(Star Global Tribune) —
Study Highlights:
– The human body clock influences blood pressure independent of changes in environment and behavior.
– The internally-driven, daily blood pressure cycle does not appear to be responsible for the known morning increase in cardiac events.
– Volunteers on three different sleep cycles had almost identical internal blood pressure cycles, peaking at about 9 p.m.
– The reason for the peak in heart and stroke in morning hours remains unexplained.
The internally-driven daily cycle of blood pressure changes doesn’t appear to be linked to the known increase in morning heart attacks, according to a study in Circulation Research: Journal of the American Heart Association.
Researchers sought to identify the role of the internal human body clock in the daily rise and fall in blood pressure. In the study, three groups of volunteers showed an internal daily blood pressure variation with a peak at around 9 p.m. — independent of changes in activity and other behavioral influences that can affect blood pressure.
Increased blood pressure is a major risk factor for adverse cardiovascular events. However, the study revealed that the internal blood pressure cycle resulted in the lowest blood pressure occurring in the late morning. This unexpected finding indicates that blood pressure’s internal circadian rhythm — a cycle of about 24 hours that occurs in many biological processes — is unlikely to be linked to the well-documented morning peak in heart events or strokes, said Steven A. Shea, Ph.D., lead author of the study and associate professor of medicine at Harvard Medical School in Boston, Mass.
“We used three complementary experimental protocols and three different groups and found essentially the same results,” Shea said. “That means we’re dealing with something very robust.”
This seems to be written to be confusing. Hoping one of our regular, knowledgeable commenters can help me understand better what they’re saying.
I especially don’t get the BP peaking at 9 p.m. Mine is going down nicely by that time, from the midday peaks when I’m working and dealing with various stressors.
I was on a 24-hour monitor once and my BP increased around 6pm, then went down around 9:30pm (half an hour before retiring, was lowest at 4 am (106/65 with a pulse rate of 42), then rose again to 135/78 pulse rate 53 at 6 am ), half an hour before I got up. Fluctuating during the day depending on activity, with driving around midday in heavy traffic the highest, up to 160/95.
It’s no surprise your Bp rises when under the stress of driving in heavy traffic. Otherwise your numbers are great. Stress will drive it up every time!
Yes, but that was not the doctor’s opinion! He looked at the ‘high BP’ and prescribed ‘Tenormin’. Fortunately, and to my horror, I realized what Betablockers do and stopped the medication after two days. I guess with a pulse rate of 42 during the night I would not be around anymore to tell the tale had I taken the medication for longer. The doctor’s response: “Well, I guess they were a bit too strong for you!” I don’t take any form of medication but being now diagnosed with ‘pre-hypertension’ concerns me a bit. I really appreciate the stories people share on this forum!