Sarah Thomas, a 37-year-old marathon swimmer from Colorado has just broken a world-record: swimming across the English Channel four times non-stop in 54 hours. According to NPR, four swimmers had previously crossed the 21-mile-wide Channel three times without stopping. (Watch The Guardian video above.)

Last year, Thomas finished up treatments for breast cancer, during which she swam to help cope with the debilitating effects. She dedicated her epic exploit to “all the survivors out there.”

“This is for those of us who have prayed for our lives, who have wondered with despair about what comes next, and have battled through pain and fear to overcome,” Thomas wrote. “This is for those of you just starting your cancer journey and those of you who are thriving with cancer kicked firmly into the past, and for everyone in between.”

According to the BBC, the swim was supposed to be around 80 miles long, but ended up being closer to 130 miles. Thomas had to contend with a strong current constantly pushing her off course, fluctuating tides and stomach aches. Plus, a jellyfish stung her in the face. But she persevered. Thomas’s mother Becky Baxter says her daughter is “a freak of nature.”