There's no better way to get in your exercise than doing it with a bunch of other people. Right? You're all in it together. You stay motivated as you at least try to keep up with the person next to you.

Well, it ain't necessarily so. Especially if you look around and you notice that gravity hasn't done its dirty work on anybody else's body. Or that your head carries the only gray hairs in the room.

You might want to exercise, but you probably won't be back to that class.

A new study backs that up. University of British Columbia researcher Mark Beauchamp has found that the older you get the more likely you are to prefer to exercise alone — with some instruction — than in a room of Spandex-clad twentysomething hard bodies.

Beauchamp's study, which is to be published in the April issue of the Annals of Behavioral Medicine, found that people of all ages generally prefer to exercise with people their own age — or they would rather do it alone.

The study followed 947 people between the ages of 30 and 92. Beauchamp says people in their 30s and 40s didn't mind exercising with people in their 20s. But for people 50 and over, the feelings weren't so positive. People in their 60s and 70s were even less enamored of the idea of exercising with the kids, who weren't too keen on sweating to the oldies.

Beauchamp says the study highlights the need to provide socially supportive environments for older adults to exercise in.

The socially supportive aspect is critical to the success of any exercise program aimed at people who haven't made a habit of regular exercise. That's what makes those marathon training programs at places like The Running Room or groups like JeansMarines so successful. Gather people of similar abilities, let them feed off each other's energy and enthusiasm and they can achieve major goals.

But throw someone into a group of people who are far more talented and — chances are — that person will quickly get discouraged. Maybe they'll exercise on their own, or maybe they'll head back to the couch.