Heat-related mortality is of growing concern for cities faced with the combined effects of increasing heat-wave frequency and intensity and stronger urban heat islands (UHI). In cities around the world, high air temperatures have been found to have strong repercussions in terms of heat-related mortality for populations aged 65 years and older, especially nighttime temperatures. In response, many measures have been proposed to counteract the effects of UHI such as cool roofs and materials or urban greening. While these approaches are promising and are rightfully explored, behavioral adaptation measures have not received as much attention. Given the importance of nighttime temperatures on heat-wave mortality and the importance of sleep quality for individuals to recover from intense daytime heat exposure, adapting sleeping habits to reduce sleep time exposure to intense heat may help reduce the health impacts of heat-waves. In this paper, outdoor and indoor temperature measurements conducted over the summer of 2015 in the bedrooms of two apartments in Paris, France are analyzed. The potential for this kind of behavioral adaptation to reduce occupant exposure to high sleep time temperatures is quantified and discussed. The policy implications of our findings and their practicality are also mentioned. (C) 2016 Elsevier B.V. All rights reserved.