Swimming is an ideal form of exercise for older, sedentary people because it puts little weight-bearing stress on the body and is not likely to lead to overheating. However, despite this, we know little about the effect this form of exercise has on the arteries and blood pressure, write the authors, from the University of Texas (UT) at Austin.They found that 12 weeks of swimming significantly lowered blood pressure and improved the function of arteries in a group of sedentary, unmedicated over-50s whose blood pressure was on the verge of "unhealthy" (prehypertension) or in stage 1 of hypertension.