Neil Johannsen has all kinds of thoughts about exercise — how much, how vigorous, what type. But, for most people, his advice is simpler.

“Do something,” said Johannsen, an LSU associate professor in kinesiology and associate professor in preventive medicine at Pennington Biomedical Research Center.

“If you’re currently sedentary, it’s really bad for you, so get off your behind and do something. Anything is better than nothing.”

Research indicates that Americans are doing plenty of nothing, and all that nothing is causing a lot of health problems, he said.

Since the turn of the century, obesity and diabetes have skyrocketed, Johanssen said.

In 2000, no state had an obesity rate of 26 percent or more of its population, or a diabetes rate of 9 percent or more, according to the Centers for Disease Control and Prevention. That changed in 2001 with obesity in Mississippi and diabetes in Mississippi and Alabama. By 2009, 30 states had those obesity rates, and 15 had that level of diabetes. Louisiana has been in both categories since 2005.

Poor diet is a big part of the problem, but so is inactivity, Johannsen said.

Whereas half of American jobs required moderate intensity physical activity in the 1960s, only about 20 percent do now, according to a study by Timothy Church, who was Johannsen’s post-doctoral adviser at Pennington.

“I think up until the early ’90s, our physical activity levels were still high enough … to offset those additional calories,” Johannsen said. “Now, you have high calorie intake, and now you lose the physical activity that offsets it. I think that’s why you see this explosion in, one, obesity and, two, in diabetes.”

So, get moving.

“A lot of people get really stuck on 'You’ve got to do the guidelines; you’ve got to do 150 minutes a week,' ” he said. “If they don’t do it, they sort of feel like they failed. It’s sort of like a diet. If you don’t make your diet, you feel like you failed, and they just quit.

“I like to start with that message: If you do anything, it’s better than if you do nothing. It gives them this hope that you’re going to get better, and you will.”

While Johannsen starts with that message, he doesn’t end there.

For adults ages 18-64, the target should be two hours and 50 minutes of moderate-intensity cardio exercise per week, or one hour and 15 minutes of vigorous exercise. An example of moderate intensity is a brisk walk, from 2.5 to 3.5 mph.

Finally, add some strength training. This is especially true for older adults to maintain the strength to keep a high quality of life.

“We’re not talking about powerlifting,” he said. “We’re not talking about going into the gym and making yourself so you can’t walk for the next three days with your resistance training. Go in and do some muscle-strengthening, muscle-toning activities, and we’ve seen greater benefits to people’s health.”

Follow George Morris on Twitter, @GWMorris.