After flying into Lukla the rest of our journey to the fieldwork site is on foot, from Lukla to our lodge in Tangnak it is around 45 km but we take our time to make sure we acclimatise to the increase in elevation. Lukla is at an elevation of 2840 m and already you can feel the difference. We will eventually be working at an elevation of 4600 m, at this elevation many people will develop altitude sickness without proper acclimatisation. This is especially important as we will be working this altitude for almost 2 months need to be as fit and healthy as possible.
As you go up in elevation the air pressure decreases so that even though there is still the same percentage of oxygen in the air, each breath you take contains fewer oxygen molecules. People feel the effects of altitude from around 2000 m but most can travel to 2400 m without difficulty. By 3600 m there are 40% fewer oxygen molecules than at sea level. To combat this your body makes you breathe deeper and faster, and your heart rate and blood pressure will increase so that you get the oxygen you need to your brain and other organs. Overtime the body begins to adapt to the change in air pressure and produces additional red blood cells and capillaries and uses a greater portion of your lungs than usual. Even when your body adapts or acclimatises to the increase in altitude you still won’t get as much oxygen as you would at sea level. As a result you won’t be as fit as you are at sea level, strenuous exercise can still be difficult and you might find your memory isn’t as good as usual. Giving our bodies time to acclimatise is not only important to be able to work on the glacier but also to prevent altitude sickness.
Altitude sickness occurs when you when you travel to higher altitudes too quickly and don’t get enough oxygen. Mild symptoms can include headaches, loss of appetite, sickness, poor sleep, weakness and dizziness . However, there is also a risk of potentially fatal high altitude pulmonary or cerebral oedema. Altitude not only affects everybody differently but each time you travel to high altitude your own body can respond differently. It is always important to allow enough time for acclimatisation and to listen to your body. There are three golden rules;
- If you feel unwell you have altitude sickness until proven otherwise.
- If you have symptoms of altitude sickness do not ascend any higher.
- If you are getting worse or not improving decent to a lower altitude.
The best plan is always to acclimatise as well as possible, everyone is different but there are a few simple steps that we follow.
- Ascend slowly – you should aim to ascent not more that 3-400 m each day and rest every 3rd day (or 1000 m).
- Climb high, sleep low – always try to sleep at a lower elevation than the highest point that day.
- Drink plenty of water – being dehydrated reduces your ability to acclimatise and the air at altitude is often dry so you need to drink a lot more than you would at home, aim for 4 + litres.
- Take it easy – being exhausted can also reduce acclimatisation, make sure you take it a bit easier and try to eat properly.
There is a lot of information about acclimatising and altitude sickness, including the following links;