06/03/2015 10:55 EDT | Updated 06/03/2016 05:59 EDT

Millennials driving sweatpant sales, 'athleisure' fashion trend

Wearing comfortable clothing used to be synonymous with lounging around your home. Now, it's become fashionable.

In a recent online makeover segment, O magazine creative director Adam Glassman extolled the virtues of a trendy, everyday sweatpant. 

"They do look like a sweatpant, but they're skinny and they're sexy, and they're not like that kind of shlumpy thing."

That's right, sweats are in, provided they're more stylish than shlumpy. These form-fitted sweats often look like regular pants.

And consumers are buying. In fact, according to market research firm NPD Group, Canadian sales of sweatpants have risen close to 20 per cent in the last year.

Millennials are driving the torrid sales pace, with young men contributing heavily to the numbers, spending 40 per cent more on sweats than the year before.

It's an extension of what's known as the "athleisure" fashion movement, according to Canadian style expert Afiya Francisco.

Athleisure refers to comfortable, stylish clothes with an athletic function. Francisco says the athleisure trend began when popular designer Alexander Wang took the popularity of athletic clothing like yoga pants, and showcased similar designs in his shows. Since then, Francisco said, wearing comfortable clothes has become much more popular.

"In addition to your sweatpants it also extends to your footwear," she explained. "So gone are the heels and in are your Nikes and your other really cool sneakers. And in addition to that it goes as far as your undergarments, so... people are saying no more to the thongs and to the Spanx, and instead they're favouring the granny panties and the comfortable undergarments."

A recent New York Times report backs up that statement, saying sales of more comfortable undergarments are on the rise, while thongs are on the decline.

Francisco says the younger generation drives many fashion trends, and this particular set isn't interested in the old norms.

"This new generation, they don't want to be seen as trying too hard, they don't want to be seen as uncomfortable." Francisco said. "It's just actually not cool to have made too much effort, and these pieces inherently do that. I mean, some people are spending so much time to find the perfect fit and perfect cut jogger but the perception is that it is effortless, and I think that's what they're going for."

Of course, looking like you're not trying too hard can cost you a lot of money. Francisco said the new stylish sweatpants today can run you hundreds of dollars.

And while she's a bit suspicious of the motivations of some young people who want to look casual but spend a lot of money on their clothes, she believes there's a significant upside.

"It's not a super body conscious fitting look any more, and so if someone isn't necessarily showing off their figure, I think that that can give them a lot more confidence."