In brief: Everyone, regardless of climate, occasionally feels cold. The hands and feet, with their somewhat remote location from the heart, are particularly prone to cold sensation. But in addition to those who are just cold, there is a group of individuals who have significant problems with peripheral blood flow. These are people who have either primary or secondary Raynaud's disease. The author has developed a simple conditioning treatment that patients can do at home and that can make cold-weather activities possible without pain.