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Climbing Kilimanjaro

What is Acute Mountain Sickness (AMS)?

Acute Mountain Sickness (AMS)

Usually the air that is surrounding us consits of 80% carbodioxid and 20% oxygen. As these 20% of oxygen is the ideal concentration for the human body and the maximum concentration that can be found, it is also been said to be 100% oxygen concentration. This concentration is necessary for our muscles and our brain to work. The more you climb to higher altitude levels, the less oxygen concentration you will find due to the decereasing air pressure. At 1500m (5,000ft) above sea level the oxygen concentration drops to 85%. So what happens inside your body is that your blood cells can no longer carry enough oxygen to provide it to your muscles. Therefore you will start to feel tired and you have to breathe more, to compensate the lack of oxygen. This effect will become stronger the higher you ascend to the mountain.

What is Acute Mountain Sickness (AMS)?

The good news is: Our body can adapt to a lower oxygen concentration by producing more red blood cells. This process is known as acclimatization.
The bad news is: Adapting to lower oxygen concentration takes time, and every person reacts differently.

PLEASE NOTE: This is not related to your fitness level. In fact, a person with a very high fitness level can suffer very strong from the lack of oxygen.

After reaching 2.500m (8,200ft) things are getting more serious. The oxygen levels goes down to about 75%. This is where altitude sickness might start as a lower oxygen concentration is affecting your muscles, your inner organs and even your brain. It starts slowly by having a headache, losing appetite, slight insomnia but can become really serious and even lead to death at extreme altitude above 4.500m (15,000ft). That’s why we highly recommend to choose a route with sufficient days to give your body enough time to adapt to new oxygen levels. The main cause of altitude sickness is going too high (altitude) too quickly (rate of ascent). It is very important to get enough sleep, to eat well (even if you don’t feel hungry) and to drink enough water to have the energy that you need to recover and to prevent dehydration.

Mountain medicine recognizes three altitude categories:
  • High altitude: 1.500m to 3.500m (4,900ft to 11,500ft)

  • Very high altitude: 3.500m to 5.500m (11,500ft to 18,000ft)

  • Extreme altitude: 5,500m and above (18,000ft and above)
    Uhuru Peak stands at 5.985m (19,340ft)

At over 3.000m (10,000ft), more than 75% of climbers will experience at least some form of mild AMS.

Our guides will monitor your condition during the entire climb but you should communicate any kind of symptoms immediately. Therefore it is good to pay attention to first signs of Altitude Mountain Sickness (AMS).

There are 3 categories of Acute Mountain Sickness with different symptoms:
  • Mild AMS
    Headache, Nausea & Dizziness, Loss of appetite, Fatigue, Shortness of breath, Disturbed sleep

  • Moderate AMS
    Severe headache (that is not relieved by medication), Nausea and vomiting, increasing weakness and fatigue, Shortness of breath, Decreased coordination (ataxia)

  • Severe AMS
    Shortness of breath (also while resting), Inability to walk, Decreasing mental status, Fluid build-up in the lungs (High Altitude Pulmonary Edema), Swelling of the brain tissue (High Altitude Cerebral Edema)

Acclimatization Guidelines:
  • The following are recommended to achieving acclimatization:

  • Pre-acclimatize prior to your trip by hiking at high altitude if possible.

  • Ascend Slowly. Your guides will tell you, “Pole, pole” (slowly, slowly) throughout your climb. Because it takes time to acclimatize, your ascension should be slow. Taking rest days will help. Taking a day increases your chances of getting to the top by up to 30% and increases your chances of actually getting some enjoyment out of the experience by much more than that.

  • Do not overexert yourself while climbing and only according to the advice of your guides.

  • Take slow deliberate deep breaths.

  • Eat enough food and drink enough water while on your climb. It is recommended that you drink from four to five liters of fluid per day. Also, eat a high calorie diet while at altitude, even if you don’t feel hungry.

  • You can use Diamox to prevent mild symptoms of AMS. Please note that you should talk about Diamox to your doctor prior to your climb. It is rarely available in Tanzania and Tanzania Horizon Safaris is not promoting or selling Diamox.

  • Avoid tobacco, alcohol and other depressant drugs including, barbiturates, tranquillizers, sleeping pills and opiates. These further decrease the respiratory drive during sleep resulting in a worsening of altitude sickness.

  • If you begin to show symptoms of moderate altitude sickness, don’t go higher until symptoms decrease. If symptoms increase, descend.

Altitude Medication

Diamox is an approved medication for the prevention and treatment of mild AMS. The medication acidifies the blood, which causes an increase in respiration, thus accelerating acclimatization.

Diamox cannot treat heavy symptoms of altitude sickness, but it can help to prevent it. If taken properly Diamox is reported to lower/prevent severe symptoms of Acute Mountain Sickness (AMS).

The medicine should be continued until you are below an altitude of 2.500m. Side effects of Diamox can be tingling or numbness in your fingers, toes and face, taste alterations, excessive urination and blurring of vision. Side effects usually go away when medication is stopped. It is a personal choice of each climber whether or not to take Diamox as a preventative measure against AMS.

Tanzania Horizon Safaris neither advocates nor discourages the use of Diamox!
Ibuprofen or IbuTad can be used to relieve altitude induced headaches.

Emergency Oxygen & Mountain Rescue

We carry bottled oxygen on all of our climbs as a precaution and additional safety measure. The oxygen cannister is for use only in emergency situations. It is NOT used to assist clients who have not adequately acclimatized on their own to climb higher. The most immediate treatment for moderate and serious altitude sickness is descent. With Kilimanjaro’s routes, it is always possible to descend, and descend quickly. Therefore, oxygen is used strictly to treat a stricken climber, when necessary, in conjunction with descent, to treat those with moderate and severe altitude sickness.

We are aware that some operators market the use of supplementary personal oxygen systems as a means to eliminate the symptoms of AMS. To administer oxygen in this manner and for this purpose is dangerous because it is a temporary treatment of altitude sickness. Upon the cessation of the use of oxygen, the client will be at an even higher altitude without proper acclimatization.

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