Recently, a reader wrote to say, “I’ve had high blood pressure for two years, but mostly in the morning when it is around 160/80, while at night it goes down to 100/50 sometimes. I am not taking any conventional medicine. My question is what is the reason for such high blood pressure in the morning—and why would it fluctuate so much within 7 to 8 hours from night to morning?”
I know many of you experience the same thing, and here’s why it happens. Serum cortisol, which activates the autonomic nervous system and can drive up blood pressure, peaks in the early morning hours. Ask your doctor to check your levels with a 24-hour salivary cortisol test (samples are saved every four hours for 24 hours).
Researchers speculate that the higher incidence of sudden cardiac death in the early morning hours on Saturday and Monday may be due to excessive cortisol levels. I agree with my colleague, the late Dr. Robert Elliot, who theorized if your home or work is an emotional combat zone, then “gearing up” to face the weekend or work week can trigger lethal conversations between the mind and the body.
I share this because your blood pressure is high upon awakening, and settles down nicely as the day progresses. Usually blood pressure levels come down during the night, with the rest and recovery of sleep, and elevate over the course of the day with activity and stress. So, I’d ask: Do you have any psychological stress as you face your day that is somehow relived once you get rolling throughout your day?
It never hurts, as well, to have a treadmill exercise stress test to see how your blood pressure responds to light activity and more intense exercise. In fact, everyone should get a baseline stress test by the time they are age 50, just to check and have something to compare to in the future.
For healthy, non-hypertensive people, walking around can lower the diastolic blood pressure. For those with psychological stress, walking can also lower systolic blood pressure. In that latter group of people, we often see a higher baseline pre-exercise blood pressure and a nice normalization once they are “in motion.” Walking may be just the thing you need, so consider joining the walking club on my blog.
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