Patient description: A 42-year-old healthy woman came to the clinic to have her flu shot in early October. She works in a rehab center and has no underlying disease. It's her first time getting the vaccine this year. She is married for 5 years and uses barrier methods of contraception. Her menstrual cycle is irregular. She does not smoke. She is not on any medications. She exercises regularly for 30 minutes a day at least 5 days a week. She has no history of allergies to any food or drugs. Her past surgical history is significant for tonsillectomy and she is otherwise healthy.

Clinical trial eligibility criteria: eligible ages (years): 50.0-999.0,  Acute Respiratory Infection Aged 50 years or older at study entry. 2) Literacy in English language sufficient for understanding the study protocol and completing questionnaires. 3) Must answer "Yes" to either "Have you had at least 2 colds in the last 12 months?" and/or "On average do you get at least 1 cold per year?" 4) Self-reported ability and willingness to follow through with either exercise or meditation training, or neither, according to randomized allocation. 5) Successful completion of tasks during run-in period, including 2 in-person appointments, 2 phone contacts, and 1 set of homework questionnaires. 6) A score of 14 or lower on the PHQ-9 depression screen, self-reported both at entrance to run-in trial and again just prior to enrollment in the main study. 7) A score of 24 points or higher on the Folstein mini-mental status exam, administered by research personnel at entrance to run-in trial and again just prior to consent and enrollment in the main study. -  Physical or medical condition prohibiting adherence to study protocol. Prospective participants must meet the American Heart Association guidelines225 for suitability for an exercise program. Prospective participants will be advised (but not required) to seek their physicians' advice before enrollment. 2) Current or recent use of meditative practice, or previous meditation training. Assessed by answering "Yes" to any of the following questions: Do you meditate on a regular basis? In the last year, have you meditated at least weekly for 2 or more months in a row? Have you ever been trained in meditation? Have you ever been involved in a mindfulness class or mindfulness practice? 3) Potential participants must not engage in moderate exercise more than twice per week or vigorous exercise more than once per week, as assessed by the following questions adapted from the BRFSS classification226 system: On average, how many times per week do you engage in moderate recreational activities such as walking, tennis doubles, ballroom dancing, weight training, or similar activities that last at least 20 minutes per occasion? A) Less than 1 time per week; B) 1 time per week; C) 2 times per week; D) 3 times per week; E) >4 times per week. How many times per week do you engage in vigorous sport and recreational activities such as jogging, swimming, cycling, singles tennis, aerobic dance or other similar activities lasting at least 20 minutes per occasion? A) Less than 1 time per week; B) 1 time per week; C) 2 times per week; D) 3 or more times per week. 4) Immune deficiency or auto-immune disease (eg. HIV/AIDS, lupus, rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease; Co-Investigator Dr. Muller will advise in questionable cases). 5) Current use or forecasted need for immunoactive drugs (eg. steroids, immunosuppressants, chemotherapy); nonsteroidal antiinflammatories will be allowed. 6) Current use or forecasted need for antibiotic or antiviral medications (eg. prophylactic or suppressive therapy for chronic urinary tract infection, recurrent herpes, or other chronic infections. 7) Malignant disease (prospective participants' physicians to advise. Dr. Barrett to make final decision in questionable cases). 8) Function-impairing psychopathology (prospective participants' psychiatrist or psychologist to advise). 9) Influenza vaccination (flu shots) within 6 months prior to enrollment. 10) True egg allergy or true allergic reaction to prior flu shot, either of which would have to at least one of the following: a) large rash or swelling (more than 12 inches in diameter), b) any swelling in throat, c) any difficulty breathing, d) reaction with hospitalization, or e) anaphylaxis. Reactions that would NOT people: a) local pain or swelling, b) fever, c) malaise, feeling lousy, or d) cold, flu or other infectious illness