One of my customers called me today to ask why trumpet players sometimes get lighted headed or black out when they are playing high. After we talked for a while he suggested that I should post some of the information on the forum, so here it is.
There are several factors that contribute to blacking out while playing sustained high passages. The physiology involved is quite complex, but here is the condensed version.
Generating the air flow required to play in the upper register generally requires high intrathoracic (inside the chest) pressures. This high pressure has several effects.
1. Return of blood from other parts of the body above and below the chest is slowed down, so less blood enters the large blood vessels leading to the heart, and the heart itself.
2. Pressure is exerted on the chambers of the heart, reducing their filling even more.
3. As a result the heart pumps less blood, resulting in the brain not getting sufficient blood.
4. Too little blood getting to the brain can cause the player to feel light headed, or to nearly or completely black out or faint. The medical term for a loss of consciousness like this is syncope.
Several factors can in turn make this more likely by decreasing the amount of blood available for the heart to pump.
1. Dehydration from heat, lack of oral intake, or other fluid loss. Being dehydrated from being hung over is a prime example of this. Alcohol causes dehydration after it has been consumed because it is actually a diuretic, stimulating the formation of urine. You do not have throw up in order to get dehydrated from alcohol.
2. Alcohol also has the direct effect of opening up blood vessels, causing more pooling of blood in our lower body, and less blood returning to the heart. It is a good thing lead players never drink alcohol.
3. Standing up suddenly causes a brief drop in blood pressure with blood pooling in our lower body until the body is able to compensate by increasing heart rate and constricting the blood vessels in our lower body.
4. Certain drugs (alcohol, some blood pressure and many other medications), medical conditions (diabetes), fatigue, and sleep deprivation, can make it harder for our bodies to adjust to standing up suddenly.
Changes in breathing can also add to the above problems. Hyperventilation (over breathing) decreases the amount of carbon dioxide in our blood. Decreased carbon dioxide causes blood vessels in out brain to clamp down, making it even harder for the heart to get enough blood to the brain.
All of these problems begin to take effect after about 5 to 10 seconds of sustained high playing. In fact, the effect of playing a high note for only a second or two is actually a temporary increase in blood pressure. That is why passing out is usually associated with sustained high passages.
So, want to pass out on stage? Here is the recipe. Arrive in the new city for a gig with jet lag. Go out drinking the night before the gig and get hammered. Wake up hung over in the morning, remembering that you forgot to take your blood pressure meds the night before. Take an extra dose along with the regular one to make up for that. Go to the gig still a little dehydrated, and have a couple of beers to top things up. Get yourself worked into a tizzy worrying about whether you are going to have the chops for that next solo, to the point of hyperventilating just a bit. It does not even have to be enough to notice. Stand up suddenly from your chair and immediately play a long, screaming lick with sustained notes and as few breaths as possible. That should do it. I know, I know, none of us trumpet players would ever do such a thing.
If you do have a tendency to feel light headed in these circumstances here are some suggestions.
1. Take care of yourself. We all know what that means.
2. Keep well hydrated. Beer does not qualify.
3. If you have a solo coming up and you are sitting make sure you stand up 30 seconds or so ahead of when you play so your body can adjust to the new upright position.
4. Play as efficiently as possible, trying to maintain a closed aperture and open throat so that you do not have to generate a hurricane of air and huge intrathoracic pressures to get those notes.
5. Take more breaths during high passages. Every time you take a breath the pressure inside your chest instantly equalizes with the air pressure in the room. More blood gets back to your heart in that time, and it therefore has something to pump. Even the split second it takes for a breath can add up to a better cardiac output, and less chance of getting dizzy or hitting the floor. This does not mean your should hyperventilate or overfill your lungs. That will only make matters worse. The trick is to balance your breathing with fewer, small breaths or pauses, just enough to break the sustained pressure during long high passages. Just get the pressure off for an instant.
I hope some of this will be useful, or at least of interest to people. Falling down is not the worst thing in the world, but it would be a shame to dent up a really good horn that way.