June 15, 2011 -- A stressful day after a poor night of sleep may be an especially bad combination for blood pressure, a new study shows.
Researchers recruited 20 healthy young adults and measured their blood pressure at rest and then after a stressful task, in this case, giving an impromptu speech where they had to defend themselves for a supposed transgression -- either running a stop sign or taking someone’s wallet.
A week later, after staying up all night, study participants returned to the lab to take the tests again.
Systolic blood pressures, the top number on a blood pressure reading, climbed about 10 points higher when fatigued people were delivering their speeches compared to when they were doing the same task well rested.
“Lack of sleep in combination with stress caused a much higher increase in blood pressure,” says study researcher Peter L. Franzen, PhD, an assistant professor of psychiatry at the University of Pittsburgh’s Sleep Medicine Institute.
It suggests that not getting enough sleep may be involved in the development of cardiovascular disease, he says.
While 10 extra points may not sound like a huge difference, experts who study blood pressure say it’s important.
“That’s clinically relevant,” says David Pollock, PhD, regents professor of medicine at the Georgia Health Sciences University in Augusta.
Previous studies have shown that not getting enough sleep can raise blood pressure, as can stress. But few have looked at what happens when sleepy people are under pressure.
“It’s a fascinating thing because everybody can relate to this,” says Pollock, who says he has borderline hypertension himself. “It’s something that we’ve all experienced this at one time or another. To me, what I’d really like to know is how you can get a good night sleep all the time?”
While the study may be easy to relate to, Pollock says the results need to be replicated by larger studies that look at more diverse populations.
And he says repeating the study will be important because poor sleep and stress seem to go hand in hand.
“Not only is stress common, getting a short amount of sleep is common and one probably leads to the other in a spiral,” Franzen says. “If you’re having a lot of stress, we know that tends to cause insomnia. These things often show up together.”
According to the CDC, one in three Americans has high blood pressure. The condition has few symptoms and is often called the “silent killer” because it can lead to strokes, heart attacks, and heart failure and may damage the kidneys and other organs.
About one in five Americans has hypertension that’s uncontrolled, meaning that it is untreated or that that medications or other treatments have failed to bring it down.
“If someone is having difficulty with blood pressure, maybe having an independent focus on their sleep is important to do,” he says.
This study was presented at a medical conference. The findings should be considered preliminary because they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.