Everest Base Camp Trekking: Altitude Sickness and Other Annoyances

EBC Trekking: Altitude Sickness and Other Annoyances


The Everest region is full of dangers. The risks faced by mountaineers during summit attempts are well-known and a huge debate rages over the safety of Everest climbers with so many expedition teams on the mountain.

Trekking carries far less risk, however every year trekkers die and go missing hiking in the Khumbu and Gokyo Valleys. Posters of missing hikers are plastered at trail checkpoints, a stark reminder of just how far out there you really are.   The $20 TIMS card meant to help locate you in the event that you become lost is totally worthless. There is no search and rescue, this is the Himalayas and shit happens all the time.

Planning to trek to Everest Base Camp, Gokyo Lakes, or any of the Three Passes includes becoming informed and aware of the potential hazards.   The popularity of guided treks minimizes risks faced by solo trekkers but that doesn’t mean trekking groups are immune from danger.

Preparing for potential emergencies at high altitude is essential.   Getting informed is the first step. Developing prevention strategies and contingency plans to deal with problems that arise is key.   Foremost is carrying an insurance policy with evacuation coverage that covers trekking activities above 5000 meters.

Knowing how to treat a blister or deal with traveler’s diarrhea is one thing,  more importantly is having a plan to get off the mountain if something more serious should arise. Know what your policy will cover and keep your policy number and contact information on hand should it become necessary.


Descending the icy path from Gokyo Ri must have looked hilarious. We slid, slipped, and fell down the mountain despite each having a set of microspikes inconveniently left in the guesthouse below.


Altitude Sickness

Altitude Sickness is one of the most common and potentially fatal conditions faced by trekkers in the Himalayas. There’s no predicting how the body will adapt to lower oxygen levels on the trek.

Altitude sickness, clinically known as Acute Mountain Sickness (AMS), can become a killer. To avoid a life-threatening situation all trekkers need to acclimate properly. The general rule is to ascend slowly, never sleeping higher than 500 meters from the previous night.

For EBC treks, two nights are recommended at Namche Bazaar (3500 meters) and two nights at Dingboche (4500 meters). After each day of trekking it is important to climb a little higher than your guesthouse and acclimate to the thinner air. Rest days are not just for resting; they are for acclimatizing so climb high and sleep low.


There’s a reason you feel like jumping on acclimatization days, you don’t have to lug your heavy pack with you.


The Center for Disease Control (CDC) recommends taking Diamox (acetazolamide) as a preventative (prophylaxis) medicine for AMS as well as carrying emergency medicines if severe cases develop.

The following article (CDC) outlines the preventative and emergency medicines along with dosage information.

Share this information with your physician in order to have these medicines prescribed (as deemed necessary by your doctor) prior to leaving your home country.

Based on these recommendations, we purchased our medicines in Sri Lanka and India, but also found them available in Nepal. We started taking 125 mg of Diamox twice a day in Namche, and increased the dose to 250 mg twice a day in Dingboche.

Early signs/symptoms of AMS manifest as shortness of breath, breathing faster, and a rapid heart rate. Constant headaches, nausea, loss of appetite, and general malaise are also common. One problem with diagnosing AMS is that many trekkers attribute their symptoms as a normal side effect from the hiking workout and dehydration.

Recognizing the initial phases of AMS is crucial to its treatment. For mild cases, descending to a lower altitude where more oxygen is available is usually sufficient. Severe cases require a rapid descent (usually by helicopter) along with supplemental oxygen and emergency medication.

Helicopters ferry injured trekkers from the Everest region to medical facilities nearly every day in peak season, in fact it’s a big business. At night, there are no rescue helicopters, and finding an oxygen bottle at your guesthouse might just be a far stretch. This is when AMS becomes deadly. If AMS progresses to a severe form, having emergency medicine on hand could be a lifesaver (see link to CDC.)


The necessary evil. Helicopters provide a safety net for trekkers and mountaineers. These noisemakers also disrupt the tranquility of the trek


Experiencing Altitude Sickness On The EBC

Day 8, Lobuche, 2am.  When Teo woke in the middle of the night gasping for air feeling on the verge of panic, there was no chance we’d be climbing any higher that day.  We’ve dealt with altitude sickness during past treks in the Peruvian Andes and it was something we never wanted to experience again.  When symptoms of AMS are present do not ascend to a higher altitude to sleep.

We didn’t make it to Everest Base Camp.  As disheartening as it was to turn around after hiking to within hours of our goal, Lobuche is not the place to test your limits.  Learning to recognize AMS symptoms and obeying the guidelines could save you a lot of grief and maybe even your life.

We came to Nepal better informed and prepared to deal with AMS should it occur. We followed the ascending guidelines and took the recommended prophylaxis medication, but what made the difference was recognizing the symptoms and not ignoring them.

Failure to recognize the early symptoms of AMS  is what gets trekkers into trouble. The EBC trek is not cheap and many people want to push the limits to scratch the trek off their bucket list.   Some trekkers choose to ignore symptoms disregarding the fact that altitude sickness won’t get better with continued ascent.

Often times descending to a lower elevation for an extra night is all that is needed. In fact, that’s exactly what we experienced. After dropping down to 4600 meters for the night, Teo’s breathing issues disappeared and two days later we crossed Cho La Pass at 5420 meters, our highest elevation ever. Two days after that, we ascended Gokyo Ri at 5380 meters.

Even though we missed Everest Base Camp and the Kala Patthar hike, having one more day to acclimate was all that was needed for Teo to be comfortable at similar elevations.


Preventing Altitude Sickness

Altitude affects everyone differently and the acclimatization guidelines are merely suggestions. Diamox has a place but is certainly not one hundred percent effective in preventing altitude sickness.


Standing above the Ngozumba Glacier in Gokyo Valley staring into the high peaks separating Nepal and Tibet.


Pre-trek conditioning is essential. Engaging in exercises that require being on your feet hours on end is beneficial (hiking, running, walking). Even better would be training at high altitudes (greater than 8000 feet).

Staying hydrated on the trek is key and drinking 4-5 liters of water a day per person is recommended. Eating enough calories on the trek is another important consideration.  Without sufficient energy the body will deteriorate.  The tea house menus do get boring so pack along your favorite snacks. Avoid, alcohol, illicit drugs, opiates, and benzodiazapines (some anti-anxiety meds and sleeping pills as they suppress your breathing).

We met a physician in Dingboche who had performed a trial study on altitude sickness in Everest Base Camp trekkers in 2016.  Her published results indicate that acetazolamide 250 mg twice a day and ibuprofen 400 mg three times a day had the best effect for reducing altitude sickness.  The study was performed on trekkers hiking above Dingboche in 2016 and published in a wilderness medicine journal (sorry, we don’t have the link).

Himalayan Weather and Other Annoyances

The Himalayan weather can be unpredictable. The best time for trekking is September-November and March-May. Regardless of when you start, be prepared for four seasons in one day. We hiked in April and by the fifth day we were wearing our thermal layers day and night.   It snowed on the tenth and eleventh days, and the trail conditions ranged from fresh powder, to ice, to slush and mud.



Gokyo Ri summit morning, wearing just about every article of clothing we’ve got.

Our waterproof pants and jackets and Gortex hiking shoes (not boots), kept us relatively dry and we had multiple layers of lightweight technical clothing for warmth. Know the limitations of your equipment. We packed a minimalist wardrobe but it proved sufficient.

Frostbite is a real issue and having proper footwear is essential.  (Click  here to read about our EBC Minimalist Packing Guide).

We experienced only one dangerous animal on the entire trek.  Yaks have been known to knock trekkers off the trail (sometimes to their death).  The yaks ferrying gear up to the higher altitudes are mostly docile creatures and yak attacks on humans are fairly rare occurrences. Don’t let your guard down when yaks are present.

On Day 12, we were passed by a herd of yaks that included one small baby (calf). We were both hugging the uphill side of the trail (as you are supposed to) but we were separated by a bend and couldn’t see each other. The momma yak got really angry for some reason, gave a snort and charged at Teo who received a head-butt on her thigh before she could get out of the way.

The women shepherding the animals were trying to scare the angry yak by yelling and throwing small stones. Johnny joined them only to have the same yak charge us all. After much yelling, stone throwing and tree climbing, the ordeal was over.   It could have been much worse than a big bruise.

Rockfalls are another nuisance to be aware of.  We scrambled quickly to avoid falling rocks just as we were climbing out of the Ngozumba Glacier between Thagnak and Gokyo.  Anytime you hike on steep terrain there is a chance of falling rocks.


***The purpose of this article is to provide prospective trekkers to Everest Base Camp information on the potential dangers of high altitude treks. This information does not replace a consultation with a medical professional. Please consult your personal physician to discuss recommended medications and dosages for your trek.


Nepal Trekking Tips Part 3: Altitude Sickness and Other Annoyances on the EBC is part 3 of a 4 part series about our experience trekking in Nepal’s Himalayas.

Click here to read part 1: How Much It Costs To Trek EBC Independently

Click here to read part 2:  Everest Base Camp Trek: Guided or Unguided

Click here to read part 4: EBC Minimalist Packing Guide

Click here to read about our Everest Base Camp and Gokyo Lakes Itinerary…Unguided

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