Fastest 100 miles on a treadmill (female)

The fastest 100 miles on a treadmill (female) is 12 hr 47 min 10 sec and was achieved by Ashley Paulson (USA) in Boston, Massachussets, USA, on 18 April 2026.

The fastest 100 miles on a treadmill (female) is 12 hr 47 min 10 sec, achieved by Ashley Paulson (USA) in Boston, Massachusetts, USA, on 18 April 2026. Ashley took on the challenge in the middle of the Boston Marathon Expo, running in full view of thousands of marathon entrants collecting their race bibs, a deliberate choice to turn the notorious monotony of treadmill running — the "dreadmill," as she calls it — into something energizing rather than draining. She prepared meticulously in the lead-up, training extensively on the treadmill itself and fine-tuning her nutrition, hydration, and even her bathroom-break routine, practising how to safely pause the machine and let it fully stop before stepping off. Beyond the record itself, Ashley hoped her public attempt might inspire at least one expo-goer ahead of their own marathon, while the high-visibility setting also brought media coverage that helped document and validate the feat for GWR.