Mobile and wearable devices are being increasingly developed for health care purposes. Mobile health (mHealth) data encompasses personal health data collected from sensors and mobile applications. Standardizing mHealth data and metadata will improve the ease and alignment accuracy of aggregating data across multiple mobile health sources (semantic interoperability) and will reduce the costs of using this data for biomedical discovery, improving health, and managing disease. Specifications for standardized representations of quantitative sleep and physical activity measures, minimum metadata, and subjective reports (surveys) are defined by this IEEE 1752.1 standard. The purpose of this standard is the providing of standard semantics to enable meaningful description, exchange, sharing, and use of such mHealth data. Data and associated metadata complying to this standard will be sufficiently clear and complete to support their use for a broad set of consumer health, biomedical research, and clinical care needs.