I joined some friends in a deep-water fitness class a few weeks ago. It was a balmy, 85-degree morning with the usual suffocating Richmond humidity. But when I got in the water, submerged to the neck and afloat only because I wore an Aqua Jogger belt around my waist, it couldn't have been more pleasant.

For 45 minutes, I worked every major muscle group in my body without one drop of sweat trickling down my face. I can't think of another time in the summer that I would describe an outdoor workout as refreshing, but this truly was.

And there were other benefits, too. I didn't feel one pinch of joint pain during the class because there was no pounding.

Plus, there was no need for weights or any other props. The water made the resistance for us.

Instructor Nicole Unice explained that phenomenon as we pushed our arms out to the side, then back in to the front.

"The awesome thing about the water," she said, "is there is four to 20 times more resistance than the air."

Unice taught this particular class at Kanawha Recreation Association in Henrico County. She used to teach water fitness at Southampton Recreation Association in Richmond and also has instructed land and water classes at the YMCA.

But she's quick to remind you that you don't need a class - or an Aqua Jogger, or any other fancy apparatus -to make the most out of the water.

"You can straddle a noodle and do a lot of these same exercises," she said.

Merely walking in the water is good exercise. Running in the water will get your heart rate going even more. And, of course, swimming is excellent cardiovascular work.

So don't just sit there by the pool, lake, river or ocean. Get in the water this summer. Move around, cool off and get a workout at the same time.

If you simply can't motivate yourself to jump in, find a class to join. There are plenty of classes at pools throughout the area.

Woodlake Swim & Racquet Club, for instance, offers about 20 water classes a week. Many of the classes move to the outside pools in the summer, said Sarah L. Hyatt, the club's sales and marketing director.

The water classes at Woodlake have names such as Aqua Stretch & Flex, Yoqua, Cool Run, Wet Intensity, and Sea Strides. There also is a Kids H20 water fitness class.

Traditionally, we think of water aerobics as an exercise format that appeals largely to the retired set. But that's not necessarily so.

At Woodlake, Hyatt said, "These water classes appeal to all age groups, not just the seniors."