Baltimore Longitudinal Study of Aging

Background: \- The Baltimore Longitudinal Study of Aging (BLSA) is a clinical research program on human aging that began in 1958. Volunteers of different ages join the study when they are healthy, and have follow-up visits for life. Visits last for multiple days. Participants are evaluated for many physical elements as well as for brain function. Physical tests are given. Information on mood, personality, and social aspects of life is also collected. This program has contributed more than any other research project to our understanding of aging. Objectives: \- To characterize the many aspects of the aging process and learn how people can successfully adapt to aging. Eligibility: \- Healthy individuals at least 20 years old. Design: * Participants will receive a booklet and video describing the tests they will take. * During a 3-day visit at the study hospital, participants will take the following tests: * Urine will be collected for 24 hours. Blood samples will be taken. A small piece of muscle tissue may be collected by a needle. * A medical questionnaire and a physical exam will be given. * Participants hearts will be tested, including with blood pressure tests and electronic monitors. They will breathe into a tube to test their lungs. * Participants will perform several exercises, including treadmill walking. * Vision, hearing, and taste will be tested. * Bone and joint X-rays may be taken. * Imaging tests will be given, such as an MRI. * Participants will answer questions to test their mental abilities. * Participants will return for follow-up visits every few years for life. The tests listed above will be given at every visit.