You might want to pack ginkgo biloba and rhodiola along with your ski boots: When you ascend from sea level to a higher elevation, the air is thinner, making it tougher to take in as much oxygen with each breath. The result can be what’s known as altitude sickness—a condition accompanied by headaches, nausea, weakness, and dizziness that could send you straight for the lodge instead of the slopes. Matthew Becker, an herbalist in Boulder, Colorado, recommends taking 120 mg of ginkgo biloba and 200 to 500 mg of rhodiola twice daily for two days before you head for the hills and during your stay. These herbs help the lungs take in more oxygen. If symptoms persist during your stay, up your ginkgo intake to four times a day. If they worsen, however, get medical help; altitude sickness can be dangerous.