More than one out of three American adults are getting less than seven hours of sleep, according to a study released Thursday from the U.S. Centers for Disease Control and Prevention.

The seven-hour mark is the minimum length of time adults should sleep to maintain a healthy lifestyle, and is necessary to reduce risk of obesity, diabetes, high blood pressure, stroke, mental distress, coronary heart disease and early death, the CDC emphasized.

In total, an estimated 83.6 million adults in the U.S. are sleep-deprived, said the CDC, who released their findings based on surveys with 444,306 participants. The report looked at results involving all 50 U.S. states and the District of Columbia, the first time a sleep-related study has canvased all states for its findings.

Some get even less sleep than others—around 11.8% reported a sleep duration of less than 5 hours. The biggest culprits of sleeping less are those between the ages of 35 and 44—around 38% of people in this age group shun more sleep:

A prevalence of a healthy sleep duration was highest among those with a college degree or higher at 71.5%, and around 67% of married respondents get more sleep than either their divorced or single counterparts:

There were also interesting geographical differences in sleep patterns, the study found. Those living in South Dakota are getting more required sleep than those living in Hawaii, where only around 56% of respondents said they were sleeping more than seven hours.

Those looking to improve their sleep duration were advised to make tweaks to their lifestyles. “Lifestyle changes such as going to bed at the same time each night; rising at the same time each morning; and turning off or removing televisions, computers, mobile devices from the bedroom, can help people get the healthy sleep they need,” said Dr. Wayne Giles, director of the CDC’s Division of Population Health, in a statement reported by Reuters.