Recent advances in hardware and telecommunications have enabled the development of low cost mobile devices equipped with a variety of sensors. As a result, new functionalities, empowered by emerging mobile platforms, allow millions of applications to take advantage of vast amounts of data. Following this trend, mobile health applications collect users health-related information to help them better comprehend their health status and to promote their overall wellbeing. Nevertheless, health-related information is by nature and by law deemed sensitive and, therefore, its adequate protection is of substantial importance. In this paper we provide an in-depth security and privacy analysis of some of the most popular freeware mobile health applications. We have performed both static and dynamic analysis of selected mobile health applications, along with tailored testing of each application's functionalities. Long term analyses of the life cycle of the reviewed apps and our general data protection regulation compliance auditing procedure are unique features of the present paper. Our findings reveal that the majority of the analyzed applications do not follow well-known practices and guidelines, not even legal restrictions imposed by contemporary data protection regulations, thus jeopardizing the privacy of millions of users.