Altitude Illness - Self Report

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.

James

Testing Week Two

Heat Acclimation Overload

Another week of testing with the start of the heat acclimation process for one third of the students on the project. The heat acclimation training requires 10 days of 90mins cycling at 50%VO2max in 40 degrees Celsius. Measures of heart rate, rating of perceived exertion, thermal sensation, core temperature and physiological strain are taken every 5th minute for all participants.

The other two thirds of the group are either completing a normothermic training for the same duration and intensity, or no training at all. The students in the control doing no training at all are acting as the experimenters and busy collecting all the data from the 16 exercising participants.

Needless to say, the heat acclimation hasn't been easy, but the 8 students completing the training have worked hard so far, especially considering this has had to be done around their normal students and the considerable amount of work that is due in soon or immediately after Peru.

In the week prior, participants had completed VO2max tests and heat tolerance tests in which they run until exhaustion in the 40C environment. All participants will complete these tests again after 5 and 10 training sessions.

Participants are also required to give venous blood samples at the same time points. This is to measure various blood markers including heat shock protein 72, a protein chaperone known to be up-regulated when the body is subjected to sufficient environmental and physical strain. It is suggested that by up-regulating HSP72 an individual may improve their tolerance to environmental extremes such as heat and altitude.

Oli Gibson, who is leading this research project, is now looking rather more stressed than normal, as the snow day and closure of the University has caused all sorts of problems with rearranging of testing, lectures and bookings for the chamber. Fortunately it all seems to be going well, follow our twitter page to follow how it goes.

Testing Week One

Labs looking relatively clear before the enslaught

Week One - TICK

So at the end of week one of four, we have been successful in completing all 29 VO2max tests, 29 Heat Tolerance Tests, 174 normoxic and hypoxic walking tests and 29 hydration tests. Not bad at all.

Alice M, James and Ben D completing an outdoor walking test

Lee doing his hypoxic walking test

6MWTs

Of all the tests the 6min walking test has been the most surprising in that it is deceptively painful on the lower leg muscles, yet it also very repeatable. Time and statistical analysis will tell but the immediate response is that many people across hypoxia, normoxia and outdoor got very similar and representative distance and physiological results. 

Ben P completing his first heat tolerance test

Dominic looking he is enjoying the 40C

Tess completing her VO2max test using the Cortex Medical Metalyser

VO2max

Oli has been busy conducting all 29 VO2max trials on the cycle ergometers and using the Cortex Medical Metalyser, which has worked really well and calibrated first time every time, especially considering the number of tests completed on the one machine in one week. 

Ben's study on fat metabolism at altitude, which starts in two weeks time, will be using the Cortex Medical Metamax 3X for  

Although it has been busy and a little hectic at times, I believe everyone has enjoyed it. From a staff perspective it seems like it has brought all the students and staff together in the realisation that we are all in this together. Of course this research is all in addition to normal workloads of both the staff and students so working round lectures and meetings has been interesting at times.

For updates on the testing and some excellent pictures of very sweaty individuals please follow our Twitter page @UOB_PERU2013

Research

Undergraduate students undetaking incremental VO2 max tests
using the Metamax 3X System  from Cortex Medical

Testing Times

So with 1 month to go, the sea level testing is due to start. Ambitiously we are trying to fit in five reasonably large research projects over the Peru project to gain as much from the opportunity as possible. Suddenly the  realisation of what we are undertaking and how much that involves when considering a sample size of 29 becomes apparent on making all the sign up sheets for all the testing slots. However, most seem to be up for the challenge and realise the learning opportunity that it obviously brings.

The Hypoxic Chamber (Altitude Centre, London)

To give you an idea of numbers, simply before we go to Peru we need to complete:

- 24 Incremental VO2max Tests 

- 10 Lipid Challenge Tests

- 10 Basal Metabolic Rate Tests

- 58 Tests of Hydration

- 58 Hypoxic Walking Tests

- 72 Heat Tolerance Tests

- 87 Normoxic Walking Tests

- 261 Venous Blood Samples 

- 80 90min Heat Training Sessions

- 80 90min Normothermic Training Sessions 

= ~540 hours of testing.

To make sure all participants are booked in and appropriately prepared for testing we have created eight separate booking sheets to sign up for testing online. While all students have chosen one of the four physiological research studies to be experimenters for during sea level testing and while in Peru.

Our Gantt chart overview of testing blocks

Dr Alan Richardson and Dr Peter Watt analysing some blood samples

This amount of testing will obviously be a challenge and something I for one am looking forward to. We should be able to answer some really interesting questions, while offering our undergraduate and post- graduate students the opportunity to undertake some excellent projects and get even greater experience of laboratory techniques. 

Over the next few weeks we will be showing you the testing we are undertaking prior to leaving for Peru. We will be taking photos and making films.

Testing starts on Monday!

Para-monte: Altitude illness awareness charity

Some of you reading this may well have heard the tragic story of the Eastbourne resident Adam Savory dying of altitude illness in Cusco Peru in September 2012. This was recently reported in the Eastbourne Herald on 25th January 2013. News Article

Within the report you will find the family and friends are working hard to develop a charity, Para-monte, to raise awareness of altitude illnesses and the methods to recognise symptoms and what to do if they occur. This charity will offer such an important information source for people travelling to altitude.



All individuals doing the Peru project offer their deepest sympathies with the family and friends of Adam and will help in whatever way we can to spread the word of Para-monte and altitude illness awareness, to reduce the chance of others in the future suffering the same.

We also hope that the research being undertaken here will help towards the understanding of altitude illnesses and the sea level prediction of if.

High altitude health advice

High Altitude Health Advice

Typically mountaineers ascend from low to higher altitudes and are thus exposed to continuously increasing hypoxia. As the altitude increases, the barometric pressure within the surrounding environment falls. This drop in barometric pressure, and thus drop in the density of the air means that there are fewer oxygen molecules in a given volume of air than there are at sea level. Therefore with each breath, less oxygen is able to be taken in and utilised by the body. This subsequent reduction in oxygen delivery coupled with various other confounding factors can therefore induce health issues for an individual at altitude.

This page will identify the health issues that are likely to arise on a trip to high altitude (above 2,500m) and provide advice as to how these conditions may be prevented and/or treated in order to maximise both the safety and the enjoyment from any high altitude sojourn.

These pages offer advice and guidelines that have been based on previous literature. These pages however should not be taken as the only options and any individual travelling to altitude should seek medical advice from an expert before doing so.

Acute effects of hypoxia; the initial effects of altitude exposure

A number of physiological responses occur when an individual is first exposed to altitude. The awareness of these responses is important for the mountaineer or the recreational climber;

·         An increase in ventilation. i.e. the rate and depth of breathing
·         An increase in both the heart rate (HR) and the cardiac output of an individual
·         Increased diuresis
·         Increased blood lactate
·         Greater red blood cell (RBC) production (Approximately after seven days)
·         Increased perception of effort

Acclimatisation

The acute responses to hypoxia outlined above, indicate the fact that the human body is an adaptive organism that has the ability to adjust to the changing environment around it and that the acclimatisation of the body to altitude, albeit up to a certain point, is possible. Acclimatisation is a term used to describe the slow adaptation of the body to cope with the lower levels of oxygen at altitude and should figure in the planning of all individuals preparing to ascend to high altitude. If adequate time is allowed during a climb to high altitude, the majority of healthy individuals will be able to function unhindered. This, in turn will increase the chances of summiting.

When travelling to high altitude sufficient acclimatisation is also imperative in order to avoid altitude illnesses. The speed of the ascent and the susceptibility of an individual are the two main determining factors culminating in the risk of developing an altitude illness. When going too high too fast, the body is unable to adapt sufficiently and life-threatening illnesses may be the consequence. Susceptibility to such illness differs from person to person, however and an altitude that may evoke symptoms in certain climbers may provoke no such effect in others. Therefore In a group of climbers the acclimatisation process should always be tailored to ensure that the health of the individual who is slowest to acclimatise is maintained.

So what is recommended?

·         Do not rush the acclimatisation phase (It is now possible to start the acclimatisation process prior to departure)

·         Do not sleep at an altitude exceeding 300m higher than the previous night

·         If possible schedule a rest day every 2-3 days

·         Ensure, if climbing in a group, the process is tailored to the individual who is slowest to acclimatise

·         Be aware of the time course of AMS (below)

Acclimatisation to hypoxia is, as already stated, possible up to a certain threshold. It is estimated that the upper limit for the permanent acclimatisation of an individual is approximately 5,000m. Above which the process of permanent acclimatisation becomes impossible as the body starts to deteriorate. Short term acclimatisation, however is possible amongst healthy individuals to an altitude of approximately 6,500m. Above this point (extreme altitude) the body will deteriorate linearly with increasing altitude and supplementary oxygen will usually always have to be administered.

Acute Mountain Sickness (AMS)

The most common illness associated with travel to altitude is termed acute mountain sickness (AMS). AMS develops in mountaineers ascending to high altitudes who are un-acclimatised. The condition usually develops within 6-12 hours of reaching a critical altitude and peaks at approximately 24 hours. Although some incidences of AMS have been reported at as low as 1000m the condition is usually experienced at an altitude of approximately 3,000m and above.

 The incidence of AMS increases with altitude, and hypoxia is the main causative factor for the onset of the illness. When mountaineers ascend rapidly to 2,500 m, about 10% will suffer from AMS, and when ascending to 4,500 m, the AMS incidence will exceed 60%. Therefore an individual climbing Mount Kilimanjaro for example, which stands at a height of 5,985m, should expect to develop at least some of the symptoms associated with AMS and therefore take precautions for both the prevention and treatment of such symptoms.

 AMS is characterised by;

·         Frontal lobe headache

·         Nausea

·         Fatigue

·         Vomiting

·         Tiredness/ difficulty sleeping

·         Lack of appetite

 In more severe cases further symptoms include;

·         Ataxia (decreased co-ordination)

·         Decreased mental status i.e. confusion, aggression

How to treat AMS

During slow ascents with multiple overnight stays at altitude, an individual acclimatizes, and AMS can be avoided, once again highlighting the importance of a well planned acclimatisation schedule and illustrating how prevention is better than treatment. However, often such symptoms, such as a headache, are inevitable at altitude with approximately 96% of all people at high altitude suffering from the symptom. Therefore it is of importance to know what can be done to combat such symptoms at altitude.

It is also of importance to be aware of the time frame of such altitude conditions in order to determine whether an individual has truly passed the vulnerable stage of the illness and can therefore continue with their ascent. This, however in some cases is difficult as the development of symptoms can continue to worsen from anywhere between 12 hours and 3 days.  
  

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 in to a more serious condition. Such measures include;

·         Administration of supplemental oxygen

·         Sufficient fluid replacement

·         The cessation of any further ascent for at least 1 day (or until symptoms are reduced)

·         The use of acetazolamide (Diamox)

·         The use of Paracetamol/Ibuprofen in order to combat headaches

·         If symptoms persist it is imperative individuals descend

General advice whilst at high altitude

 ·         Keep an eye on fellow climbers

·         Be honest regarding how you are feeling, do not lie about,  or undersell any symptoms you may have

·         Be prepared before you leave

·         Make sure you know how to prevent, identify and treat the illnesses that may arise

·         Remember that slow ascent is the most important measure to prevent the onset of altitude illness

·         If you have any existing health conditions prior to departure i.e. diabetes, asthma etc, ensure you see a doctor or specialist to find out the risks your condition may pose to high altitude travel and ensure you  have taken all precautions necessary

The use of the drug acetazolamide has been mentioned a number of times. This drug, with the trade name of Diamox, is used as prevention against the effects of AMS. The drug works by speeding up the acclimatisation process and can also aid the sleep condition of periodic breathing. Although the drug works to reduce the effects of AMS it does not mask the symptoms and mountaineers should be aware that individuals can still suffer from AMS as well as the more serious conditions of HAPE and HACE whilst taking the drug. It is also important to be aware that some people may be allergic to the drug which may cause the tingling of the extremities; however this will cease when the taking of the drug has stopped.

The use of a pressure bag, or a Gamow bag as it is also known, has also been recommended. Although these bags can save lives it is also important to be aware of the accompanying problems that come with such equipment. Such problems include difficulty communicating with an individual inside the bag and the subsequent difficulty in monitoring their situation. Furthermore if dealing with an individual who has lost consciousness a person will need to be inside in order to closely monitor the condition of the ill individual. Moreover such bags can damage the eardrums and in many cases recovery is often short lived. Nevertheless, as already stated such a piece of equipment can save lives at high altitude and it is essential for an individual planning on travelling to such an environment to be aware of such equipment.

Further possible health problems at altitude

·         Blocked nose and sore throat

·         Sun burn

·         Dehydration

·         Heat stroke

·         Hypothermia/hyperthermia

·         Exhaustion

·         Diarrhoea

·         Constipation

 A number of health issues, big and small, are possible to occur when travelling to high altitude and as already stated individuals should be aware of what the risks are. This page has outlined the main and most serious illnesses and provided advice as to how these illnesses can be prevented and treated. Prevention is the best treatment and if properly prepared there is no reason why these conditions should spoil your climbing/ mountaineering experience.  

 Good Luck!

 References;

Burtscher, M. (2007). Arterial oxygen saturation during ascending to altitude under various conditions: Lessons from the field. Journal of Science and Medicine in Sport. 6, 535-537.

Burtscher, M., Brandstatter, E., Gatterer, H. (2007). Preacclimatisation in simulated altitudes. Sleep Breath. 12 (2). 109-114.

Burtscher, M., Szubski, C., Faulhaber, M. (2007). Prediction of the susceptibility to AMS at simulated altitude. Sleep Breath. 12 (2). 103-108.

Maggiorini, M., Melot, C., Pierre, S. Et al. (2001). High altitude pulmonary edema is initially caused by an increase in capillary pressure. Circulation. 103 (16). 2078-83.

Roach, R.C., Hackett, P.H. (2001). Frontiers of hypoxia research: acute mountain sickness.The Journal of Experimental Biology. 18. 3161-70.

Strote, J., Prutkin, J. (2006). High-altitude pulmonary edema presenting 18 hours after descent. Wilderness and Environmental Medicine. 17 (2). 137-9.

Tannheimer, M.A.J., Albertini, A., et al. (2009). Testing individual risk of acute mountain sickness at greater altitudes. Military Medicine. 174 (4). 363-9.