Peruvian Weather and Altitude

May-September is the Andean Winter so going in October means it will still be quite chilly, especially with the high altitude. From what I've read it seems October days have an average of 12.4 hours of daylight and of those 7 are usually sunny with temperatures in the early 20s. However nights will be cold and we have been advised to be prepared for temperatures of minus 10 degrees celsius! I have just bought my thermals and trying them out at home I have come to the conclusion I resemble a bandaged mummy but at least I will be cosy! I got myself a bargain too as M&S were selling them as buy one get one half price and at a much more reasonable price than the outdoor shops! Felt a little embarrassed buying them for the young and attractive guy on the till but what could I do! I am also borrowing my sister's sleeping bag which is designed for freezing temperatures and much better than mine! It'll save me a fortune not having to buy one, so thank you Ruth!

One of the biggest challenges I am going to face in the Andees is the altitude! The higher you get above sea level the more implication this has for the body and the less oxygen is available. At 0m, the standard barometric pressure is 101.325kPa (760 mmHg). This means that there is 100% of the oxygen available at sea level. However, at 4600m, (the highest height I will be trekking to) the standard barometric pressure is 59kPa (441 mmHg). This means that there is only 58% of the oxygen available at sea level!!

I have read a lot about altitude sickness to prepare myself and the good news is that healthy people should be able to travel to altitudes up and above the height of Kilimanjaro (5,895m) as long as they are properly acclimatised. The human body is very adaptive and has the ability to adjust to the changing environment around it and so sufficient acclimatisation will be of great benefit to reduce the possibility of altitude sickness.

That said it is impossible to tell in advance who will be seriously affected by Altitude. The ability to adapt successfully is determined by your genetic-make-up and has little to do with health or fitness. We will all experience some effects of altitude because as we climb we will notice an increase in pulse rate and breathing rate as our bodies work harder to get available oxygen to the muscles but with sufficient acclimatisation, drinking plenty of water and taking our time when trekking we should hopefully all be ok. We will also have a Doctor with us I believe, who will take a reading of our oxygen every morning. Apparently anything under 75 is of concern, not sure what a typical reading is I'm afraid but I will find out.

The common symptoms of Altitude Sickness or AMS as it's otherwise know (Acute Mountain Sickness) are as follows:

• Headache
• Nausea
• Vomiting  
• Fatigue
• Poor appetite  
• Dizziness 
• Sleep disturbance

According to statistics 60% off trekkers ascending heights of 4,500 metres, as we will be, will develop some of these symptoms but they are generally manageable. The effects can definitely be minimised by acclimatising before the main trek and by slow ascents. The occurrence of AMS does not necessarily spell the end of a climb; it does however mean that certain measures should be taken in order to prevent the development of AMS into more serious conditions.

Recommended measures are as follows:

• Sufficient fluid replacement
• The use of Paracetamol/Ibuprofen in order to combat headaches
• The cessation of any further ascent for at least 1 day (or until symptoms are reduced)
• The use of acetazolamide (Diamox)
• If symptoms persist to descend, descend, descend.
• Administration of supplemental oxygen in severe cases 

If AMS is not properly treated and is allowed to develop, more serious conditions may arise. Two such conditions are High Altitude Pulmonary Oedema (HAPE) and High Altitude Cerebral Oedema (HACE), both of which can be life threatening

We will all need to look out for each other on our trip and be honest about how we are feeling and not let pride get in the way. I am going to the Travel Nurse on Thursday to get my booster vaccinations and also Diamox as it is known to reduce the effects of AMS. Charity Challenge advise Diamox is a matter of personal choice and not mandatory as there are also side-effects such as tingling of the fingers and toes but I would rather have it with me in case I feel the need. I plan to take a trial at sea level for a couple of days before we go just to monitor any potential side effects. Best be on the safe side!

I have been ski-ing on a Glacier in Switzerland at 3000m and travelled to the top of the Aguille Du Midi, 3,842m in the French Alps so I feel comfortable I have had some exposure to high altitude before and without ill-effects. Although this cannot guarantee I will not be affected this time, it does calm the nerves a little!

 Sx

Thank you to The Altitude Centre, TM in London for their notes.