New Health Guide

Causes of Low Blood Pressure

May 13, 2015

With each beat of your heart, blood is being pushed against your arteries. The amount of pressure created by this process is known as your blood pressure. Hypotension, or low blood pressure, is often regarded as a healthy outcome. However, hypotension can also indicate underlying conditions that need treatment. If your low blood pressure is causing you to feel dizzy or tired, it is time to speak with your doctor.

What Is a Low Blood Pressure Reading?

There are two phases of blood pumping against your arteries that are measured when checking your blood pressure. They are the systolic pressure and the diastolic pressure. When you see them written out, you will see a two numbers written like a fraction. The number on top is the systolic pressure, and the number on the bottom is the diastolic pressure.

  • Systolic pressure is the measurement of the pressure on your arteries when your heart is actively pumping blood, and happens during a heartbeat.
  • Diastolic pressure is the measurement of the pressure on your arteries when your heart is between beats, and is not actively pumping blood.

A healthy blood pressure reading will have a systolic pressure between 110 and 140, although this pressure is not considered low until it drops below 90. The healthy range for diastolic pressure is between 60 and 90.

When determining if your blood pressure is low, both the systolic and diastolic pressures do not need to be below the normal threshold. Only one of these pressures falling below normal qualifies as hypotension.

  • Low systolic pressure is when your systolic reading falls below 90.
  • Low diastolic pressure is when your diastolic reading falls below 60.

What Are the Causes of Low Blood Pressure?

Your blood pressure will naturally vary, and variances in the measurements don’t necessarily indicate a problem. Depending on things like the position of your body, the rhythm of your breathing, you level of stress, the physical condition you are in, any medications you might be taking and the food and beverages you are consuming all influence the pressure placed on your arteries. Your blood pressure is naturally lowest at night when your body is at rest, and will rise substantially when you wake. With this in mind, even the time of day can have an effect on the outcome of your blood pressure measurements.

Several conditions can cause low blood pressure, like:

1. Pregnancy

Due to the rapid expansion of the circulatory system during pregnancy, a woman’s blood pressure typically drops during this time. This is a normal response to pregnancy, and will likely return to normal after giving birth.

2. Heart Problems

Since blood pressure is directly related to the pumping of the heart, conditions like a very low heart rate, problems with the heart valves, heart attack and heart failure can all cause the blood pressure to be lowered.

3. Severe Allergic Reaction

Certain reactions can cause a dangerous reaction known as anaphylaxis. Food, some medications, venom from insects and latex can all trigger anaphylaxis. Common symptoms include problems breathing, swollen throat, itching and hives.

4. Medications

  • Diuretics like furosemides and hydrochlorothiazide cause lower water levels in your body, which can lower your blood pressure.
  • Alpha blockers like prazosin and labetalol, as well as beta blockers like atenolol, propranolol and timolol can have an effect on your blood pressure.
  • Drugs for Parkinson’s disease like pramipexole or medications that contain levodopa, and antidepressants like doxepin, imipramine, protriptyline and trimipramine are famous for lowering blood pressures.
  • Erectile dysfunction medications like sildenafil or tadalafil can also lower your blood pressure.

5. DailyLife Causes

Many every day influences can cause a drop in your blood pressure.Your blood pressure will naturally increase with age, but movement and eating will have a more substantial effect and cause it to drop.

  • Poor diet that is lacking in certain nutrients like B-12 and folate can cause anemia, a condition that causes an insufficient amount of red blood cells to be produced, causing low blood pressure.
  • Even mild dehydration can cause a change in your blood pressure.
  • Stress causes your heart to beat faster, raising your blood pressure. If you are more relaxed, your heart slows and your blood pressure will drop.
  • Exercise might raise your blood pressure for a while, but a healthy body that is in shape will have a lower resting heart rate, and lower blood pressure.
  • Warm temperatures might cause your blood pressure to fall a bit, and your blood pressure will be lower after you have eaten because digestion is a lot of work that requires the use of a lot of blood.

6. Other Causes

  • Endocrine problems: Thyroid disease or adrenal deficiency can both cause the blood pressure to be low. Low blood sugar and in some cases diabetes can also affect your blood pressure.
  • Severe infection: Infections that enter the bloodstream like septicemia cause a dangerous drop in your blood pressure leading to septic shock, which can be fatal.
  • A dramatic loss of blood can cause a dramatic lowering of you blood pressure, as there is less blood pumping through the arteries.

What Are the Possible Symptoms of Low Blood Pressure?

Symptoms of low blood pressure include:

  • Dizziness or feeling lightheaded
  • Fainting
  • Trouble concentrating
  • Blurry vision
  • Nausea
  • Cold and clammy skin that is pale
  • Breathing that is rapid and shallow
  • Fatigue
  • Depression
  • Unquenchable thirst

Note: Most of the time, low blood pressure isn’t serious. However, if you notice any of the symptoms above you should consult your doctor, because constant low readings could imply some more serious problems. And when symptoms occur, keep a record of them and the time they appeared as well as the things you were doing.

How Is Low Blood Pressure Treated?

Most of the time, low blood pressure requires no treatment. If the condition is severe, you may need to receive blood delivered through an IV, medication to improve the heart and the pressure or antibiotics if there is an infection. If you experience a drop in blood pressure caused by standing too quickly, your doctor will likely look at causes like medications you are taking or not drinking enough fluids. Your doctor might also suggest wearing compression stockings to prevent blood from collecting in your lower body.