Personal Health Records (PHR's) and related services are emerging rapidly. Currently, most PHR's are isolated and do not communicate with other systems. Standards for interoperability exist, but they are oriented towards clinical applications. However, a substantial part of a typical PHR consists of non-clinical information such as a health diary. The present paper highlights the requirements related to exchanging non-clinical PHR information between services and shows how this information exchange can be accomplished. The approach utilizes a SOAP message for carrying the actual PHR content in a structure referred as Health Diary Entry (HDE) document. The HDE document provides mechanisms to bind the contents to external vocabularies and ontologies to achieve semantic interoperability. The approach was successfully tested in the context of an occupational health pilot, in which data contents from several health and wellness applications were merged into a common database.