Hiking at Altitude: High Blood Pressure, Asthma, Migraine

You are planning a walking week or a ski trip, and you have high blood pressure, asthma or migraine. You want to know what the height does to you and what to sort out before you go. You can note symptoms on paper or in the symptom diary in Sam. Sleep and resting heart rate from Apple Health sit in the same app, a few taps from the entry. Your doctor decides what is safe for you.

Whether you can hike at altitude with high blood pressure, asthma or migraine is a question for your doctor before you go. For high blood pressure and asthma, the sources ask for good control first. The CDC advises raising your sleeping altitude by no more than 1,600 feet a day above 9,000 feet.

This text is general information, not altitude advice. No source cited here sets one height limit for all three conditions. Altitude affects everyone, fit or not, and each condition brings its own questions.

At what height does altitude start to matter?

With height, air pressure falls and the air holds less oxygen. The CDC says you may be at risk of altitude illness above about 8,000 feet, about 2,440 metres.

Anyone unadjusted to height, sleeping at about 2,450 metres or more, can be affected. Fitness does not protect you. The usual early signs are a headache, tiredness, poor appetite, nausea and dizziness. The CDC says mild symptoms should settle on their own within a couple of days; if they get worse at rest, go down.

What happens to blood pressure at altitude?

An American Heart Association scientific statement on exercise at altitude says blood pressure can dip briefly when you arrive. It then rises as your body adapts, often ending higher than at sea level for the rest of the trip. The rise shows up more in 24 hour monitoring and at night.

Not everyone responds the same way. Some people's readings stay close to home, some rise and some fall. The same statement says blood pressure should be well controlled at sea level before travel, and that medicines should be reviewed with a clinician.

The American Heart Association news puts it simply. People with high blood pressure, coronary artery disease, heart rhythm problems or heart failure should check with a health care professional before visiting high altitude. Whether your reading is stable enough is for your clinician, not a blog post.

What do the sources say about asthma at altitude?

If your asthma is well controlled, the risk of a flare at altitude is generally low. Cold, dry air and exercise are the usual triggers, and breathing cold air hard can tighten your airways. The CDC Yellow Book lists well-controlled asthma as likely no extra risk, and unstable or poorly controlled asthma as a contraindication for going high. A review of lung disease at altitude describes a personalised pre-travel assessment.

The CDC asks anyone with heart or lung disease to talk with a doctor familiar with high altitude medicine before travelling. A written asthma action plan, your rescue inhaler and a plan for an attack belong in your bag. If you have a cold or chest infection, ask your doctor before you go up.

High altitude headache or a migraine attack?

Many people get a headache at height. The Migraine Trust says about one in four people who climb high get a high altitude headache. It is usually mild and on both sides, starts around 8,500 feet and gets worse when you bend, cough or exert yourself.

High altitude headaches can be intense in people with a history of migraine. Changes in altitude, like flying, high altitudes and weather changes can trigger migraine attacks in some people.

If a headache feels different from your usual migraine, or gets worse, do not push through. The Migraine Trust advises treating the symptoms, resting, and continuing only when you feel fully recovered. Get medical advice if it does not improve.

How quickly should you climb?

Go up slowly. The CDC says once you are above about 9,000 feet, raise your sleeping altitude by no more than 1,600 feet a day. The CDC Yellow Book sets the same idea in metres: above 3,000 metres, do not raise sleeping altitude by more than 500 metres a night, and add an extra acclimatisation night for every 1,000 metres gained. The Migraine Trust suggests not climbing more than 1,600 feet a day above 8,500 feet.

Sleeping altitude matters more than the high point you reach in the day. Drink plenty, eat enough and avoid alcohol. These numbers are upper limits, not a personal clearance. What fits your route is for a guide and your doctor to decide.

Which symptoms in the mountains are an emergency?

Most altitude problems are mild and settle. Two forms can be serious: fluid in the lungs (pulmonary edema) and fluid in the brain (cerebral edema). The CDC says both need a fast move to a lower elevation. Signs include severe shortness of breath even at rest, unusual weakness, clumsiness, confusion, or difficulty thinking clearly.

If your symptoms get worse while you rest, go down. Do not wait it out. In remote areas mobile coverage can drop, so know your route and, if you go alone, tell someone where you are going.

Call your local emergency number (112 in the EU, 999 in the UK, 911 in the US). Neither Sam nor a watch decides whether something is urgent. In doubt, go down and call for help.

What do I ask my doctor before booking?

Take these questions with your route and sleeping heights:

• Is my blood pressure well enough controlled for this height, and how often should I measure on the trip?
• Do I need a check or a written asthma action plan before I go?
• What do I do if a headache feels different from my migraine?
• Do any of my medicines need adjusting, and what should I pack?
• How quickly should I plan to climb, and is there a height limit for me?
• What would count as a reason to turn back or call for help?

Never change or stop a medicine on your own.

What do you record on a trip?

A simple log helps you talk about days instead of a vague feeling. One line per day:

• Date and sleeping altitude, and how it changed from the night before
• The highest point you reached and how long the climb took
• Blood pressure with your own device, as often as you agreed with your doctor
• Resting heart rate in the morning
• How you slept and how often you woke
• Headache yes or no, where, and whether effort made it worse
• Nausea, poor appetite, dizziness, tiredness, sensitivity to light
• Anything that felt like your usual migraine, in your own words
• Shortness of breath only on effort or also at rest, cough, and how often you used your reliever
• Whether you had a cold, and how much you drank

Sleeping altitude and blood pressure you can keep on paper or in a notes app. Symptoms go day by day into the symptom diary in Sam. Sleep and resting heart rate come from Apple Health when data exist. Sam does not read altitude, so the height of your bed stays your own field.

Take your altitude week, with sleep and resting heart rate, into the follow-up

After the trip you have a dated record to bring to the follow-up, instead of a memory.

• Symptoms go day by day into the symptom diary, with a date and how strong they felt, instead of a loose note in your pocket.
• Sleep and resting heart rate from Apple Health sit in the same app, a few taps from the entry, instead of in a screenshot.
• If a doctor has diagnosed you and you switch on Sam's diary for high blood pressure, migraine or asthma (a program with its own doctor report), the doctor report as a PDF covers the period you choose.

Sam does not read altitude and does not measure blood pressure. It never judges whether a height is safe for you.

Try Sam Health

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any condition or health state. Always consult qualified professionals for medical decisions.

Related reading

• Cold exposure and sauna with a chronic illness
• Resting heart rate and high blood pressure: what your wearable shows
• Sleep, resting heart rate and migraine with Apple Health
• Doctor visit checklist for a chronic condition
• Shift Work and Chronic Conditions: What to Record

Sources

Updated: October 2026

• CDC: Travel to High Altitudes
• CDC Yellow Book: High-Altitude Travel and Altitude Illness (2026 edition)
• American Heart Association: Clinical Implications for Exercise at Altitude Among Individuals With Cardiovascular Disease (scientific statement, 2021)
• American Heart Association News: Travel to high altitudes could be dangerous for people with heart conditions
• The Migraine Trust: High altitude headache
• Holthof K et al.: Underlying lung disease and exposure to terrestrial moderate and high altitude (personalised risk assessment, 2022)