The participants were recruited in Spring 2009, 2010, and 2011 through regional newspaper advertisements and solicitations in the Movement Disorders Clinic at the University of Iowa and the Veterans Affairs Medical Center of Iowa City. We phone screened respondents and evaluated eligible candidates in-person using clinical examination, MMSE, 12-lead ECG, blood count and biochemistry, followed by graded exercise test using cycle ergometry within one week of starting the intervention. At each visit, we obtained body weight and height, heart rate and blood pressure after 5 minutes of supine rest [Goldberg et al. 1988] and after 3 minutes of standing. Throughout the study, the medications of participants continued to be managed by their treating neurologists.