Before the headache even starts: The subtle 'micro-signals' your body sends at 3,000m that most completely ignore.

This article is for Independent Trekkers, Climbers and/or for someone who is looking towards their first High Altitude Experience. Please discuss with your Medical practitioner to understand the dosages of Diamox and correct interventions.

Enroute Jannu View Point | Kanchenjunga Circuit Trek | March 2025

I understand as an independent trekker/climber you are down with myriad of choices and decision making when you are traversing the Himalayas. Having to sort through the logistical hurdles, day to day planning and enjoying the journey, sometimes it is easy to be caught off-guard. This article would help to go beyond your average observation and possibly prepare to effectively manage the early onset of Altitude Sickness especially if you are a solo trekker or doing it with your friends unguided. Whether its Kongma La or Tilicho Lake, every season we have had fatalities due to Altitude Sickness and more of them Independent Trekkers.

This article is not to discourage you but to make you aware about the possibilities, prepare you for the symptoms so that you can traverse the high-altitude Himalayan endeavors safely with positive memories. 

The early onset of Altitude Sickness can present itself in various forms; fatigue even in mild-exertion, head ache, loss of appetite, dizziness, etc. One of the most common symptoms and the hall-mark characteristic of Altitude Sickness is ‘Headache’ that usually starts within 6-24 hours of crossing 2500m or above. However before the classic ‘Headache’ and the combination to satisfy the Lake Louise Score, there are symptoms which I am always observant about - 

Fatigue and Weakness – If you are tired or feel exceptionally weak even with mild physical exertion during your hike, it is one of the symptoms you should be more observant about. If you are hiking with a group of friends and suddenly one of your friends start to slow down taking frequent rest and looks visibly weak and tired, it is one of the cautionary signs. 

Loss of Appetite – You are hiking on your usual pace, may be a bit slower than usual pace. You attribute this to the low oxygen environment but you seem to have lost your appetite. This, while seemingly mundane could be one of the symptoms of Altitude Sickness. 

If you observe this pattern when your friend cannot finish a small bowl of Soup or leaves the barely-touched food on the table citing their appetite, this is also one of the instances where you caution yourself. 

Rate of Respiration – When you are hiking and you hike on a slow pace trying to control your breathing, it settles down when you rest but as soon as you hit the trails, your heavy breathing comes back to you. This is also one of the tell-tale signs that your body is overwhelmed with the hypoxic, low-pressure high-altitude environment and moving towards the onset of Altitude Sickness. 

If you observe this with one of your friends, he/she is responding in full consciousness but if they cannot seem to get their breathing under control and exhibits heavy breathing with every step, this should be a caution for you. 

Insomnia or Disturbed Sleep – A seemingly mundane question, ‘How did you sleep last night?’, is also a very good indicator for the slow onset of symptoms. Inability to fall asleep or having a very poor-light sleep that are sometimes accompanied by very vivid dreams is one of the signs that should raise caution. 

Before the onset of Altitude Sickness, these symptoms might appear in mild – moderate form, even without headache. As a Climbing and Trek Guide, I am observing these patterns and possibly trying to identify who is more prone to Altitude Sickness and intervening with the management of it before the symptoms go from Mild to Moderate to Severe which in some cases happens within 24 hours. 

Hence, what do you do when these appear? 

Rule out the causes of Symptoms

If you don’t feel that you can control your breathing or feel extremely fatigued, try some energy bars, take an extended rest break and/or end your day earlier than expected without moving further. This would give your body the time to recover and also, energy bars would give you quick burst of fuel to make it to next teahouse. 

Sometimes fatigue and weakness might be the result of continuous physical exertion. Giving yourself time to rest and recover might be the answer to your perils. 

Lack of Appetite: Trying some sweet and sour candy, Ginger Tea, Salty chips or crackers, etc. instead of the usual foods of the teahouses that might sometime help to recover your appetite. Taking an extended break before and after food in small quantities also provides energy while not overwhelming your body with digestion issues. 

If your lack of appetite is accompanied with other GI issues such as Stomach ache, Diarrhea or Nausea, then it might also be the result of Food-borne or Water-borne illnesses, which makes it a different issue altogether. 

Dehydration also plays a crucial role in your appetite and hence, sipping frequently on water along with electrolytes is a go-to-practice

In case of Headaches, I usually try to rule out other possibly causes before settling as Altitude Sickness. Dehydration, lack of food/energy and cold dry wind buffeting on your head might also be the reason for Headache. 

If you have headache, I suggest you to focus on Hydration, getting some quick easy Carbs, warming up your head with Beanie, possibly Hot Drinks – Lemon, Ginger Tea, etc. to see if the trifecta of aforementioned reasons is not the cause of your headache. If your headache is unbearable, start with a basic dosage of Paracetamol. It works gently to dull your pain without irritating the stomach (unlike Ibuprofen) which might further contribute to your appetite issues.

Your headache usually should mellow down and go away within 2-3 hours given it’s caused by other reasons. However, if the headache comes back as the Paracetamol wears out, you can assume this as an onset of Altitude Sickness. 

Should you treat every Symptoms as concerning?

The short answer is No. However, it should caution you to be vigilant especially if you are hiking by yourself. I like the analogy of Frog inside a Boiling Pot of Water for this one. When you are by yourself, most hikers tend to underplay their symptoms and overestimate their adaptability, until it becomes too late for them to safely descend by themselves. I have heard countless stories from Annapurna Circuit or Khumbu valley when they found hikers lying unconscious on the trail as they were desperately trying to make their way down or for some unlucky hikers never waking up from their solemn sleep or the teahouse owners having to rescue lone hikers, evacuate or call in Heli-evacs. 

This should serve you as reminder that, if you are doing this by yourself, you should be more vigilant and more proactive as you are the sole support mechanism for yourself.  

Now as one of the most easiest Diagnostic tool to understand the onset of Altitude Sickness is called Lake Louise Score (LLS) which I would attempt to explain here in simple terms – 

Symptoms. Mild (1) Moderate(2) Severe (3)

Headache (Mandatory)   

GI Issues - Loss of Appetite/ Nausea /Vomiting    

Dizziness or Light Headedness   

Fatigue/Weakness   

In simpler terms, for Altitude Sickness – Headache is the mandatory symptoms in LLS tool. Give yourself points based on the severity of other symptoms along with Headache and anything more than 3 points means that it is an onset of Altitude Sickness. Usually, the advised waiting period is for at least 6 hours before using LLS to identify AMS. However, if the condition is progressing rapidly from Mild to Moderate to Severe for yourself or your friends, you can safely assume it is Altitude Sickness and intervene accordingly. 

Hence, before we reach the critical threshold of having to rely on LLS, it is imperative to understand the early symptoms that may or may not be paired with Headache and thus, put you in caution which is the reason behind this article. 

What are the interventions?

One of the primary interventions that you can do is to stop your Ascent and spend at least 24 hours on the same elevation. Even if your score is below 3, this is a cautionary sign that your body is sending you that it requires bit more time for acclimatization. 

Now is the correct time to start on the prophylactic dosage of Diamox, not as a Treatment but more as a process of aiding your body to accelerate your acclimatization. I would suggest you to administer the LLS test on yourself and have it at 0 before commencing your ascend. Spending 24 hours on the same elevation with aid from Diamox (if required) should be your priority before ascending further. 

Understanding Mild, Moderate and Severe AMS based on LLS score – 

Usually, the score of 3-5 is considered Mild AMS. Usually accompanied with full dosage of Diamox (250mg) every 12 hours and staying in the same elevation for 24-48 hours is the intervention that is suggested.

The score of 5-9 is moderate AMS. Accompanied with the full dosage of Diamox, you should prioritize descending to lower elevation and rest/recover until your LLS score is 0. You can also use the standard dosage of Paracetamol, active Hydration and ensure you descent to at least 500m lower than your current elevation. 

The score of 9 and above is considered Severe AMS with the high possibility of developing HACE. Usually at this point, you are complete unable for self-descend or physical exertion. It is at this stage when we consider Heli-Evac or being carried down with Mules or Horses. I have had 2 cases when I had to suggest Dexamethasone in this case followed by rapid descent with Mule and in one of the cases, ended the trek. In both cases, we came out unscathed but it is definitely something that you would not want to experience especially when you are in the remote Himalayas by yourself. 

Conclusion

By this time, you must have understood the early symptoms of Altitude Sickness. Most of the times it is the subtle changes in your body which are actively telling you about the oncoming situation. These subtle symptoms even without the immediate concern or variables for LLS scoring system and pro-active management of these symptoms are the key to your successful high-altitude endeavor. Does this mean that you should always hike in paranoia? No, but it certainly helps to understand the subtle signs of your body. You have to be true to yourself and should not mask these symptoms with the time-constraints or personal ego. Adding 1-2 days to your plan would not mean the end of the world but the consequences of ignoring these symptoms are severe and unforgiving.