If you are the type to faint when you have a flu shot or when blood is taken, I thought the following study was important enough to reprint. It might help you the next time around.
It turns out that there is some selective advantage to fainting. Some of our ancestors who fainted at the sight of blood or upon feeling pain on the battlefield thereby survived and went on to have children, thereby also passing on this genetic trait. For example, I fare quite well, looking at the blood of others, but must recline when I cut myself or else fall down helplessly. Here's the article:
Simple maneuvers can decrease vasovagal syncope episodes
Clinical question
Can a simple counterpressure maneuver prevent vasovagal syncope in susceptible patients?
Bottom line
A simple set of maneuvers (crossing and squeezing legs, grasping a ball tightly, and arm tensing) was effective in decreasing the number of patients with presyncope who experienced a syncopal episode. The maneuvers are simple to perform and can provide an effective way for patients to decrease their number of syncopal episodes if they have prodromal symptoms or can identify triggers that might cause syncope. (LOE = 1b)
Reference
van Dijk N, Quartieri F, Blanc JJ, et al, for the PC-Trial Investigators. Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope. J Am Coll Cardiol 2006;48:1652-1657.
Study design: Randomized controlled trial (nonblinded)
Funding: Government
Allocation: Concealed
Setting: Outpatient (specialty)
Synopsis
The authors recruited 223 patients with recurrent vasovagal syncope and recognizable prodromal symptoms. The patients, with an average age of 38 years, had at least 3 syncope episodes in the previous 2 years or at least 1 syncopal episode and 3 presyncopal episodes in the previous year. Vasovagal syncope was diagnosed using the European Society of Cardiology guidelines and included tilt-table testing. Patients all had a normal electrocardiogram result. Using concealed allocation, patients were r andomized to receive either conventional therapy or training in physical counterpressure (PC). Conventional therapy consisted of an explanation of the mechanism of syncope and advice regarding lifestyle modification. PC training consisted of teaching the patients a set of maneuvers -- leg crossing, handgrip, or arm tensing -- to be performed in situations known to provoke syncope or when prodromal symptoms occur. Leg crossing included tensing of the leg, abdominal, and buttock muscles. Handgrip consisted of squeezing a ball or any available object using the dominant hand. Arm tensing occurred by gri pping 1 hand with the other while abducting both arms. Patients were instructed to breathe normally and choose one maneuver and hold it until the symptoms disappeared or to move on to another maneuver, if necessary. Over 14 months, the number of patients reporting at least 1 presyncopal episode was similar in both groups: approximately 75%. However, patients in the PC group had fewer episodes of syncope (32% vs 51%; number needed to treat = 5; 95% CI, 3 - 17). Patients were instructed in the methods and then given biofeedback to gauge their blood pressure response to the maneuvers. Simply teaching the methods in the office, without this feedback, might not be as effective.