According to a study in the American Journal of Cardiology (Feb 2012), swimming reduces blood pressure and improves artery health.  The study focused on adults ages 50-80, all of whom had pre-hypertension or hypertension but were otherwise healthy but not regular exercisers for the past 2 years.  The swimming group swam 15-45 min/day, 3-4 times/week while the control group spent the time stretching and learning relaxation exercises.  Despite losing no weight or fat, the swimmers’ systolic blood pressure fell 7% in just 12 weeks.  Their arteries also showed signs of becoming more elastic and responsive to changes in blood flow.