MILLINOCKET — A former Boston College cross-country runner has traversed the 2,190-mile Appalachian Trail in record time after a sleepless, 37-hour sprint to the top of Maine’s Mount Katahdin.

Joe McConaughy, known on the trail as “Stringbean,” reached the mountain summit Thursday, finishing his trek in 45 days, 12 hours, 15 minutes. He averaged about 48 miles daily.

The 26-year-old told The Boston Globe that he loves running, hiking, the outdoors “and pushing myself.”

His unofficial time beats the previous best by about 10 hours and McConaughy says he did it without outside help. He says he mailed his food and supplies before starting in Georgia.

The Seattle native used global-positioning data and social media time stamps to back his claim. The Appalachian Trail Conference doesn’t keep official records.

McConaughy is part of a growing sport of speed-hiking or running long-distance trails with the aim of setting new records, referred to as “fastest known times,” or FKTs, because there is no regulatory body that maintains the official records.

By finishing his trek in 45 days and 12 hours, McConaughy surpassed the previous record set just last year by ultrarunner Karl Metzler. And Metzler beat by roughly 10 hours the record set by Scott Jurek just one year earlier in 2015.

Unlike Metzler and Jurek, McConaughy said his hike was “self-supported,” meaning he did not rely on others waiting to supply him with food, water or other assistance along the way.

The increasing frequency of “supported” hikes – sometimes involving corporate sponsors and video crews – became a flash point during Jurek’s 2015 hike. Baxter State Park officials issued him citations for excessive celebrations (including alcohol) atop Katahdin and hiking in too large a group, charges that Jurek disputed while criticizing park officials’ handling of the situation. Jurek ultimately only had to pay a fine for alcohol consumption.

But the incident burst into the open a long-simmering frustration among Baxter State Park officials about the amount of resources and staff time consumed by the steadily increasing numbers of Appalachian Trail “thru hikers” in the wilderness park.

According to The Boston Globe, McConaughy celebrated the completion of his trek with his girlfriend and a close friend, who had hiked to Baxter Peak ahead of him. He said in a post on his Instagram page that he was also greeted atop Katahdin “by 70 mile winds, hail, rain, mist, endless boulder scrambles.”

“After a 37 hour push, I managed 110.8 miles straight to do what I had to do, more than I have run at once by almost 50 miles,” he wrote. “I honestly don’t know what to say. I’m am in shock and pain, joyful and thankful, humbled and tired, in disbelief and exhilaration. I will be forever perplexed and appreciative of what the wilderness brings out in myself and others. I hope anyone watching is at least inspired to become more involved in the outdoors.”

Staff writer Kevin Miller contributed to this report.