BEIJING, China – A new study done in China suggests that trouble sleeping, especially trouble falling asleep, may be related to the body’s high blood pressure.
Dr. Xiangdong Tang of Sichuan University in China and Dr. Alexandros N. Vgontzas of Penn State University College of Medicine, the co-authors of the study, said in a statement that their study is the first to show the possible risk to high blood pressure of people suffering from insomnia, as reported by Reuters.
The study explained that people having insomnia who have increased alertness during the day, or what is medically termed as hyperarousal, triggers a body mechanism wherein there is increased chronic secretion of stress hormones like cortisol, which may then lead to hypertension.
The study includes about 300 adults, 200 of which are chronic insomniacs who had trouble sleeping for at least six months.
All of them spent one night in the Sleep Medicine Center of West China Hospital, where they took a sleepiness and alertness test the following day.
During the night, the participants were allowed to sleep as they normally would, adjusting the sound, light and temperature in controlled rooms. The following day, they were given four 20-minute nap opportunities throughout the day, while the researchers measured their “sleep latency.”
Sleep latency is the amount of time it took for the nappers to actually fall asleep; if they were able to.
Researchers also took records of their blood pressure readings both in the evening and in the morning.
Findings show that normal sleepers were no more likely to have high blood pressure, despite them taking longer time to fall asleep for a nap.
However, for chronic insomniacs, findings show that “the longer it took to fall asleep when they tried to nap during the day, the more likely they were to have high blood pressure, even after accounting for age, gender, weight and height, diabetes, and use of alcohol, tobacco and caffeine.”
The research also found out that people with insomnia, who took more than 14 minutes to fall asleep during the day, were three times as likely to have high blood pressure readings or a doctor’s diagnosis of hypertension.
In general, people who fell asleep in less than 14 minutes, regardless of whether or not they had insomnia, had no increased risk of high blood pressure. Tang and Vgontzas wrote in the statement that in their study, about half of insomniacs and a third of the normal sleepers took more than 14 minutes to fall asleep during the day.
“Insomniacs who have either short sleep at night or show signs of hyperalertness during the day are at risk for hypertension. This is similar to someone who has other risk factors such as obesity, high lipids, smoking, etc,” the authors suggested; adding that people who have trouble sleeping should ask their doctors about their blood pressure readings.