Your blood pressure is the force of your blood against the walls of your arteries as your heart pumps. Every time your heart beats (this is the heart contracting), it pumps blood into the arteries. Your blood pressure is highest when your heart beats and lowest when the heart rests between beats. Blood pressure readings use two numbers, read one over the other. The top number (systolic pressure) measures blood pressure when the heart beats. The bottom number (diastolic pressure) measures blood pressure in between heartbeats. A normal blood pressure reading is 120/80 or slightly lower. If you have a blood pressure reading of 90/60 or lower, you’re usually considered to have low blood pressure (also known as hypotension).
Symptoms of low blood pressure include:
- feeling faint
- heart palpitations (if low blood pressure is caused by a heart problem)
- fever or chills (if low blood pressure is caused by infection)
The following breast cancer treatments can cause low blood pressure:
- Herceptin (chemical name: trastuzumab), a targeted therapy
Other breast cancer treatment side effects also can cause low blood pressure:
- heart problems
- gastrointestinal issues
Managing low blood pressure
- Move slowly. Take a short rest in between lying down, sitting, and standing.
- Stay out of the heat. This includes hot baths or showers — your blood pressure could drop even more.
- Don’t drink alcohol. Alcohol can contribute to low blood pressure.
- Know your medications. Ask your doctor if any of the medications you’re taking can affect your blood pressure.
- Eat a healthy diet full of fruits, vegetables, and whole grains. Your doctor also may suggest adding more salt to your diet to increase blood pressure.
- Drink lots of water to avoid dehydration.
- Talk to your doctor if you have low blood pressure and a history of diabetes, liver, kidney, or heart problems.
Talk to your doctor right away if you experience any of the following conditions that are associated with low blood pressure:
- chest pain or tightness
- shortness of breath
- severe headache
- slurred speech
- weakness on one side of your body
- swelling of your lips or throat
- fever of 100.5 degrees F, chills, or sore throat
- fainting spells
- heart palpitations
- tarry or discolored stools