Various studies on hydration and its benefit for health, cognitive function and productivity are largely increasing in the last decade. Publications, scientific meetings and popular publications about hydration in the mass media are also increasing. In line with the advances of science and technology on hydration, the term of healthy hydration emerged in many publications and discussions.
The adjective word “healthy” has appeared many times in various publication and programs associated with healthy life, e.g. healthy lifestyle, healthy sleep, healthy cooking, healthy eating, healthy diet, healthy breakfast, et cetera. The terms healthy hydration was introduced, but there is no clear definition about it yet. Moreover, we did not find any guideline about healthy hydration during our online searching in the Internet, neither for healthcare personnel nor the community.

We define healthy hydration simply as the adequate amount or volume of water that is required for a healthy life. Scientifically, healthy hydration is the sufficient amount or volume of water and is qualified to meet the requirement for healthy life, as indicated by the normal body plasma osmolality. Water quality in this definition means the quality of consumed water from the physical, chemical, and biological aspects, which will not be harmful for human and is regulated with certain standards from the authoritative body. The physical characteristics include odor, color, taste, and temperature. The chemical characteristics are acidity (pH), mineral content, electrolytes, sugar, and hazardous substances, while the biological parameters consists of the type and amount of interfering micro-organisms or pathogens. Previously, we have issued several books and publications about hydration, i.e. Water for Health, Water for the Children and Teenagers, Water for the Elderly, and Water for the Pregnant and Lactating Mothers. However, we have not written anything about healthy hydration. Therefore, considering the aforementioned things, we decided to write this book as a reading material and reference for healthcare personnel in implementing health hydration in Indonesia.