The treadmill desk is a new human–computer interaction (HCI) setup intended to reduce the time workers spend sitting. As most workers will not choose to spend their entire workday walking, this study investigated the short-term delayed effect of treadmill desk usage. An experiment was conducted in which participants either sat or walked while they read a text and received emails. Afterward, all participants performed a task to evaluate their attention and memory. Behavioral, neurophysiological, and perceptual evidence showed that participants who walked had a short-term increase in memory and attention, indicating that the use of a treadmill desk has a delayed effect. These findings suggest that the treadmill desk, in addition to having health benefits for workers, can also be beneficial for businesses by enhancing workforce performance.