Blood pressure has a daily pattern. Normally it’s lower at night while you're sleeping,and it starts to rise a few hours before you wake up, explains Dr. Sheldon Sheps, emeritus professor of medicine and former chair of the Division of Nephrology and Hypertension in the Department of Medicine at Mayo Clinic.
Your blood pressure continues to rise during the day. It peaks in the middle of the afternoon. Then in the late afternoon and evening, your blood pressure begins dropping again.
If you have an abnormal blood pressure pattern - high blood pressure during the night or early in the morning, this may be an indicator that you have a health problem.
These may be:
Among the risk factors for this abnormal pattern are night-shift work, smoking, anxiety, stress and taking blood pressure medications that don't last 24 hours.
Your doctor is the one to decide whether an abnormal daily blood pressure pattern may need treatment. He may also recommend a 24-hour blood pressure monitoring test.