Bloomberg — Adults who routinely get fewer than seven to eight hours of sleep a night may be at risk for developing high blood pressure, a study found.

For every hour less of sleep, the odds of developing the condition rose an average 37 percent over five years, according to research published in Archives of Internal Medicine. For every two hours less there was an average 86 percent increased risk of developing high blood pressure over five years, lead author Kristen Knutson said.

More than 73 million American adults have high blood pressure, while about 70 million suffer from chronic sleep problems, according to the US Centers for Disease Control and Prevention. People should focus on sleep as part of a healthy lifestyle like they do on diet and exercise, Knutson said.

These results "confirm what we've seen in the lab that there are health consequences to not getting enough sleep or not sleeping well," said Knutson, a research associate and assistant professor at the University of Chicago. "People don't respect sleep relative to diet and exercise as part of a healthy lifestyle."

Researchers in the study followed 578 adults who had their blood pressure and other health signs measured between 2000 and 2001. At the start of the study, the participants were aged 33 to 45 years old. The scientists also measured how long each participant slept using a sensor on the wrist that chronicles rest and activity at two different points in the study.

After five years, each participant's blood pressure was checked again and each was asked about their sleep.

The adults in the study slept an average of six hours each night. Only seven participants averaged eight or more hours of sleep each night, the researchers found.

The less those in the study slept, the more likely they were to see their blood pressure rise, the authors said.

In the study, 14 percent, or 75 people, developed high blood pressure during the trial, the authors said. A U.S. National Health and Nutrition Examination Survey found that the rate of high blood pressure among those aged 25 to 74 years old was 15 percent, she said.

Lack of sleep may affect the body's sympathetic nervous system, which controls how the body responds to stress through the fight or flight response, Knutson said. Chronic lack of sleep or sleep problems may have a long-term effect on the cardiovascular system, increasing high blood pressure, she said. Not getting enough sleep is also related to obesity and diabetes, affecting overall heart health, she said.

Future studies need to examine whether improving sleep reduces a person's risk of developing high blood pressure, Knutson said.

The study, sponsored by the US National Institutes of Health, was part of a larger trial called the Coronary Artery Risk Development in Young Adults, which recruited patients aged 18 to 30 years old in 1985 and 1986 from Chicago, Minneapolis, Oakland, California, and Birmingham, Alabama. Today's results only included participants from Chicago.