Extra fluids don’t fight colds

There’s no evidence that drinking extra fluids when you have a respiratory illness helps you recover. It may actually be harmful, warns a recent review in the British Medical Journal. People with pneumonia or bronchitis may secrete a water-retaining hormone that along with copious fluid intake could dangerously lower their blood sodium level. Whether that risk applies to upper-respiratory infections such as colds or flu is not clear. But drinking enough fluids--the usual 9 to 13 cups a day for most adults--is crucial when you’re sick, to prevent dehydration and maintain optimal functioning.