vomiting , fatigue , dizziness ,etc.

2. High-Altitude Cerebral Oedema (HACE) : there is an accumulation of excess fluid and the brain ceases to function normally.

3. High-Altitude Pulmonary Oedema (HAPE) : excess hypoxia can cause leaks , allowing the fluid to enter the lungs.

Studies and their inferences

  • A 2014 National Center for Biotechnology Information study titled “Effects of Living at Higher Altitudes on Mortality” , suggested that people living in higher altitudes had lower mortality from cardiovascular diseases, stroke and certain types of cancer but on the contrast were susceptible to mortality COPD and lower respiratory tract infections. It was suggested that moderate altitudes were most suitable for living in comparison to others.
  • As per a report by Richard A. Lovett , 1 in 4 tourists to the U.S. state of Colorado, for example, gets altitude sickness every year, costing the state about $300 million in lost revenue .

Tips to avoid Altitude Sickness

1. Never Rush

It is advised that those who are climbing great heights , should take it slow and reduce the pace of the ascent. It will help them be comfortable with their trip.

2. Consume Carbs

It has been found that the body requires more energy during the ascent and the changed oxygen levels increase the body’s workload. Consuming carbs like dates , bread , pasta etc. can be of great help during such a journey.

3. Alcohol Is Not Your Friend

Those planning to go for a hike or climbing a mountain , should refrain from consuming alcohol as it can worsen your altitude sickness.

4. Drink Water

It is easy to get dehydrated during such a trip and it is advised to keep drinking water after every gap. It will also keep your morale high and your body fit.

Following the above mentioned tips and going through the aforementioned analysis can keep you in good stead while embarking on a high-altitude journey.

The most important thing to be kept in mind is the weather prediction as well as the instructions issued by your local authorities regarding such a trip.

Having a calm mind is the most integral part of surviving , in the words of Bear Grylls and so should be heeded by one and all.


  1. Happed to me when I was trekking across the Alps. This kind of information should be known before you attempt any trek, Specially at high altitude.


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