Swedish researchers have published the results of a prospective cohort study, which indicates that good physical fitness at age 18 years is associated with a reduced risk for serious depression in later life. There was no link with fitness and bipolar disorder.
Investigators reviewed the data collected from over 1 million Swedish men born between 1950 and 1987 who were 18 years old, enlisted for mandatory military service, and with no history of mental illness at the time of enrolment. The subjects were given extensive physical tests which included cardiovascular and muscular fitness, as well as psychological examinations.
Subjects were followed between 1969 and 2008 with data used from the Swedish National Hospital Discharge Register to determine if hospital admission for depression had occurred.
After controlling for a number of factors, investigators found that men who had poor cardiovascular fitness at age 18, showed a greater risk of developing severe depression in adulthood.