Water is essential for life; every cell in your body needs water to function properly. It makes up about 75% of body weight in infants and 55% of body weight in the elderly. For something as seemingly simple and vital as drinking water, plenty of myths and misconceptions exist about its possible benefits and harms.
1. Everyone needs to drink eight glasses of water per day.
Myth. There is little scientific basis for this statement. Actual fluid needs typically depend on body size and energy expenditure (i.e. physical activity). Fluid intake, driven by thirst allows maintenance of hydration and total body water at normal levels.
2. Drinking water flushes toxins from your body.
Fact. If you are not properly hydrated, your kidneys don’t have the right amount of fluid to remove metabolic wastes as efficiently. In other words, lack of water causes the body to hold in toxins rather than expelling them as required for proper health.
3. If you are constipated… increase fluid intake.
Myth. The evidence suggests that increasing fluid intake as a treatment for constipation is only effective for individuals who are dehydrated and is of little utility to those who are sufficiently hydrated.
4. Drinking water helps you lose weight.
Fact. Drinking water does not necessarily trigger weight loss but it can replace other calorie-containing beverages in the diet and thus reduce your overall energy intake. Drinking water before consuming food can also make you feel fuller, causing you to eat less.
5. Water in caffeinated beverages (e.g. soda, coffee and tea) does not “count” towards keeping you hydrated.
Myth. There is no evidence that the diuretic effects of caffeinated beverages cancel out their hydration effects.
6. It’s possible to drink too much water.
Fact. Individuals with certain health complications such as high blood pressure and/or swelling of the lower legs (i.e. edema) need to avoid excess water. If you have had a kidney transplant you should also talk with your doctor about your fluid intake.
7. Yellow urine is a sign of dehydration.
Myth. Yellow urine can be a sign of dehydration but not all yellow urine is a cause for alarm. Other factors such as taking multivitamins or other dietary supplements containing high levels of B-vitamins can make your urine yellow.
8. Dehydration can impair cognitive function.
Fact. Studies have shown that when individuals are dehydrated by approximately 3%, performance was impaired on tasks involving visual perception, short-term memory and psychomotor ability.
9. Fitness increases your risk of dehydration.
Myth. Fitness can actually reduce your risk of dehydration. Fit people of any age sweat more, keeping the body cool, and have more diluted sweat, losing fewer electrolytes as they perspire.
10. Elderly individuals should be more aware of their body’s fluid needs.
Fact. Older people often have a reduced sensation to thirst, so it’s easier to miss warning signs of dehydration. Older people are also less able to compensate for the increased blood thickness which results from water loss through sweating. So it’s increasingly important to pay attention to your body’s fluid needs as you age.