Peterborough MP Fiona Onasanya said she has worked 120- hour weeks during her first year in Parliament - which equates to more than 17 hours a day for seven days.
The Labour MP made the comment in a four minute video posted to her Facebook page last week.
The 120 hour working week does not include travelling.
Ms Onasanya said in the video: “So it’s been a whole year since I was elected as the MP for Peterborough. It’s been really surreal - I don’t think I will ever get used to it.
“It’s been hard finding your feet as a new MP - no one can really prepare you for it. There’s never a straightforward day.
“I would say you work between 80 and 120 hours a week. Your days, if there was a standard, are about 18- hour days, but I really, really, have enjoyed it and I feel honoured.”
The long weeks include staying late to debate and vote on important legislation, she said.
Ms Onasanya also spoke about Brexit in the video, describing herself as a Remainer who wants to make sure the UK leaves the EU “safely”.
She said: “For example, if you wanted to go outside and it was pouring down with rain and you’re going to get soaked, my advice would be ‘stay inside until it stops raining - it’s better inside and it’s dry’.
“But you’re adamant you want to go outside. My duty then is to get umbrellas, wellies and a rain mac so that actually you stay as dry as possible. And you were like ‘oh, okay’.
“That’s how I feel about Brexit. My job is to look out for the constituents of Peterborough. We need to get a deal. We’re leaving - I’m not saying that we’re not. I’m saying how we leave needs to be looked into and that’s why I vote in the ways that I do.”
Ms Onasanya, who won the seat from Conservative Stewart Jackson last year, also said her “immediate focus” is looking at “inhumane” business practices.