veddy interesting. Are you a dipper? Or a non-dipper?

from the link:

5. Be aware of the "Circadian Rhythm" cycle. Your Blood Pressure is highly influenced by the time of day. For normal people, the highest BP occurs about midday, and the lowest at about 3-4 AM in the morning. For some people, described as "non-dippers", this early morning BP dip does not occur. For these people, highest blood pressure usually occurs around 6 AM to 9 AM in the morning. Some doctors are not aware of this, and make erroneous assumptions. A non-dipper may see 150/95 in the morning, and 130/85 in the evening. Non-dipping is usually associated with abnormal sleep conditions, such as sleep apnea, heavy snoring, drug and alcohol abuse, etc.

6. One blood pressure reading means very little. The advice to "Have your blood pressure checked once a year" is useless. What time of day? Had you eaten less salty foods recently? Were you relaxed that day, when you are usually much more stressed? Had you recently exercised vigorously? You must check your BP far more often than once a year, especially if you show "borderline" readings. I can produce a very low, or very high blood pressure AT WILL, based upon what I do during the 24 hours prior to the measurement.

7. Beware of "white coat syndrome", which results in a much higher BP reading than normal, due to the authoritative doctor, the foreboding, sterile exam room, and the smells such as alcohol and disinfectant. All this is not relaxing. Some unaware doctors may prescribe medication, when in fact, you don't need it at all. As soon as you leave the office, your BP returns to normal. This is another great reason to use your own automatic BP wrist monitor, so that you come to know your own body, and the effects of stress, food, mood, sleep, and time of day.