The human body is made up of approximately what percentage of water by weight?

The human body is composed of approximately 60% water by weight. This percentage can vary based on factors such as age, sex, and body composition. For instance, infants have a higher percentage of water in their bodies, around 75-78%, while older adults may have lower percentages due to a decline in muscle mass and an increase in body fat.

Water plays a crucial role in numerous bodily functions, including regulating body temperature, aiding digestion, transporting nutrients, and facilitating chemical reactions. Understanding the concept of water composition is significant when considering hydration needs and nutritional requirements for optimal health and performance.