Reddit founder Alexis Ohanian wants you to know that "hustle porn" — the fetishization of extremely long working hours — is bad.

Ohanian let his own mental health go when he built Reddit. He suffered from depression, he says, but worked instead of getting well.

"This is one of the most toxic, dangerous things in tech right now," he told Web Summit on Tuesday.

LISBON, Portugal — "Hustle porn!" exclaims Alex Ohanian, his voice booming through the 20,000-capacity Altice Arena. "Is this a thing in the European tech community? Or is this a US thing?"

The Reddit founder is standing onstage at Web Summit, the annual tech conference in Lisbon, and the audience is baffled.

"This is one of the most toxic, dangerous things in tech right now," he says. "This idea that unless you are suffering, grinding working every hour of every day, you're not working hard enough."

"It's such bulls---, such utter bulls---."

Ohanian is referring to the fetishization of extremely long work hours, typically by entrepreneurs or tech workers, who give up nights and weekends to code their software or build their businesses.

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Ohanian hates it. It was a recurring theme in his speech to Web Summit on Tuesday, titled "What I wish a VC had told me." The backstory, of course, is that Ohanian was given $12,000 at a Y Combinator event in 2005, told "good luck," and went on to launch Reddit.

Now — in addition to being executive chairman at Reddit — he is a general partner at Initialized Capital, his own VC firm. And he has advice to give about not working ludicrous hours that sacrifice your physical or mental health.

"It has deleterious effects not just on your business but on your well-being," he says. Ohanian is passionate about this in large part because he suffered from depression while building Reddit after his mother died.

"As entrepreneurs, we are all so busy 'crushing it' that physical health, let alone mental health, is an afterthought for most founders. It took me years to realize that the way I was feeling — when working on Reddit was the only therapy I had — was depression," he wrote earlier this year.

Ohanian has other advice to give, of course. But it was a theme that ran through his speech. Take care of yourself, because work is not a substitute for health: "Please do not succumb to hustle porn."