Editor's note: To hear more of Dr. Matthew Sleeth's advice, tune into "Sanjay Gupta M.D." this Saturday at 4:30 p.m. ET & Sunday at 7:30 a.m. ET.
(CNN) -- Dr. Matthew Sleeth is a former emergency room physician. He's also the author of "24/6: A Prescription for a Healthier, Happier Life."
CNN: You begin your book by writing about a store owner who vowed to close his store on Sundays, so his employees and their families, as well as his customers, could take the day off. But it didn't stay that way for long. What happened?
Sleeth: For almost 2,000 years, Western culture stopped -- primarily on Sunday -- for about 24 hours. Even when I was a child, you couldn't buy gasoline, you couldn't buy milk. The drugstores weren't open. The only thing that was open was a hospital. Even in dairy farming country, we would milk cows, but we wouldn't bring in hay.
And so society just had a day where they put it in park. (That) was Sunday... until the last 30 years or so.
CNN: Why do you think taking one day off a week is so important?
Sleeth: We go 24/7 now, and I think it's having health consequences. I think more and more, there's a consensus that it leads to depression and anxiety.
It's interesting, when a doctor sits down and does a primary intake with a new patient, they ask about smoking, exercise and diet, but they don't ask how much you're working. They don't get any sense of if you're working seven days a week, or if you have time set aside -- like people have always had -- for rest.
I think the lack of rest is reflected in our saying, "We don't have enough time." I think it's pretty much generally felt that we don't have enough time to really get to the things we want to do in life.
CNN: You write about incorporating a "stop day" into your weekly schedule. How do you think that can extend and enrich your life?
Sleeth: A "stop day" is a day you really cease from your labors. This really comes in Western cultures from the Ten Commandments. The fourth commandment tells us to remember the Sabbath. The word "Sabbath" simply means "to cease" -- to cease from your labors.
Now, the definition of labor has changed over the centuries and the millennia. For some people, resting from their labors might mean resting from their sedentary job that they have, putting on tennis shoes and going for a run. For those who work physically, that would mean coming to rest.
In the book "24/6," I don't try to define what rest is for a person, but I ask you to figure out what work is for you, and don't do it one day out of the week.
CNN: You go as far as to say that going full-throttle 24/7 is an illness. How do you recognize the signs?
Sleeth: I find that there's a growing epidemic, really, of depression. We're the most depressed country in the world.
The World Health Organization says somewhere between one in nine and one in 10 Americans are being treated for depression. We tend to work more hours than any other country in the world; Japan is second closest.
When we're constantly going, we pour out chemicals to try to meet those stresses. We have short-term stress hormones like adrenaline, and longer-term hormones like the steroids that we pour out. Those chemicals constantly being "on" are bad for us, and they lead to anxiety and depression and to, I think, diabetes and being obese.
It's interesting that if I took somebody in the emergency department and gave them a big slug of adrenaline, you'll find that an hour later they're just wiped out, and that'll really persist throughout the day. I think that's what we're doing to ourselves. We're constantly bringing stress into our life, and the idea of having one day a week that I can count on to stop is very reassuring.
Even if on Monday I'm very, very busy -- and that proceeds throughout the week -- if you know you have a habit of a weekly day of rest, of stopping, then you always know that's out in front of you. A lot of people "go" and never know when it is that they're going to come to rest.
CNN: You also say this mantra has made a big difference in your own life -- for you as well as your family. How so?
Sleeth: My family and I adopted this about a decade ago. My children were in high school, and they went through high school, college -- and my son even through medical school -- keeping one day of rest, where they didn't study.
They got their work done in advance. I think it actually helps you to order your life, because in preparing for that day of rest, you... actually get more things done on the six days that you are working.
So for our family, we took it very seriously. My kids really became the guardians of it when they lived at home, and they really wanted to see it happen. I think it actually helped us as a family.
I have many people that I've talked to now that have said that keeping one day of rest a week has been the single best thing they've done for their marriage, their family and their spiritual relationship.