The D-band among all sub-THz and THz radio frequencies is foreseen as the first one to be utilized for communications. Such high frequency communication links are particularly susceptible to shadowing events, e.g., caused by the human body. In this paper we present results of a D-band channel measurement campaign, which was conducted to characterize the impact of human blockage, with a focus on the excess attenuation and temporal evolution of human body shadowing. The attenuation caused by single-person blockers with different physical characteristics was measured with human frontal and lateral crossing the line-of-sight link. Predicting results of two knife-edge diffraction models are compared with the measurement curves, which both underestimate the attenuation levels especially for the volunteer with larger size. Meanwhile, we quantify the deep fading duration varying with the fading depth, which helps to optimize the beam alignment strategy in order to maintain the sufficient signal-to-noise ratio when the dominant path is heavily obstructed.