Why That First Day Matters So Much
When you travel to destinations above 8,000 feet, the air pressure drops, and there's less oxygen available with every breath. Your body has to work harder to get the oxygen it needs, kicking off a series of physiological changes. Your breathing and heart
rate increase almost immediately. This initial adaptation phase is known as acclimatisation, and the first 12 to 24 hours are the most critical period. Rushing this process can lead to Acute Mountain Sickness (AMS), a condition that feels a lot like a bad hangover and can derail your travel plans.
Know the Symptoms of Altitude Sickness
Acute Mountain Sickness can affect anyone, regardless of age or fitness level. The symptoms typically appear within a few hours of arriving at a high altitude. The most common sign is a headache, often accompanied by one or more other symptoms like dizziness, nausea, fatigue, loss of appetite, and difficulty sleeping. Most cases are mild and resolve on their own if you rest and don't ascend any higher. However, it's crucial to recognise these signs early and not dismiss them as simple travel fatigue.
Your Action Plan for the First 24 Hours
The golden rule for your first day at altitude is to take it easy. Avoid any strenuous exercise for the first 24 to 48 hours. This means postponing that ambitious hike or ski run until your body has had a chance to adjust. Instead, plan for light activity. Gentle walking is better than sleeping during the day because your breathing rate naturally slows during sleep, which can worsen symptoms. If your itinerary allows, try to ascend gradually. For instance, spending a night at an intermediate elevation, like Denver before heading into the higher Rocky Mountains, can significantly reduce your risk of AMS. A key strategy is to "climb high, sleep low," meaning you can explore higher altitudes during the day but should return to a lower elevation to sleep.
Hydrate and Eat Smart
Staying hydrated is one of the most effective things you can do. The air at high altitudes is very dry, and your body loses fluid faster through respiration. Aim to drink significantly more water than you usually would—some experts suggest double the amount. It's also wise to limit alcohol and caffeine, at least for the first 48 hours, as both can contribute to dehydration. When it comes to food, focus on carbohydrates. Your body uses less oxygen to digest carbs compared to fats, making them an efficient fuel source as you acclimatise. Foods like bananas, whole grains, and potatoes are excellent choices.
When to Be Concerned
While mild AMS is common, it's vital to know the signs of more severe and potentially life-threatening conditions. Worsening symptoms despite rest, a severe headache that isn't relieved by medication, increasing shortness of breath even at rest, a persistent cough, or confusion and lack of coordination are all red flags. These could indicate High Altitude Cerebral Edema (HACE), which involves brain swelling, or High Altitude Pulmonary Edema (HAPE), which is fluid in the lungs. If you or someone you're traveling with experiences these severe symptoms, immediate descent to a lower altitude is mandatory, and you should seek medical help right away.
