As one group of our trekkers summited Mount Rinjani (3726m), another Wildfire Expeditions group is preparing to take on Stok Kangri (6153m). This seems to be the perfect time to cover the basics of acute mountain sickness (“AMS”).
The highest mountain peak in our world is Mount Everest. Standing at 8,850 meters above sea level, it is extreme and difficult for humans to survive. Apart from the visible differences in the terrain and geographic features, the major ‘invisible difference‘ is the effects of altitude on the human body.
We at Wildfire believe that it is the nature of humans to take on challenges and to explore the World beyond these challenges. In doing so, a person has to overcome the harsh and extreme weather, rough and volatile terrain, living and sustaining out of one’s comfort zone, physical demands and the most important of all, understanding the chemistry of high altitude.
What is high altitude?
Alpine climbing involves scaling height and due to the change in atmospheric pressure with altitude ( inversely proportional ), our bodies change as well to deal with the extreme conditions. We need to adapt to the changes in environment physically and mentally within a short time frame to become properly acclimatized to the environment. Studies of high altitude and its effects on the human body have been done extensively to understand the best way of avoiding and managing AMS. This article classifies altitude according to its effects on the human body. The most common classification is –
2500m – 3650m: High Altitude
3650m – 5500m: Very High Altitude
5500m and above: Extremely High Altitude
7920m and above: Death Zone
What are the effects of high altitude?
As we know, atmospheric pressure decreases as altitude increases. The concentration of oxygen at sea level is 21% approximately and the mercuric pressure is approximately 760 mmHg. Our body is well adapted to these conditions. However with increase in altitude, the atmospheric pressure decreases which gives more space for the air molecules to spread wider apart. Even if the concentration of oxygen in the atmosphere remains constant, our oxygen molecule intake per breath decreases.
Our body detects the change and responds to the change by increasing our breathing rate (hypoxia) to meet the oxygen deficiency. We call it ‘breathlessness’ in layman terms. We try to breathe more. To further add complexity, the body increases the Hemoglobin count in our blood which are the oxygen carriers, to hold more oxygen molecules in our blood. This process thickens our blood and hence our heart now needs to pump thicker blood to the extreme organs, which further results in increased pressure on our heart. A slight increase in blood pressure and pulse rate in the high altitude is our body’s reaction to respond to the changed environment.
In order to breathe more oxygen from the air we increase the breathing rate. Excessive hypoxia makes our blood alkaline and our kidneys react immediately by eliminating bicarbonates with the urine to restore the blood pH level. This is why we urinate more in High Altitude.
At around 5000 meters, the pressure is approximately half compared to that at sea level. At the summit of Mt. Everest, it is one-third. Our body cannot handle this deficiency of oxygen in our blood, hence we face several problems which is known as Acute Mountain Sickness ( AMS) or simply Altitude Sickness.
What is Acute Mountain Sickness?
As described above, AMS is caused by our body’s inability or slowness to adapt to the high altitude. Our body, unable to cope up to the harsh conditions, starts to deteriorate and fail. It initially rings the bell by showing various symptoms like headache, dizziness, fatigue, breathlessness, nausea , etc.
Symptoms: headache, dizziness, fatigue, breathlessness, nausea,loss of appetite
Treatment: The body resolves itself after some time spent at that altitude. Mild analgesic or ibuprofen is sometimes taken for headache. Hydration is key. Do not exert physically and rest in camp. Keep an eye on your team member. Restrict further ascent until the symptoms vanish, else descend if symptoms persist. You may put the person n Acetazolomide ( Diamox ) and if symptoms still persist, descent is the only solution. Do not force food. Let hunger come naturally. The most important decision to keep in mind is not to ascend any further until symptoms subside.
How serious can Acute Mountain Sickness be?
Usually, AMS heals on its own with proper acclimatizing. However, further ascent should not be allowed if the symptoms do not resolve. AMS should always be seen as a dangerous alarm for two of the deadliest and fatal conditions at High Altitude – High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE).
If AMS symptoms are not recognized quickly, you might be taking yourself to your death bed high up in the mountains.
What Is High Altitude Pulmonary Edema (HAPE) ?
HAPE is a condition in which the pressure in our pulmonary artery increase so much that it ruptures the week capillaries, especially that of our lungs which is badly Hypoxic. This results in leakage of fluids in our lungs and we have difficulty breathing. HAPE generally happens on the second night, but you should always be on check. Cold conditions increase artery pressure, and increase chances of HAPE.
Symptoms: Breathlessness at rest, fast and shallow breathing, extreme fatigue, cough, sometimes blood in cough, gurgling breaths and dizziness.
Treatments: You cannot treat HAPE at high altitude. The ultimate course of action is immediate evacuation as soon as possible, even during night if required. The symptoms could resolve on the descent, but the team member must be taken to hospital for proper management.
What Is High Altitude Cerebral Edema (HACE) ?
HACE is a condition in which brain functions improperly due to the effects of altitude. The pressure in the cerebral membrane increases and the brain swells. It can be very dangerous and sometimes might not give you time to react.
Symptoms: Loss of cordination ( ataxia), ability to think, change in one’s behavior, aggressiveness, irritated behavior, confusion.
Treatments: Similar to that of HAPE, high altitude is not the place to treat HACE. Only solution is to descend, and your team member show quick signs of recovery on descending good altitude. Medicines like Dexamethasone ( 8mg) can be given, sometimes along with Acetazolomide ( Diamox) to give you time to work out evacuation, if required even at night.
How does the human body adapt to high altitude naturally?
Acclimatization is the process by which our body adapts to these extreme conditions.
Acclimatization is the process in which an individual body copes up and adjusts to the change in its environment. The various factors of the environment change may be chill, heat, altitude, atmospheric pressure, etc. It allows the body to remain normal and maintain performance across a range of environmental conditions.
Acclimatization is a process which takes time depending on the individual. Some people acclimatize more quickly than others. There is no set rule on how long the process should take.. Normally once we enter into the High Altitude Zone (Above 3000 meters) a rule of thumb is to not gain more than 300m a day in elevation from the elevation that you are sleeping. For example if you slept the night before at 3000 meters, you can trek and climb up to 3600 meters during the day, but must come back to 3300 meters to sleep that night. Going higher during the day and trekking back to sleep at a lower altitude is recommended by most professionals.
The 3 main points for proper acclimatization are:
- Climb High, Sleep Low
- Slow Ascent, Do Not Over Exert
- Hydrate, Hydrate and Hydrate
Stay safe and if you feel any of the above symptoms described, tell someone immediately and turn back. Survive to climb another day.