Can't Sleep and Can't Relax? The Heart Might Be at Risk

Insomnia with physiological arousal tied to high blood pressure

(RxWiki News) Struggling to fall asleep or relax may do more than cause damage at work or home — it could damage the heart.

A new study found that people with a certain type of chronic insomnia had a greater risk of high blood pressure.

"This is yet another study that demonstrates that insomnia is linked to high blood pressure," said Robert S. Rosenberg, DO, FCCP, author of "Sleep Soundly Every Night; Feel Fantastic Every Day."

"Several studies have shown that insomnia sufferers, especially those who sleep less than six hours a night, are very likely to develop high blood pressure," said Dr. Rosenberg, who is also Medical Director of the Sleep Disorders Center of Prescott Valley, Arizona and sleep medicine consultant for Mountain Heart Health Services in Flagstaff, Arizona. "We believe that there is a physiological as well as psychological component to their insomnia that makes them more vulnerable to cardiovascular disease."

People with insomnia have trouble falling asleep or staying asleep through the night. Many insomnia patients are successfully treated with medications or behavioral therapy.

Some cases of insomnia are marked by physiological hyperarousal — a state where the heart rate is high and the body and mind are active. Like the "fight-or-flight" state, hyperarousal represents a body prepared for action, not relaxation.

The researchers behind this new study, led by Xiangdong Tang, MD, PhD, of West China Hospital at Sichuan University in China, wanted to see whether this state was tied to high blood pressure.

Dr. Tang and team looked at a group of more than 200 patients with chronic insomnia who had been having symptoms for at least six months. This group was compared to a group of people with normal sleep habits.

These researchers gathered blood pressure measurements and diagnoses of high blood pressure. In high blood pressure, or hypertension, the force of blood pumping against the walls of the arteries is high. This condition can lead to heart and kidney problems.

To determine whether the participants with insomnia had hyperarousal, Dr. Tang and colleagues used the the Multiple Sleep Latency Test (MSLT). The MSLT involves four daytime naps during the course of one day.

Dr. Tang and team measured how long it took the patients to fall asleep for up to 20 minutes. It would be expected that insomnia patients — who aren't sleeping at night — would quickly fall asleep in a dark, comfortable room during the day. Those who did not fall asleep quickly were thought to have hyperarousal.

These researchers found that patients with insomnia who took, on average, more than 14 minutes to fall asleep were three times as likely to have high blood pressure than normal sleepers with average MSLT scores of 14 minutes or less.

Patients with insomnia who had an average MSLT score of 17 minutes or more were four times as likely as normal sleepers to have high blood pressure.

Dr. Tang and team noted that hyperarousal — and not only nighttime sleep — should be an aspect of treatment for insomnia.

This study was published Jan. 26 in the journal Hypertension.

A number of groups funded this research, such as the National Natural Science Foundation of China and the Chinese German Joint Center for Sleep Medicine. Dr. Tang and team disclosed no conflicts of interest.

Review Date: 
January 27, 2015