Debunked Myths

The '70% water' statistic represents a rounded-up simplification that became entrenched in common knowledge. The more accurate average for adults is 50-60%, and this percentage fluctuates significantly based on individual factors. Body composition plays the biggest role—fat tissue contains only about 10% water, while muscle is 75-80% water.

This means a lean, muscular person will have higher water percentage than someone with more body fat. Age dramatically affects hydration too: newborns are about 75-78% water, reflecting their developing systems, while elderly adults may drop to 45-50% due to natural muscle loss and reduced fluid retention.

The '70%' figure likely originated as a rough average for a standard male reference model and stuck due to its simplicity. The reality reveals our hydration as a dynamic state intimately tied to our body's changing composition throughout life, not a fixed biological constant.