From the Guidelines
Crossing your legs during a vasovagal syncope episode is a recommended physical counter-pressure maneuver that can help prevent fainting by increasing blood pressure and improving blood return to the heart, as supported by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. When you feel symptoms of an impending faint (lightheadedness, nausea, sweating), immediately sit down and cross your legs while tensing the muscles in your lower body. This physical maneuver works by compressing the veins in your legs, which reduces blood pooling in the lower extremities and increases peripheral vascular resistance. The muscle tension created by crossing and squeezing your legs together forces more blood back to your heart and brain, counteracting the drop in blood pressure that occurs during a vasovagal response. This technique, sometimes called physical counterpressure, is most effective when done at the first sign of symptoms and can be combined with other strategies like tensing your abdominal muscles or squeezing a small ball in your hand. The physiological basis for this intervention is that vasovagal syncope occurs when there's excessive vagal nerve stimulation causing blood vessels to dilate and heart rate to slow, and leg crossing directly combats these effects by mechanically improving venous return. In a randomized, parallel, open-label trial, leg crossing with conventional therapy was superior to conventional therapy in preventing syncope recurrence 1. Additionally, a multicentre prospective trial confirmed the effectiveness of physical counterpressure maneuvers, including leg crossing, in reducing syncope recurrence in patients with reflex syncope 1. Therefore, leg crossing is a simple, non-invasive, and effective technique that can be used to prevent vasovagal syncope, and it should be recommended as part of the management strategy for patients with this condition.
From the Research
Mechanism of Legs Crossing in Vasovagal Syncope
- Legs crossing helps increase venous return, which can abort or prevent vasovagal syncope 2, 3, 4, 5
- The physical maneuver of leg crossing increases cardiac output (CO) and thereby increases blood pressure (BP) 3
- Muscle tensing in addition to leg crossing produces an additional increase in CO and mean arterial pressure 3, 4
- The rise in blood pressure during leg crossing is larger in the elderly 3
Effects of Legs Crossing on Hemodynamics
- Leg crossing significantly increases systolic blood pressure (SBP) but not diastolic blood pressure (DBP) 2
- Squatting and leg crossing can improve hemodynamics in patients with vasovagal syncope and in normal subjects 2
- Leg crossing increases orthostatic tolerance in healthy subjects, with a lower heart rate increase and higher stroke volume 5
Clinical Application of Legs Crossing
- Leg crossing combined with muscle tensing can postpone and in some subjects prevent vasovagal syncope 4
- Patients with recurrent vasovagal syncope can benefit from applying leg crossing and muscle tensing in daily life 4
- Leg crossing is a simple and effective preventive maneuver that can be used in patients with vasovagal syncope 2, 5