We propose a distributed and secure system that enables global & ubiquitous health monitoring. The biomedical data, collected by wearable sensors will be transmitted using cell phones towards the corresponding Health Monitoring Centers via various wireless networks. The security of personal medical data is paramount. Therefore, we propose a new scheme that enable security communications among cell phones and other wireless networks. In particular, we propose a hybrid authentication scheme that involves both the cellular network and the Health Monitor Centers. Therefore, we take advantage of the strong authentication and non-repudiation provided by the cellular networks. Consequently, our solution guaranties confidentiality, privacy and defences against denial of service attacks.