That's a solid standby uniform but you're right, you need some gym clothes. You want to look presentable at the gym, but not like you're trying to look good. Invest in some quality basics—plain T-shirts, shorts that don't extend past your knees, a sweatshirt that doesn't add too much bulk and some lightweight shoes. Then pack them all in a discreet, but durable bag. You've likely noticed pro athletes and other guys at the gym wearing compression clothing under their gear—and for good reason. A study by the International Journal of Sports Medicine confirmed that those in compression tights had better circulation and used less energy than those without. They've also been shown to keep muscles warmer and looser. After all, it won't matter how good you look if you pull a hamstring.
$50 by Alternative Apparel
$22.50 by Lands' End
$85 by Nike
$18 by American Apparel
The percentage of adults who report they are not physically active.
(Source: President's Council on Physical Fitness)