Notifications for visual and auditory modalities from smart phone have some problems. For the visual modality, the user needs to actively control his or her viewpoint toward the phone. For the auditory modality, the user may not hear the notification sound because it is drowned out by surrounding sound. As a solution to the problems, we have proposed a subtle notification system that uses wind and scent to notify users of less important notifications and identify the user’s awareness of the notification based on changes in the user’s physiological signals. In this paper, we conducted an experiment to measure and analyze physiological signals when subtle wind and scent stimuli were presented to participants performing a reading task, in order to design the proposed system. The results show that the wind stimulus caused a change in skin conductance and the scent stimulus caused a change in the amplitude of respiratory movement. This suggest that even such weak and invisible stimuli are noticed by a user performing a task and are reflected in the user’s physiological responses.