One of the main issues with travelling to Cusco is that as its at a high altitude (~3400 metres) it can lead to altitude illness. The most common type of altitude illness is Acute Mountain Sickness (AMS) which occurs in 20-70% of people going to high altitude. The symptoms of AMS are a headache as well as one of the following symptoms: nausea, vomiting, lack of appetite, dizziness or lightheadedness, sleeplessness and fatigue. In our group we have been completing an AMS questionnaire on a daily basis to measure the degree to which people have been developing symptoms associated with AMS. I am one of the people that have experienced symptoms suggesting that I have a poorer tolerance to altitude.
AMS. SpO2. Heart Rate
Day 1 morning. 5. 85. 66
Day 1 evening. 8. - -
Day 2 morning. 3. 85. 69
Day 3 morning. 4. 85. 69
Day 4 morning. 0. 94. 63
Day 5 morning. 0. 95. 72
Day 6 morning. 1. 92. 74
On the first full day in Cusco, even though I had a good long sleep the night before as I hadn't slept much on the plane journeys and I was already showing signs of AMS. I had a moderate headache, which is the main symptom of AMS as well as moderate light headedness. I also had an oxygen saturation of 85%, which was low in comparison with the rest of the group. Throughout the day the headache and dizziness became severe and I put an AMS score in the comments section as I felt it had significantly changed from the morning. The headache was very strong and had similar characteristics to a migraine as I struggled to cope with bright lights, therefore I was instructed to take ibuprofen. This did dull the headache down and allowed me to get a good nights sleep. If this had not improved my symptoms or had i felt as bad in the morning I would have been given Acetazolamide.
The onset of the illness usually in the first three days of reaching high altitude and usually lasts the same period. This is certainly the case with me as my questionnaire scores were greater in the first three days of the trip. In this period I consistently had a headache of a mild or moderate intensity as well as other symptoms. My saturation also stayed low at 85% while my resting heart rate remained relatively consistent. I found that the feeling was very similar to a hangover.
Those at greater risk of AMS are those who make a rapid ascent, people who have had a recent cold and retain fluid at altitude or do not urinate excessively at arrival at high altitude. Due to travelling from Eastbourne at sea level to Cusco this would make it a rapid ascent therefore predisposing people to the illness. Also on the first day I drank 4.5 litres of water, a bottle of coke and a cup of tea but only had five urinations. This suggests that I was retaining my fluids as well as not urinating excessively at arrival. Although i would have had a higher than normal sweat rate due to the excessive heat. I also experienced high altitude oedema in my ankles and lower legs which occurs more frequently in those with AMS.
After the first three days, my oxygen saturation significantly improved as well as my results on the questionnaire. This fits in with the idea that the illness occurs in the first days, after this period the results and my general feelings suggest that I have become acclimatised to the low levels of oxygen so that the necessary amounts of oxygen can be transported to the cells.
We haven't had any members of our group suffer with severe AMS, High Altitude Pulmonary Edema or High Altitude Cerebral Edema. This would be unlikely normally, but more so as our group are specifically measuring responses, very weary of symptoms and have been treating any symptoms early and appropriately. As we have gone past the time when you are most likely to have altitude illness hopefully nobody else will suffer with any altitude illness. We are carrying on the questionnaire and physiological measures to identify any problems that may arise. The next danger point is the increase in altitude along the Inca Trail which goes up to ~4200 metres but hopefully everyone will get through unscathed.