Until recently, my favorite workout wear consisted of a ratty U.S. Open T-shirt from 1993 (the year I graduated from high school) and a pair of worn, cut-off cotton bicycle shorts from roughly the same era. I am flinching just describing this ensemble in type, but it never really bothered me before: I mean, who cares what you look like when you’re sweating it out at the gym, right?

Well, I just started running again for the first time in a while and, after noticing all of the fitted, fashionable get-ups blowing by me on the towpath, I decided to visit one of those bastions of sleek, stylish and costly athletic apparel that have inspired cultlike devotion, to try some of their gear. And I must say that I totally get the hype now. For one thing, I look about five pounds thinner and more in shape in my shiny new black running tights, which seems worth the price of admission alone.

But does this new and improved exercise attire — with such thoughtful little details as chafe-resistant flat seams, body-mapped perforation for airflow, built-in reflective designs, anti-stink fabric and a nifty little pocket for my iPod, credit card and keys — actually help performance?

“There’s no doubt that better-quality, more comfortable athletic clothing can have benefits, from both a physical and psychological standpoint,” says exercise physiologist Thomas Altena of Missouri State University. “It’s like cars: Until you get into the high-tech gear, you don’t really know what you’re missing.”

To start, the right material will help regulate your body temperature. This can affect heart function, which in turn influences how difficult you perceive an activity to be, says exercise physiologist Delia Roberts, a fellow with the American College of Sports Medicine.

Does new and improved exercise attire actually help performance? (istockphoto)

“If you want one item that’s guaranteed to decrease [athletic performance], that’s letting your body get too hot,” she says, explaining that the newest generation of synthetic fabrics such as polypropylene, along with old standbys such as merino wool, wick sweat away from the skin and allow it to evaporate, for a cooling effect. Cotton, on the other hand, “will absorb moisture and wetness and keep it close to the skin,” which can be uncomfortable, and cause chafing, blisters and other skin irritations.

Roberts adds that compression garments, which claim to improve blood circulation to a particular area of the body such as the legs, may also boost athletic performance — although probably not for the reason manufacturers state.

She said that according to research published this year in the journal Medicine & Science in Sports & Exercise, there’s no evidence that positive effects of compression tights are due to increased blood flow; instead, it appears that any benefits may stem from the fact that these tight pants, shorts and other clothes reduce muscle vibration and provide additional muscle support during a workout.

And the workout-wear design innovations — such as those flat seams, fabrics that don’t smell (no matter how hard you sweat) and well-thought-out pockets — can help make you more at ease on your bike or the treadmill, allowing you to focus more on the task at hand and to persevere, Altena says.

“If you’re uncomfortable while you’re working out, you’re probably not going to do it the next day and the day after that,” he explains. “Spending some extra money [on better gear] doesn’t necessarily mean you get a better product, but oftentimes you get a better experience, which means you’re more likely to keep at it.”

Indeed, as I discovered, chic, flattering togs can do wonders for your confidence and long-term drive. “In order to stay motivated, you’ve got to set up circumstances really well for yourself, so you look forward to exercise and enjoy it, and clothes can really help,” says Washington psychotherapist and personal trainer Jane Baxter, who has written a book about using exercise to help manage depression. “If something fits and feels great and you look great in it, especially before you reach your fitness goal, you’re much more likely to put it on and go to the gym.”

So how do you find gear that will keep you cool, comfortable and feeling your best? Given the high price tags on some of this stuff, it’s wise to look for a few high-quality pieces made of quick-drying, moisture-wicking fabrics that work for your sport of choice and to pay attention to layering properly as we head into colder months. Clothes should be fitted to avoid chafing but not so tight that they’ll rub and be uncomfortable, says Altena, who adds that his No. 1 priority is decent athletic socks with a fair amount of polyester, which wick moisture and prevent blisters, sores and bruising, and “can make a bad pair of shoes work well.”

And you don’t have to break the bank by going to a speciality store. “There are a lot of [apparel] options out there now, at all different price points,” says Georgetown personal trainer Steve Kostorowski, who adds that you can make your new gear last longer by “babying” it — in particular, by avoiding fabric softeners that can interfere with features such as moisture-wicking and by hanging it to dry.

But, as Althena says,“The most important thing is obviously getting out there and being active, no matter what you’re wearing,”