Here are four sections on precautions, immunizations, trekking health and altitude acclimatization-AMS.
Here's lots of information, given with care but no responsibility.
DO discuss your trek fitness and suitability with your doctor, especially if you are overweight or over 50!
Anyone with heart, lung and blood pressure abnormalities or a continuing medical condition should have a check-up and get a medical opinion before booking a Himalayan trek. We suggest anyone over 50 years old get a professional checkup that includes a heart stress test. Many recently-retired people have made it to the top of Kala Pattar (5554m/18,222ft) so age need not be a barrier. The older you are, the more important prior fitness preparation is.
This is no reason to avoid trekking. Look after your medication - wear your inhaler on a chain around your neck or keep it in a pocket. There is still the normal risk of a serious attack so brief your companions and trek leader on what to do.
Nepal: Kathmandu is horribly polluted but most asthmatics feel better once trekking.
If it is *well-controlled* diabetes is no reason to avoid normal trekking. You cannot afford to lose the medication so keep it with you at all times and warn you friends on the procedures in case there's an emergency. Your increased energy expenditure will change carbohydrate and insulin levels so it's very important to monitor your glucose levels frequently and carefully and to keep blood sugar levels well controlled.
High blood pressure (hypertension)
Blood pressure will fluctuate more and be higher than usual while on a trek. You should seek the advice of a doctor who is aware of the history of your condition.
Previous heart attacks
Studies have yet to be conducted but it is likely that the level of exertion required on a trek is more significant than the altitude factor. Seek the advice of your doctor.
There is a moderately increased risk of a seizure at altitude, but is not a reason to stop you trekking. You companions must be briefed on all the relevant procedures.
Past history of chest infections
If you are prone to these then bring the medicine you are normally prescribed.
This information is given in good faith but with NO responsibility.
The most accurate immunization advice for visiting Nepal is on CIWEC Clinic's page, Kathmandu's most professional medical clinic. It is worth reading very carefully and printing this advice out, plus what follows, before getting your shots. American doctors (perhaps to avoid getting sued) tend to jab far more needles than is useful. The best people to consult about the vaccinations are clinics specializing in travel medicine.
Malaria in Nepal
Carried only by the lowland Anopheles mosquito, malaria exists in the Tarai
in Nepal (ie below 1000m/3281ft), and across much of the rest of rural Asia.
There's no risk in Kathmandu or while trekking and the risk in Pokhara appears
to be theoretical only. If visiting Chitwan April to October then you can
consider taking tablets to protect against malaria. The actual risk, especially
since you are there for a short time, is minimal, and the side effects of some
drugs less than minimal.
Whether you are or are not taking anti-malarials, the first line of protection, is to avoid being bitten. The Anopheles mosquito is active only between early evening and dawn so you should cover up well between these times and use mosquito repellent on any exposed skin.
Malaria in India
There is NO malaria in the regions we trek in. The risk of picking up malaria in Delhi or en route to/from Manali is extremely small, probably not worth worrying about. You should use mosquito repellent.
Usually passed on in contaminated water; immunization is considered a must by most doctors unless you have had hepatitis A before. The vaccine is Havrix and a full course will give up to ten years protection.
This disease is avoidable since, like AIDS, it's passed by unsafe sex or contaminated blood products. A vaccine is available.
Occasional cases of meningococcal meningitis occur in Nepal. It is an often fatal disease but the vaccine is safe and effective and should be obtained.
The World Health Organization no longer recommend this vaccination.
Prevalent in Nepal and India and if travelling extensively vaccination is recommended. It is less necessary for trekking.
This vaccine is recommended if you have not had a booster in the last 10 years. Many doctors advise a tetanus booster every time you intend to travel for any length of time.
If you escaped immunization as a child a series of vaccinations is recommended. If you have not had a booster as an adult, one may be required. Check with your doctor.
Measles, mumps and rubella
If you did not have these diseases (or the vaccinations) as a child you may need a vaccination.
Japanese Encephalitis B
This disease is transmitted by mosquitoes and there have been sporadic outbreaks in the Tarai (lowland Nepal) and India. Western doctors based in Kathmandu suggest the vaccination only for people working in the Tarai for extended periods. In other words you DON'T need this vaccination.
This deadly virus is transmitted by the bite of an infected animal, usually a monkey or dog. The risk of being bitten is small but it has happened. A vaccination is available but even if you've had it you'll then need a follow-up course of two further injections. If you've not been vaccinated and are unlucky enough to be bitten, a series of six injections should be started within a week or so of being bitten.
Staying healthy while trekking/climbing
Trekking is a wonderful experience but sickness is sometimes a problem. If you do get sick consult with your leader.
Changing time zones knocks people, add the stress of finishing up at work and many people arrive feeling slammed, needing a holiday. This is the time you are most likely to get sick; try to take it easy, and definitely take multi-vitamin tablets. If travelling from America the flights are particularly long and a brutal time change; we recommend arriving a day earlier to recover. We still arrange an included airport transfer and an extra night at the hotel is cheap.
Do NOT drink tap water anywhere except where we specifically discuss. Use bottled or filtered water to brush your teeth even. While trekking we provide filtered and/or boiled water, and our kitchen crews are serious about hygiene.
This is a common problem in developing countries. In normal circumstances when you get diarrhoea you visit a doctor and they conduct some tests and this is the best way to make an accurate diagnosis. However while trekking obviously this is impossible so you may have to be your own doctor if there is no real doctor close by, and consult with your leader.
First, diarrhoea will not normally kill you so urgent treatment is not necessary nor always recommended. Many people over-react and start taking drugs at the first loose stool. Instead wait a few days and see what happens.
Unless it is particularly severe, for example food poisoning, there is no need to stop trekking, just drink lots of water (preferably with some with electrolytes/oral rehydration solution) and listen to your body: if you feel hungry, eat, and if you don't then take lots of soup and light foods. If the diarrhoea is still definitely troublesome after a few days and you are fairly sure of what type it is then you may want to treat it, do consult with your leader.
If you have a pre-existing condition such as stomach ulcers, gall bladder problems, previously perforated intestine etc, be especially careful with self-diagnosis and treatment.
While trekking lower down in the valleys it is hot and you sweat a lot so it is important to replace the fluids you lose. Dehydration make you feel tired and lethargic and can give you a headache. The symptoms are similar to AMS so the easiest way to avoid confusion is to always keep hydrated.
The basic rules are; drink as much and as often as you like, (that does not include alcohol!) even if it seems like a lot. Then drink some more. This can include soups and lots of tea, but even with a lot of liquid food, you should drink a lot of water too. Many people find that with dinner they often drink more than a litre of water, catching up on what they should have drunk during the day. A great guideline is the expression: A happy mountaineer always pees clear!
The "Khumbu Cough"
If trekking for a prolonged period at altitude in colder weatther, this usually strikes. This is a perpetually running nose and an initially mild productive cough. It is caused by breathing excess quantities of dry cold air - so much that you partially injure your bronchi. A cold or infection is the normal cause of this but in this case the irritant is only air however your body reacts almost identically - quantities of clear or white goo. Get rid of it when you can, there is plenty more waiting to well up. Since there is no infection it is pointless taking antibiotics. Throat lozenges help so take plenty.
An inflammation of the bronchi from an infection, ie identical to the Khumbu Cough but instead caused by an infection. Differentiating this from the Khumbu Cough is difficult, but you perhaps experienced a fever and/or some chills. The cough may be more productive. Since it can be a viral or a bacterial infection, taking antibiotics will not always help and is not particularly recommended.
Since you spend most of your time walking, blisters are really worth avoiding. Use boots that have been worn in if possible. Test your boots by carrying a pack up and down hills - along level ground there is far less stress on your feet.
Normally you can feel a blister developing - some rubbing, or a hot spot, or a localised pain. Stop and investigate, even if it occurs during the first 5 minutes, or just in sight of the top of the hill; immediate action is best. The trick is to detect the symptoms before the blister develops. Put tape on or investigate what may causing the problem.
Blister Treatment - If you develop a blister then there are several approaches. If it is not painful then perhaps surround it (not cover it) with some light padding, eg moleskin, and see how it feels. If it is painful and causing problems then pierce it - clean the skin and sterilise the needle; holding the needle slightly above a candle or match flame for a second or two is effective. Do not cut away the dead blister skin until after a few days when it is dried out and no more use for protecting the delicate skin underneath. You can put protective tape over the top with some cotton wool to protect the blister, and some people even put the tape straight over the blister, with no protection.
If you have had a previous history of blisters or think that you are likely to get them take preventative action first. Use moleskin, a strong waterproof zinc-oxide tape or similar, and tape up troublesome areas first. Tape before you take your first step and be religious about checking, and replacing, the tape.
Acclimatization and altitude sickness (AMS)
When trekking or climbing above 3000m/10,000ft it is important to take into account the effect of altitude on your body.
All our trek itineraries are planned with sound acclimatization in mind. We always discuss acclimatization and altitude sickness as part of the trek briefing. Ask for our separate sheet if you want more info than below.
AMS - Acute Mountain Sickness
Commonly called altitude sickness, this has the potential to affect all trekkers from 2500m and higher. Your body needs days to adjust to smaller quantities of oxygen in the air - at 5500m/18,044ft the air pressure is approximately half that of sea level, ie there is half the amount of oxygen (and nitrogen).
For treks below an altitude of about 3000m/10,000ft it is not normally a problem. AMS is caused by going up high too fast and can be fatal if all the warning signals are ignored. Note that it is not the actual altitude, but the speed at which you reach higher altitudes which causes the problems.
Altitude sickness is preventable. Go up slowly, giving your body enough time to adjust. These are the 'safe' rates for the majority of trekkers: spend 2-3 nights between 2000m/6562ft and 3000m/10,000ft before going higher. From 3000m sleep an average of 300m/1000ft higher each night with a rest day every 900-1000m/3000ft.
Starting a trek in Leh or Lhasa breaks these guidelines hence our suggestion of taking Diamox and have some time in the town before heading higher.
Ultimately, it is up to you to recognize the symptoms, and only ascend if you are relatively symptom-free.
Normal symptoms at altitude
Don't expect to feel perfect at altitudes of more than 3000m. These are the normal altitude symptoms that you should expect BUT NOT worry about. Every trekker will experience some or all of these, no matter how slowly they ascend.
Periods of sleeplessness
The need for more sleep than normal, often 10 hours or more
Occasional loss of appetite
Vivid, wild dreams at around 2500-3800m in altitude
Unexpected momentary shortness of breath, day and night
Periodic breathing that wakes you occasionally - consider taking Diamox
The need to rest/catch your breath frequently while trekking, especially above 4000m
Your nose turning into a full-time snot factory
Increased urination - many trekkers have to go once during the night (a good sign that your body is acclimatizing: at Gokyo, Sean from Canada's record, 18 times in one day).
You only need to get one of the symptoms to be getting altitude sickness, not all of them.
Headache - common among trekkers. Often a headache comes on during the evening and nearly always worsens during the night. Raising your head and shoulders while trying to sleep sometimes offers partial relief. If it is bad you may want to try taking a painkiller: paracetamol/acetaminophen (tylenol) or Ibuprofen (Aduil). Never take sleeping tablets. You could also take Diamox: see below. Headaches arise from many causes, for example, dehydration, but if you develop a headache assume it is from the altitude.
Nausea (feeling sick) - can occur without other symptoms, but often nausea will develop with a bad headache. If you feel better in the morning take a rest day, or if you still feel bad descend.
Dizziness (mild) - if this occurs while walking, stop out of the sun and have a rest, snack and drink. Stay at the closest teahouse.
Lack of appetite or generally feeling bad - common at altitude due to too rapid an ascent.
Painful cough or a dry raspy cough.
In other words anything other than diarrhoea or a sore throat could be altitude sickness. Assume it is, because if you have a headache from dehydration, ascending further is not dangerous, but if its due to AMS, the consequences could be very serious. You cannot tell the difference, so caution is the safest course.
Do not try to deceive yourself and accept that you body needs more time to adapt.
Basic rule: NEVER GO HIGHER WITH MILD SYMPTOMS
If you find mild symptoms developing while walking, then stop and relax with your head out of the sun and drink some fluids. If the symptoms do not go away completely then stay at same altitude. Or if symptoms get worse, GO DOWN.
A small loss of elevation (100-300m/328-984ft) can make a big difference to how you feel and how you sleep - descend to the last place where you felt good. If symptoms develop at night then, unless they rapidly get worse, wait them out and see how you feel in the morning. If the symptoms have not gone after breakfast then have a rest day or descend. If they have gone, consider having a rest day or an easy days walking anyway.
Continued ascent is likely to bring back the symptoms. Altitude sickness should be reacted to, when symptoms are mild - going higher will definitely make it worse. You trek to enjoy, not to feel sick.
Note also that there is a time lag between arriving at altitude and the onset of symptoms and in fact it is common to suffer mild symptoms on the second night at a set altitude rather than the first night.
Persistent, severe headache.
Ataxia - loss of co-ordination, cannot walk in a straight line, looks drunk
Losing consciousness - cannot stay awake or understand things very well
Liquid sounds in the lungs
Very persistent cough
Real difficulty breathing
Rapid breathing or feeling breathless at rest
Coughing blood or pink goo or lots of clear fluid
Marked blueness of face and lips
High resting heart beat - over 120 beats per minute
Severe lethargy and drowsiness
Mild symptoms rapidly getting worse
Ataxia is the single most important sign for recognising the progression from mild to severe. This is easily tested by trying to walking a straight line, heel to toe. Compare with somebody who has no symptoms. 24 hours after the onset of ataxia a coma is possible, followed by death, unless you descend.
Basic rule: IMMEDIATE AND FAST DESCENT WITH SEVERE SYMPTOMS
Take as far down as possible, even if it is during the night. (In the Everest region: if you are above Pheriche, go down to the HRA post there. From Thorung Phedi or nearby: take to the Manang HRA post.) The patient must be supported by several people or carried by a porter/horse - his/her condition may get worse before getting better. Later the patient must rest and see a doctor. People with severe symptoms may not be able to think for themselves and may say they feel OK. They are not. They may become combative; ignore.
High Altitude Cerebral Oedema (HACE) - this is a build-up of fluid around the brain. It causes the first 4 symptoms of the mild, and the severe symptom lists.
High Altitude Pulmonary Oedema (HAPE) - this is an accumulation of fluid in the lungs, and since you are not a fish, this is serious. It is responsible for all the other mild and serious symptoms.
Periodic breathing - the altitude affects the body's breathing mechanism. While at rest or sleeping your body feels the need to breathe less and less, to the point where suddenly you require some deep breaths to recover. This cycle can be a few breaths long, where after a couple breaths you miss a breath completely, to being a gradual cycle over a few minutes, appearing as if the breathing rate simply goes up and down regularly. It is experienced by most trekkers at Namche, although many people are unaware of it while sleeping. At 5000m/16,404ft virtually all trekkers experience it although it is troublesome only for a few. Studies have so far found no direct link to AMS.
Swelling of the hands, feet, face and lower abdomen - remove rings. An HRA study showed that about 18% of trekkers have some swelling, usually minor. Females are definitely more susceptible. It is not a cause for concern unless the swelling is severe, so continuing ascent is OK.
Altitude immune suppression - at base camp altitudes cuts and infections heal very slowly so for serious infections descent to Namche level is recommended. The reasons are not well understood.
Drugs you can take - Diamox (Acetazolamide)
This is a mild diuretic (makes you pee a lot) that acidifies the blood which stimulates breathing.
It is suggested that most people trekking above 3500m should take it using the logic that it has the potential to reduce the number of serious cases of AMS: the benefits may outweigh the risks. This topic still requires in depth research. Diamox is a sulfa drug derivative, and people allergic to this class of drugs should not take Diamox. People with renal (kidney) problems should avoid it too. (It also sometimes ruins the taste of beer and soft drinks). The side effects are peeing a lot, tingling lips, fingers or toes but these symptoms are not an indication to stop the drug.
The fully accepted recommendations are to carry it and consider using it if you experience mild but annoying symptoms, especially periodic breathing that continually wakes you up. The dosage is 125 to 250 mg (half to a whole tablet) every 12 hours. Diamox actually helps the root of the problem; so if you feel better, you are better. It does not simply hide the problem. However this does not mean that you can ascend at a faster rate than normal, or ignore altitude sickness symptoms - it is still possible to develop AMS while taking it. Note that it was recommended to start taking the drug before ascending for it to be most effective. For starting a trek in Leh this is not necessary, but it does help. For flying in to Lhasa without prior acclimatization we do recommend starting prior to arrival.
Diamox is not an antibiotic, and so while it works well taken regularly, it doesn't have to be taken regularly.
We have a full altitude acclimatization discussion as part of our trek briefing.