A total of 763 seafarers were selected at random for the examinations. Their number represented 9.82% of the total employed. About 86.63% of them were examined. Another group examined were 202 college undergraduates--all the undergraduates of the second year of studies. The average age of seafarers was 41.14 +/- 8.84 years, and of undergraduates 22.54 +/- 1.29 years. A normal heart first sound was recorded in 95.41% of seafarers, normal second sound in 95.94%, and in 95.05% and 95.05% of the undergraduates, respectively. Normal third and fourth sounds were recorded jointly in 4.45% of seafarers and 0.99% of the undergraduates, whereas abnormal ones in 1.05% of seafarers and 0.99% of the undergraduates. Aortic ejection sound and systolic zone clicks were detected only in seafarers: in 0.79% and 1.31% of the subjects, respectively. Systolic zone murmurs were recorded in 4.19% of the seafarers, including those with heart defects (1.44%), therein mitral valve insufficiency (0.79%), mitral valve prolapse syndrome (0.39%) and aortal valve stenosis (0.26%). In all other cases the recorded heart murmurs in undergraduates and seafarers were considered functional (not pathological).