Question
Does blood pressure have a daily pattern? I've noticed that my blood pressure is always lower in the morning than at night.
Answer
Like many body functions, blood pressure has a daily (diurnal) pattern. Blood pressure is normally lower at night while you're sleeping and when you first wake up. As soon as you get out of bed, your blood pressure starts to rise. Your blood pressure continues to rise during the day, usually peaking in the middle of the afternoon. Then in the late afternoon and evening, your blood pressure begins dropping again.
Factors that may cause an abnormal daily pattern, such as high blood pressure in the morning, include:
- Poorly controlled high blood pressure
- Sleep apnea
- Tumors of the adrenal gland
- Kidney disease
- Certain medications, such as corticosteroids
- Night-shift work
- Caffeine use
- Tobacco use
- Too much stress
Blood pressure lowering medications also can alter this pattern because some may not last a full 24 hours. Other medications taken at bedtime are formulated to start working a few hours before you wake up to control the morning surge in blood pressure.
Your doctor can evaluate the significance of an abnormal daily blood pressure pattern. He or she may recommend a 24-hour blood pressure monitoring test. The device used for this test measures your blood pressure at regular intervals over a 24-hour period and provides a more accurate picture of blood pressure changes over a typical day and night.
Last Updated: 04/17/2008
