Beginning with the second week, participants in the first and second groups will be asked to complete a brief questionnaire, about the yoga or stretching program, before the first class each week. The questionnaire will take about 1 to 2 minutes to complete. You will also have an ECG and your breathing rate will be measured before and after one of the classes during the third or fourth week and again during the last week. Each stretching and yoga session will be audio and video taped for the purpose of quality control.