WASHINGTON, Nov. 20 (Xinhua) -- Regular participation in sports reduces the risk of developing blood clots by 39 percent in women and 22 percent in men, according to a new study published Tuesday in the Journal of Thrombosis and Haemostasis.

    Researchers from Leiden University Medical Center in the Netherlands evaluated 7,860 people aged 18-70. Patients who had suffered their first blood clot in a leg vein or lung artery were compared with control subjects who had never experienced blood clots. 31 percent of the patients and 40 percent of the control group participated in sports on a regular basis.

    The overall figures for both sexes showed that participating in sports at least once per week, regardless of the type of sport or its intensity, reduced the risk of developing a blood clot in a lung artery by 46 percent and a blood clot in a leg vein by 24 percent.

    Women were shown to be even more likely to reap the benefits of regular sporting activities than men, according to the study. "When we excluded women who were pregnant or receiving oral contraceptive or hormone replacement therapy -- all possible causes of blood clots, the risk for women was reduced by 55 percent," said the researchers.

    They note that, while strenuous activity is known to increase the risk of blood clot development in the elderly, regular exercise is also shown to greatly benefit the heart, and that the net effect of elderly sports participation may be positive.

    The findings also show that people who did not participate in sports were more than four-times as likely to develop a blood clot if they were obese (with a body mass index of 30 or greater) than lean (with a body mass index of less than 25).