Blood pressure measures the force that blood places against the blood vessels as it is pumped through the body. It provides an indication of how well the heart muscle is working to circulate blood and oxygen. While most people are worried about it going too high, a sudden drop in blood pressure is not healthy either. Blood pressure that suddenly drops too low can cause its own symptoms and problems. To help manage this condition, it is important to understand what blood pressure is and what danger signs to look for.
Blood Pressure
Every time the heart muscle contracts, it pushes out blood. This blood travels through the blood vessels to be delivered throughout the body. The heart muscle relaxes between contractions. If the heart muscle is strong and the blood vessels are clear, this system can function properly. The heart muscle should also be able to adjust the amount of blood it pumps as the body changes positions or increases or decreases activity levels.
One way to tell how well the heart is working is by taking blood pressure. This is a simple test that involves placing a cuff around the arm that is then inflated to partially close off the blood vessels. The pressure is slowly released, and the sounds of the blood pushing through the blood vessels can be detected. A blood pressure reading is a number listed as a fraction that tells how much force is being placed on the blood vessels walls as the heart pumps and relaxes.
Readings
The top, or systolic, number of a blood pressure reading represents the heart contracting. The bottom, or diastolic, number represents the heart muscle at rest. According to the National Heart, Lung and Blood Institute, a healthy blood pressure reading is 120/80 mmHg. Blood pressure that reaches 140/90 mmHg or higher is considered too high. This means there is too much force against the artery walls and the heart is working too hard.
Blood pressure that drops to 90/60 mmHG or lower is considered hypotension, or low blood pressure. This may signal that the heart is unable to pump hard enough to deliver the blood and oxygen the body needs to function properly. Blood pressure can be chronically low or it can drop suddenly.
Symptoms
The American Heart Association claims that if there are no symptoms present during a sudden drop in blood pressure, then there is no cause for concern. However, if symptoms are present, they may be a sign of an underlying medical condition or emergency. Be on the lookout for dizziness, fainting spells, confusion, changes in vision, nausea, chills, fast breathing and fatigue. Individuals should consult a physician if blood pressure is chronically low, if sudden drops in pressure occur frequently or if symptoms are chronic.
Common Causes
The Mayo Clinic lists various categories of sudden drops in blood pressure. A common cause is postural hypotension or orthostatic hypotension. This is a drop in blood pressure that occurs when changing positions too quickly, such as standing up after lying down. This happens because the signals to increase blood pressure in order to pump the blood back up against gravity fail.
Postprandial hypotension is a sudden drop in blood pressure after a meal. Normally blood pressure increases after eating to supply the digestive system with additional blood and oxygen. However, if this system does not work properly, blood pressure can fall. Neurally mediated orthostatic hypotension occurs in some people after standing for prolonged periods, causing blood to pool in the legs. With these conditions changing positions slowly and/or more frequently or avoiding large meals may help to control blood pressure better.
Serious Causes
A sudden drop in blood pressure can also be caused by a serious illness or injury. It can signal excessive bleeding, dehydration, shock, a serious allergic reaction or a severe infection, or it can be a side effect of a medication or too much alcohol. In these cases, blood pressure that drops too low too fast can be life threatening. If blood pressure tends to drop low constantly, it may also signal a disease of the heart muscle and the inability of the heart to deliver enough blood and oxygen. These causes require medical intervention.
