Residents of Arlington and Fort Worth can put to rest any doubts about how much energy they’ve got.

The American College of Sports Medicine’s 2021 American Fitness Index, released July 13, ranks Arlington fourth and Fort Worth sixth among the big U.S. cities where people get seven or more hours of sleep per day.

The index indicates 72.4 percent of Arlington residents and 70.9 percent of Fort Worth residents snooze at least seven hours daily.

Two other Texas cities appear on the list of the most rested cities: No. 1 Lubbock, with 77.8 percent of residents reporting at least seven hours of sleep per day, and No. 7 Corpus Christi (70.7 percent).

Data from the U.S. Centers for Disease Control and Prevention (CDC) shows 65.5 percent of Texans enjoyed an adequate amount of sleep in 2018.

In 2020, a study by sleep information website Sleepopolis ranked the Houston suburb of West University Place as the country’s 10th best city for sleep in the country and No. 1 in Texas. Other highly ranked Texas cities included Southlake (No. 18), University Park (No. 35), and Highland Park (No. 47). The Sleepopolis study, which examined more cities than the American Fitness Index did, took into account an array of factors, such as obesity, drinking, physical inactivity, smoking, and insufficient sleep.

Here are the cities with the highest shuteye rankings in the American Fitness Index:

1. Lubbock, 77.8 percent
2. Richmond, Virginia, 73.6 percent
3. Minneapolis, 72.8 percent
4. Arlington, 72.4 percent
5. Seattle, 71.2 percent
6. Fort Worth, 70.9 percent
7. Corpus Christi, 70.7 percent
8. Arlington, Virginia, 70.5 percent
9. Aurora, Colorado, 70 percent
10. San Diego and Chula Vista, California, 69.5 percent (tie)

On average, fewer than 65 percent of residents in the 100 largest U.S. cities report getting adequate amounts of sleep, according to the index. The folks behind the index note that inadequate sleep (less than seven hours a day) is a risk factor for diabetes, cardiovascular disease, stroke, obesity, depression, and death. This year, the index included sleep data for the first time.

Lack of sleep also can harm your ability to engage in everyday activities.

“Sleep deprivation’s effect on working memory is staggering,” sleep expert David Earnest, a professor at Texas A&M University’s College of Medicine, said in 2016. “Your brain loses efficiency with each hour of sleep deprivation.”

Unfortunately, napping may not be the cure for sleep deprivation. Sleep expert Michael Scullin, a professor of psychology and neuroscience at Baylor University in Waco, says regular napping disrupts our normal sleep patterns.

Napping is “impeding the quality of your nighttime sleep, it’s making it harder to sleep, and it’s frankly changing your sleep physiology at night so that you’re not getting as good a quality of sleep,” Scullin told the Baylor Lariat newspaper in 2019. “It’s also altering your biological rhythms so that it makes it harder to feel alert when you’re supposed to be feeling alert, and it also makes it harder to feel sleepy when you’re supposed to be feeling sleepy.”