Blood pressure has a daily pattern, and it is normally lower at night while you’re sleeping. Your blood pressure starts to rise a few hours before you wake up. 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.
Having an abnormal blood pressure pattern, such as high blood pressure during the night or early in the morning, can mean that you have a health problem. Associated conditions include:
• Poorly controlled high blood pressure
• Obstructive sleep apnea
• Kidney disease
• Thyroid problems
• Nervous system problems
• Cardiovascular disease
Risk factors for developing an abnormal blood pressure pattern include:
• Night-shift work
• Tobacco use
• Too much stress
• Taking blood pressure medications that don’t last 24 hours
Your doctor can tell you if an abnormal daily blood pressure pattern may need treatment. 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 an average day and night
Blood pressure measurements that are higher at your home than at your doctor’s office could be caused by a decrease in stress at your doctor’s office or an error in measuring your blood pressure at home.
The opposite, higher blood pressure at your doctor’s office than at your home, is often called white-coat hypertension. This means that the stress or anxiety of being in your doctor’s office causes your blood pressure to be higher than it normally is at home, where you feel more at ease.
Having lower blood pressure measurements at the doctor’s office than at home is called masked hypertension. Masked hypertension can occur if a calm, quiet environment at your doctor’s office is less stressful than the environment at home — leading to a lower blood pressure reading at the doctor’s office. Likewise, use of alcohol, caffeine or cigarettes at home can increase blood pressure.
Be sure that your home blood pressure monitor is accurate and that you’re using correct technique. If you’re not sure, ask your doctor. He or she may ask you to bring the home blood pressure monitor to the office. You may measure your blood pressure in one arm with the home monitor while your doctor measures your blood pressure in the other arm with the office equipment.
Still, some people consistently get different blood pressure readings outside the doctor’s office — even when blood pressure is measured correctly and repeatedly. If your home blood pressure readings are accurate and consistently higher than those at your doctor’s office, your doctor will likely manage your blood pressure based on the higher readings.