Altitude headache explained in plain English
Altitude headache is head pain triggered by rapid ascent, often from low oxygen and pressure changes. Get symptom tips, red flags, and care—no referral.
Altitude headache is a headache that shows up after you go up to a higher elevation faster than your body can adjust. It often feels like a pressure or throbbing pain and can be your first hint that you’re developing mild altitude illness. At higher elevations there is less oxygen in each breath, which pushes your body to change how you breathe and how blood flows in your brain. Those changes can trigger head pain, especially in the first day or two after arrival. In this guide you’ll learn what altitude headache feels like, how to tell when it’s more than “just a headache,” and what actually helps in the moment. If you’re unsure whether your symptoms are still in the “normal adjustment” range, PocketMD can help you think through red flags and next steps, and VitalsVault labs can be useful later if you’re also dealing with frequent headaches at home and want to rule out common contributors.
Symptoms and what it feels like
Throbbing or pressure-like head pain
Altitude headache often feels like a tight pressure or a pulsing ache, and it commonly gets worse when you bend over, cough, or strain. That “worse with effort” feeling happens because pressure and blood flow in your head shift more at altitude. If the pain is mild and improves with rest and fluids, that is reassuring, but it still means your body is asking for a slower pace.
Pain that starts within 6–24 hours
A classic pattern is that you feel okay during travel, and then the headache hits later that day or the next morning after you sleep at altitude. Sleep can unmask the problem because your breathing naturally slows at night, which can drop oxygen levels further. The timing matters because a headache that starts before you even gain altitude points you toward other causes.
Nausea, low appetite, or lightheadedness
When altitude headache is part of mild altitude illness, you may also feel queasy, not hungry, or a little dizzy when you stand up. This combination can make you under-eat and under-drink, which then feeds back into the headache. The practical takeaway is to treat the whole picture, not just the pain—rest, hydrate, and keep meals simple.
Poor sleep and unusual fatigue
At altitude you can feel wired but tired, with frequent waking or shallow sleep. Your body is working harder to get enough oxygen, and that effort can leave you drained the next day. If your fatigue is out of proportion to your activity, it is a sign to pause your ascent and give yourself a full day to acclimatize.
Red flags that need urgent care
Get urgent help if you have trouble walking straight, confusion, fainting, severe shortness of breath at rest, chest tightness, or a cough that becomes wet or frothy. Those symptoms can signal dangerous altitude complications affecting the brain or lungs, and the safest move is usually immediate descent with medical support. A “worst headache of your life,” a stiff neck with fever, or new weakness on one side also deserves emergency evaluation, even if you are at altitude.
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Causes and risk factors
Low oxygen at higher elevation
The main driver is that there is less oxygen available as you go higher, so your brain and blood vessels respond to keep oxygen delivery steady. Those adjustments can increase pressure sensations and trigger pain. The faster you go up, the less time your body has to make those changes smoothly.
Ascending too fast or sleeping too high
You can sometimes tolerate a daytime hike to a higher point, but sleeping at that new height is when symptoms show up. Overnight, your breathing pattern changes and oxygen levels can dip, which makes headaches more likely the next morning. A slower itinerary that builds in “sleep low” nights often prevents the problem entirely.
Dehydration and dry mountain air
High altitude air is often cold and dry, and you lose more water through breathing than you realize. If you are even mildly dehydrated, your headache threshold drops and the pain feels sharper. Hydration is not a magic cure, but it is one of the easiest levers you can pull quickly.
Alcohol, sedatives, and poor sleep
Alcohol and some sleep medications can slow breathing and fragment sleep, which can worsen oxygen dips overnight. The result is that you wake up with a heavier head and less energy to acclimatize. If you want to enjoy a drink, keeping it modest and earlier in the evening is usually kinder to your brain at altitude.
Personal susceptibility and prior history
Some people are simply more prone to altitude illness, and a past episode is a strong clue you might get it again. Migraine history can also make altitude headaches feel more intense, even when the altitude illness is mild. Knowing your pattern lets you plan ahead with a slower ascent and, for some trips, preventive medication discussed with a clinician.
How it’s diagnosed
Your story and the altitude timeline
Diagnosis starts with when the headache began, how quickly you ascended, and what altitude you slept at. A headache that appears after a recent gain in sleeping elevation and improves with rest or descent fits the pattern. Your clinician will also ask about nausea, dizziness, and sleep because those symptoms help separate simple dehydration from altitude illness.
Checking for mild altitude illness
Altitude headache is often part of acute mountain sickness (AMS), which is a cluster of symptoms that can include headache plus nausea, fatigue, dizziness, or poor sleep. The “so what” is that AMS changes your plan: you should stop ascending until you feel better, because pushing higher is when mild symptoms can turn serious. Many clinicians use symptom checklists to grade severity and guide whether you can stay put, need medication, or should descend.
A focused exam and oxygen reading
A basic exam looks at your balance, mental clarity, breathing effort, and lung sounds, because dangerous altitude problems can show up subtly at first. A finger oxygen reading (pulse oximetry) can be helpful, although the number varies by altitude and by person. What matters most is the trend and how you look and feel, not chasing a perfect percentage.
Ruling out other headache causes
Not every headache at altitude is caused by altitude, and it is worth considering migraine, caffeine withdrawal, sinus irritation, or carbon monoxide exposure from heaters or stoves. If you have fever, a stiff neck, a new rash, or neurological symptoms, the evaluation shifts toward infection or bleeding rather than altitude illness. If headaches are frequent even at home, labs can sometimes uncover contributors like anemia or thyroid imbalance, which is where a broad screening panel can be useful.
Treatment options that help
Stop ascending and rest
The most effective first step is to pause your ascent for at least a day, because your body needs time to adjust. Many people improve with rest alone if symptoms are mild. If you keep climbing while you feel worse, you raise the odds that the headache becomes part of a bigger, riskier problem.
Hydration and simple carbs
Drink enough that your urine is pale yellow, and aim for steady sipping rather than chugging. Eating can be hard when you feel nauseated, but small portions of easy carbs can help you keep energy up while you acclimatize. Avoid overdoing plain water without food for long stretches, because that can dilute salts and make you feel weaker.
Pain relief like ibuprofen or acetaminophen
Over-the-counter pain relievers can reduce the headache so you can sleep and function while your body catches up. Ibuprofen is commonly used for altitude headache, and acetaminophen is another option if you cannot take NSAIDs. The key is that pain relief should not be used to “power through” continued ascent when you still feel unwell.
Altitude meds: acetazolamide or dexamethasone
Acetazolamide can speed acclimatization by helping you breathe a bit more and adjust your blood chemistry, which often reduces headache and other AMS symptoms. Dexamethasone is sometimes used for more significant symptoms or specific situations, but it is not a casual travel medication and needs clinician guidance. If you are considering either for a trip, it is best to plan before you travel so you know what to take and when.
Oxygen or descent when symptoms persist
Supplemental oxygen can bring fast relief because it addresses the root issue, which is low oxygen delivery. If you do not improve with rest and basic measures, or if symptoms are moderate to severe, descending is often the safest and most reliable treatment. Even a drop of 1,000–2,000 feet can make a noticeable difference in how your head feels.
Living with it on your trip
Use a “go slow” decision rule
A practical rule is that you should not gain more sleeping elevation until your headache and other symptoms are clearly improving. If you wake up worse, treat that as a stop sign for the day. This keeps you from making a small, manageable problem into a trip-ending one.
Sleep strategies that support breathing
Try to keep your sleep schedule steady, and avoid heavy alcohol at night because it can worsen breathing dips. Some people find that sleeping slightly propped up reduces the “pressure” feeling in the head. If you are using a sleep aid, choose one with a clinician’s guidance because some options can suppress breathing.
Know what to track day to day
Write down your sleeping altitude, your headache severity, and whether you have nausea, dizziness, or unusual shortness of breath. The pattern over 24–48 hours is often more informative than how you feel in one moment. If you need medical help, that simple log makes the conversation faster and more accurate.
Plan for travel and exertion limits
Hard exertion early in a trip can make symptoms feel worse because your oxygen demand spikes. If you must move, keep the pace conversational and take frequent breaks. It is frustrating to slow down, but it is usually the quickest path to feeling normal again.
Prevention for your next ascent
Build in acclimatization days
Prevention is mostly about time. If you can, increase sleeping elevation gradually and schedule rest days after big jumps. Your future self will thank you when you wake up clear-headed instead of foggy and nauseated.
Climb high, sleep lower when possible
Day trips to a higher point can be okay if you return to a lower sleeping altitude afterward. This approach gives your body a training signal without forcing it to cope all night at the higher elevation. It is one of the most effective strategies for trekkers and skiers who have flexible routes.
Limit alcohol and prioritize hydration early
Start hydrating before you feel thirsty, especially during travel days when you may forget to drink. Keep alcohol modest for the first couple of nights, because your body is already working hard to adapt. These small choices often make the difference between a mild headache and a full day lost to symptoms.
Consider preventive medication if high risk
If you have had altitude illness before, or you must ascend rapidly for work or travel, preventive acetazolamide may be worth discussing ahead of time. The goal is not to medicate every trip, but to match the plan to your risk and itinerary. A quick pre-trip conversation can also cover what symptoms mean you should stop ascending or descend.
Frequently Asked Questions
How long does an altitude headache last?
If you stop ascending and rest, many altitude headaches improve within 24 to 48 hours as your body acclimatizes. If you keep gaining sleeping elevation, the headache can persist or worsen. A headache that does not improve after rest and a lower altitude deserves medical attention.
Is altitude headache the same as altitude sickness?
Altitude headache can be a stand-alone symptom, but it is often part of mild altitude illness called acute mountain sickness (AMS). AMS usually means headache plus symptoms like nausea, fatigue, dizziness, or poor sleep. The difference matters because AMS is a clear sign you should not keep going higher until you feel better.
What’s the best medicine for altitude headache?
For pain relief, ibuprofen or acetaminophen often helps, especially when paired with rest and hydration. If the headache is part of AMS, acetazolamide can help your body acclimatize faster, which treats the cause rather than just the pain. Medication choice depends on your health history and trip plan, so it is smart to decide before you travel.
When should you descend for an altitude headache?
You should descend if symptoms are getting worse despite rest, if you cannot keep fluids down, or if you develop red flags like confusion, trouble walking straight, severe shortness of breath at rest, or a wet cough. Descent is the most reliable treatment when symptoms are moderate to severe. Even a modest drop in sleeping altitude can bring meaningful relief.
Can dehydration alone cause a headache at altitude?
Yes, dehydration can cause a headache anywhere, and the dry air at altitude makes dehydration easier to slip into. The tricky part is that dehydration and altitude illness can happen together, so improving hydration does not always fix the problem. If you hydrate and rest but still feel progressively worse, treat it as more than dehydration and stop ascending.