Did you know that having a window seat during a long plane or bus ride is comparatively risky? No, it's not because you could get sunburn, but because you probably won't stand up and stretch your legs much. "If, on the other hand, you have an aisle seat, you'll likely have to get up fairly often to let out someone sitting next to you. This movement helps prevent a blood clot," says Dr Tomas Jelinek, scientific director of the Düsseldorf-based Centre for Travel Medicine (CRM). A blood clot (thrombus) can form in a blood vessel, for example a deep vein in the legs, when something keeps blood fro...