HYDERABAD: For decades, the ‘8×8’ rule — drinking eight glasses of eight ounces of water daily — was considered the benchmark for hydration. However, health experts now say the one-size-fits-all approach is outdated.
According to the 2024 Dietary Guidelines for Indians issued by the Hyderabad-based ICMR-National Institute of Nutrition, hydration needs vary widely based on climate, lifestyle and individual factors. The guidelines recommend a total daily fluid intake of about 3.7 litres for healthy adult men and around 2.7 litres for women, including fluids from all sources such as milk, tea and coffee, not just plain water.
Dr Sudhir Kumar, a neurologist and public health advocate, said there is no scientific evidence supporting the eight-glasses-a-day rule for everyone. “The human body has a highly sophisticated system to regulate fluid balance, and thirst is usually the most reliable signal indicating when water is needed,” he said.
Senior doctors cautioned that forcefully consuming water to meet arbitrary targets could lead to overhydration and dangerously low sodium levels.
The guidelines also note that hydration depends on diet, physical activity, body weight and environmental conditions. Many fruits and vegetables, such as cucumbers, are nearly 90% water.
Experts advise monitoring thirst cues and urine colour, with pale yellow indicating adequate hydration, while darker shades signal dehydration. Overall, specialists say hydration should be seen as a balance of fluids from both food and beverages, making the ‘eight glasses a day’ rule more myth than mandate.