Altitude: How Height Changes Your Body and What to Do About It

Ever wonder why a short hike feels like a marathon once you’re above 8,000 feet? The thin air, lower oxygen, and pressure drop all play tricks on your system. Knowing the basics can keep you from feeling miserable and help you enjoy the view.

What Happens When You Go Higher?

At sea level your blood carries about 20% oxygen. Climb to 3,000 meters and that number falls to roughly 15%. Your heart pumps faster, breathing becomes deeper, and you might notice a headache or a bit of dizziness. Those are early signs that your body is trying to get more oxygen where it’s needed.

Most people start feeling the effects after a few hours of exposure. Common symptoms include:

• Headache
• Shortness of breath with minimal effort
• Nausea or loss of appetite
• Tiredness that doesn’t go away with rest

If you ignore them, the condition can progress to more serious altitude sickness, which can affect the brain (cerebral edema) or lungs (pulmonary edema). That’s why a slow ascent is the best defense.

Practical Tips to Stay Comfortable

1. Climb Gradually. Aim for no more than 1,000 feet gain per day once you’re over 8,000 feet. If you have to go higher quickly, spend an extra night at an intermediate altitude to let your body adjust.

2. Hydrate, but Not Too Much. Dehydration makes symptoms worse, so sip water regularly. Avoid alcohol and caffeine because they can dehydrate you further.

3. Eat Light, Carb‑Rich Meals. Carbs need less oxygen to metabolize, giving you more energy without overworking your lungs.

4. Consider Medication. Over‑the‑counter acetazolamide (Diamox) can speed up acclimatization. Talk to a doctor before you start, especially if you have heart or kidney issues.

5. Know When to Turn Back. If symptoms don’t improve after 24 hours at the same altitude, descend a few hundred meters. It’s a simple rule that saves a lot of trouble.

For athletes, altitude training can boost red‑blood‑cell count, improving endurance when you return to lower elevations. The trick is to spend 2–4 weeks at moderate heights (5,000–7,000 feet) and then either race at sea level or use a “live high, train low” approach—live at altitude, train on the valley floor.

In short, altitude isn’t a mystery. Your body complains because it gets less oxygen, and you can help it by moving slowly, staying hydrated, and listening to warning signs. Follow these basics, and you’ll enjoy the mountain view without the dreaded headache.