You run 10 miles a day. That's exercise.

How about a brisk two-mile walk? Sure, that's exercise, too.

Let's really dial it back. A 10-minute stroll through the park. Does that qualify as exercise? Or is it simply "being active"?

Some people maintain that you're not exercising unless you're sweating.

"That's not true," said Richard Simmons, a guy who knows something about sweating. (Remember his "Sweatin' to the Oldies" exercise video? It has sold 25 million copies and is still going strong.) "Some people sweat more than others. I'm a sweater."

He detailed his morning workout, which starts at 4:30 a.m.: stretches, 100 pushups, 300 sit-ups, 800 leg lifts, jumping jacks, running in place. It was exhausting just to hear about it.

"Within 30 minutes I am a pool of sweat," he said.

Dr. Ian K. Smith, physician, TV personality and author of "The 4-Day Diet" (St. Martin's Press), is in Simmons' perspiration-soaked corner on this one.

"It's a big misperception that the degree to which you sweat correlates to the degree to which you are exercising or working out. It's just not true," he said. "We all have different sweat thresholds, so that's not a good indication whether we're truly receiving benefits from the exercise."

So working yourself into a sweaty mess may look impressive, but it may not be necessary. A good cardiovascular workout, like that 10-mile run, is great, experts say. But they also say there are other steps people can and should take to improve the state of their health.

The benefits of exercise are determined by many variables: age, level of conditioning, past conditioning. Smith gave the example of an 80-year-old who walks a 15-minute mile. That's much more beneficial than a 15-minute mile turned in by someone who is 40.

Celebrity trainer Jay Cardiello, a certified strength and conditioning coach and certified sports nutritionist, said it is all about improving your health.

"They generally say it takes 20 days before you notice a difference, but automatically your body will start improving internally right away," he said. "You have to take a step back and say, 'What is happening today internally?' Well, you've revved up your heart, your immune system is strengthened. You sweat out some toxins, you're giving (your body) the foundation for increased bone density, you're increasing flexibility, increasing your stamina, you're more alert so you're more prone to eating healthier and you sleep better."

Smith believes that a person should work himself up to a moderate intensity of exercise, as judged by heart rate. The goal is to get the heart rate elevated and keep it elevated to maximize the cardiovascular benefits.

"We like to talk about your max heart rate, which is typically 220 minus your age," Smith said. "That is the maximum your heart can go during a workout, but we like to keep people underneath that. So if you go about 80 percent of your maximum heart rate, that is typically around where you'll be maximizing yourself."

But again, a workout doesn't have to be exhausting. Cardiello offers a simple morning exercise routine that almost anyone can try.

"Stand on your right leg while brushing your teeth, then wash your mouth out, spit, and brush again while you stand on the opposing leg," Cardiello said. "That's exercise. It works your core, stabilizing muscle, and it allows your body to create symmetry or balance for the right and left side."

He also suggests dancing around as you prepare for work.

"You'll burn 50, 60 calories even before you start your day," he said. "You put the music on, it puts you in a good emotional setting. It's a good cardiovascular exercise, you are increasing your bone density because you're stepping down on the ground. So that's exercise."