The Kepler satellite has discovered thousands of planetary candidates, and confirmed hundreds of those. Among these confirmed planets, several rank highly on scales of 'habitability', including well-known objects such as Kepler-22b, Kepler-61b and others. We have been working on studying the host stars of these habitable planets, with the aim of investigating the effects of the host on habitability. Here we will present studies of the activity levels of the hosts, measured through several photometric proxies using the Kepler data. These measurements of activity impact strongly on putative habitability, being an indication of the levels of radiation and coronal mass ejections experienced at the planet's orbit.