Agree RS. Other tips I was given, is don't cross your legs, either at the knee or ankles and to help avoid deep vein thrombosis, wear elasticated flight socks. Also to combat pressure on your eardrums on take off and landing, suck a boiled scoff. Didn't know until yesterday, that when you fly, apparently your blood thins out. As a precaution therefore, anyone already taking blood thinning medication,should contact their GP for reassuring advice before the flight.