Graduated compression stockings have been proven to be effective for relieving the heavy, aching, feeling due to varicose veins, and also to help prevent DVT – Deep Vein Thrombosis (Travellers clots) with flying or driving. Over-the-counter stockings that are not graduated compression may in fact increase the risk of DVT. Sequential compression means the stocking or sock is tighter at the ankle, and gradually gets less tight higher up the leg.