No exercise is more popular than walking, and more people walk these days than they did five years ago, according to a new CDC report.

Nonetheless, the majority of adults still need to increase the amount of exercise they get each week in order to meet federal health guidelines. Nearly a third of American adults still get no exercise at all.

"Fifteen million more American adults were walking in 2010, and that's a great first step," CDC director Thomas R. Frieden, MD, MPH, told reporters during a news briefing. "It's a great way to get started meeting the 2 1/2 hours per week of physical activity."

And, Frieden says, people who walk are more likely to meet that goal; 60% of walkers get the recommended amount of exercise each week, about twice as many as those who don't walk.

"That's much higher than those who don't get that 10-minute walk," he says, adding that for people who follow the guidelines, "physical activity really is a wonder drug that makes you healthier and happier... even if you don't lose weight, physical activity decreases your risk of diabetes, cancer, high blood pressure, and other chronic diseases."

The CDC estimates that more than 145 million American adults -- 62% of the population -- took at least one 10-minute or longer walk per week in 2010. That's a 6% increase since 2005. And increases occurred across all populations.

"Because walking or moving with assistance is possible for most persons, does not require special skills or facilities, and can serve multiple purposes, it represents a way many U.S. residents can achieve a more physically active lifestyle, regardless of sex, race/ethnicity, age, or education level," the report's researchers write.

About two-thirds of adults in the West get out and walk, the highest rate in the country. But the South showed the greatest increase of any region, up about 8% in five years. That's good news for a region that, Frieden points out, consistently shows higher rates of diabetes, obesity, high blood pressure, and other chronic health problems.

"This is significant progress we are reporting," he says.

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The ideal walk, says Frieden, is a brisk one. "You should get a little winded," he says.

And the ideal exercise is one that you like doing. "The key concept is to do something you enjoy, to build it into your routine, and to keep doing it throughout your life."

Frieden says there's a need for increased community efforts to promote walking. For example, he says, joint-use agreements between schools and communities have shown success in some regions. These allow people access to tracks for walking after school hours. He would also like to see more communities planned in such a way that shops, schools, and other places are within walking distance of home.

"Many U.S. residents are missing the opportunity to improve their health through regular physical activity," the researchers conclude. "Modifying environments and policies to improve the spaces and increase the number of places for walking might facilitate continued increases in the percentage of U.S. residents who are physically active."

"There is no single drug that can do anything like regular physical activity," Frieden says. "Walking is the easiest, most accessible, and most popular physical activity."