At a time when “endurance running” no longer means mere marathons — and even 100-mile races are attracting the masses — Karl Meltzer, a former ski-resort bartender, has proved he can suffer longer and faster than almost anyone else.

When he staggered onto Springer Mountain in Georgia before dawn Sunday, Meltzer set a record for completing the Appalachian Trail. He covered the 2,190 miles over 14 states in 45 days 22 hours 38 minutes.

Meltzer, 48, is a little different from other titans of the newly booming ultra-running scene. He is six years older than Scott Jurek, who was featured in the best-selling book about almost-barefoot endurance running, “Born to Run” — and who set the former Appalachian Trail record last year (46 days 8 hours 7 minutes).