An older woman is gardening in the direct sun for three hours without any rest. She suddenly feels weak and dizzy before she faints. She is taken to an emergency room where the doctor suspects she is suffering from dehydration. This is a common problem in older people because:
The reason for common dehydration is older people is that they loose sensitivity to their feeling of thirst: they don't feel it as strongly and because of this, they might consume less liquids than then need.