If you live at a low altitude and travel to one that is higher by more than 5,000 feet, you can expect to take 10 to 14 days to adjust to an altitude change. You may tire easily, so reduce physical activity until you become accustomed. Avoid alcohol as it will have more pronounced effects. Altitude sickness symptoms include headache, nausea, fatigue, shortness of breath, and insomnia. Altitude sickness is generally cured by descending to a lower altitude, and if needed, getting oxygen.
Severe cases can become life threatening.
At the first signs of fatigue, take a break. Take an extra set of eyeglasses in case the first is lost or broken. If you cannot afford a second pair take along an older pair. Take along enough cleaning solutions for contact lenses and spare lenses. Even if you wear contacts, it is imperative that you take along a pair of conventional glasses.