General Information

Many people succumb to the effects of the high altitude and acclimatisation and do not reach the summit, but the latest statistics show more reach the summit than do not.

The effect of altitude can start to be felt at around 3,000 - 3,500 metres above sea level - though everyone is affected differently, some people are absolutely fine and others could experience strong symptoms of acute mountain sickness at less than 3,000 metres.  Around this height the air is 'thin' enough through reduced oxygen to make our oxygen intake per breath markedly lower, so we can start to feel the symptoms of altitude.  At 3,500 metres the barometric pressure is roughly a third less than at sea level though the oxygen levels in the air are the same (as sea level), but the lower pressure reduces the amount of oxygen we are breathing in.  This means there is less oxygen circulating in our blood, making our bodies breathe faster to try and compensate.  We cannot breathe enough oxygen in to return our oxygen levels to that of sea level, so our bodies adjust to compensate for this.

This adjustment is our bodies' acclimatising and is very important for climbing at altitude as it allows us to function using less oxygen.  To do this our body creates more red blood cells, which it needs to help carry more oxygen.

How people acclimatise varies from person to person.  Some will not feel any different after ascending during the day and others will gradually get a headache (a common symptom of altitude) as they climb then after some rest and plenty of fluids feel fine again.  There is a greater risk of altitude sickness if you ascend too quickly because your body needs time to adjust to different oxygen levels so we walk 'pole-pole' (swahili for 'slowly slowly') when ascending.  There is a drug available called Diamox that helps with the symptoms of altitude, and we have information about this on the Vaccinations and Health page.

Our treks have an extra day built into them to aid acclimatising and ascending Mt Meru or Mt Kenya before Kilimanjaro really helps with altitude problems.  Doing this allows your body to acclimatise to the highest point you have reached, making reaching this height again much easier and giving your bodies the chance to adapt to the reduced amount of oxygen.

Your fluid intake should be high when climbing at altitude, as it is easy to get dehydrated which will affect your performance and enjoyment of the trek.  Staying properly hydrated is very important for combating the effects of altitude; headaches are a symptom of mountain sickness and an unpleasant condition but can be kept to a minimum by drinking enough water.  You should aim for copious, clear coloured urine - water retention can be a sign of the body not acclimatising.  So, it is important at altitude to pay attention to urine output, how you are feeling and keeping your guide informed.

Just about everyone that goes to altitude will feel some sort of Mountain Sickness during a climb, the usual symptoms are headaches, feeling dizzy, short of breath, fatigue and nausea.   These are not necessarily anything to worry about, as long as hydration levels are kept up they should dissipate and go again after a rest: inform your guide and ask for advice as often an aspirin can be taken to help get rid of these symptoms.  There are certain things you can do to try and avoid the effects - don't consume caffeine or alcohol, avoid tobacco and try not to over exert.  Keep your guide informed and they can just keep an eye on you and offer advice if they persist.

Many people experience symptoms of Acute Mountain Sickness (AMS) as their bodies acclimatise to the difference in height as they climb - the majority of people in the UK live between 100 and 600 metres above sea level where the air is rich in oxygen, so climbing to where the air is markedly thinner is bound to have an effect.  The symptoms of AMS are basically the same as mountain sickness, but often appearing together and being much stronger (a pounding headache and feeling very tired etc).

It is important to convey how you feel to your guides as they have a lot of experience of AMS and can talk you through how you feel, and how long you have felt this way etc.  It can be quite unpleasant at the time but it is still not necessarily anything to worry about: if you ensure you are properly hydrated and have some good rest, the symptoms should clear up overnight as you rest at that height.

However, you must pay close attention to the symptoms and if they persist or get worse, make sure the guide knows.  Symptoms of Acute Mountain Sickness can develop into two potentially fatal conditions if the climber ignores them and keeps ascending.  Descent is the cure for AMS if it does not get better, as there is no point in carrying on if you feel bad.  The summit of a mountain out of reach is not worth endangering one's health, and by climbing when your body is telling you to stop is certainly not the best thing to do.

In severe cases when trekkers let the symptoms become serious, an assisted fast descent is required, but this is very rarely needed.  Recovery generally comes remarkably quickly once lower altitudes are reached.

Ignoring the symptoms of AMS and still ascending can lead to developing potentially fatal conditions; these are High Altitude Pulmonary Oedema (fluid on the lungs) and High Altitude Cerebral Oedema (fluid on the brain).  These are both extremely serious conditions that require medical treatment.  Only 2% of people with AMS develop these conditions, but with communication between trekker and guide, AMS should never become anything more serious than a severe headache or the other common symptoms.

For further information, Medical Expeditions (Medex) produce a very detailed booklet "Travel at High Altitude", endorsed by the British Mountaineering Council, which can be downloaded free from www.medex.org.uk.