The study, published in the Journal of Thrombosis and Haemostasis, revealed that playing outdoor games regularly reduces the risk of developing blood clots by 39 per cent in women and 22 per cent in men. Thirty-one per cent of the patients and 40 per cent of the control subjects participated in sports on a regular basis.
The study revealed 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 per cent and in a leg vein by 24 per cent. The results were applicable to both men and women.
In fact, the study's co-author F.R. Rosendaal said: "Women were shown to be even more likely to reap the benefits of regular sporting activities than men. 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 per cent."
Although strenuous activity is known to increase the risk of blood clot development in old age, the net effect of participation in sports by old people may be positive. The study also revealed that people who did not participate in sports were more than four-times as likely to develop a blood clot if they were obese than their lean counterparts.
"When we looked at the results, we found that, overall, the mere fact that people took part in a sporting activity at least once a week was enough to lower their risk of blood clots," say the authors.