Power gating is an effective way to reduce leakage power. This technique uses high Vthtransistors, called sleep transistors, to turn off the power supply. However, sleep transistors suffer from the bias temperature instability (BTI) effect, resulting in an increased Vth, and reduced reliability. This paper proposes two BTI-aware sleep transistor sizing algorithms to reduce the total width of sleep transistors based on the distributed sleep transistor network structure. The proposed algorithms reduce total width by more than 16.08%. More area can be reduced if the BTI effect on both sleep and cluster transistors is considered.