In this paper we propose to use context information obtained from body-worn sensors to mediate notifications for a wearable computer. In particular we introduce a model which uses two axes, namely personal and social interruptability of the user in order to decide both whether or not to notify the user and to decide which notification modality to use. Rather than to model and recognize the complete context of the user we argue that personal and social interruptability can be derived directly from various sensors by the combination of tendencies. First experimental results show the feasibility of the approach using acceleration, audio, and location sensors.