The Schilthorn is 2970 m high. Anyone can suffer from (light) altitude sickness from about 2000 m. It often helps to take things slow and sit down for a while. Special precautions apply to children under 2 years old, as well as people who are pregnant or in poor health: before visiting areas over 2500 m, you'd better consult your doctor. In most cases, staying at such altitudes for just a few hours is no problem.