Wash your hands. This advice from your mother was as valuable then as it is now. But how would you feel about receiving this request from a sergeant or lieutenant? According to a study conducted by the Naval Health Research Center, Navy recruits who were ordered to wash their hands five times a day had a 45 percent decrease in respiratory infections, including the common cold, from the previous year. As part of the research published in the American Journal of Preventive Medicine, 40,000 recruits were instructed to use installed soap dispensers throughout the day. Military personnel were chosen for the study because of the tight living conditions, combined with a highly stressful situation — ingredients for sickness.