The human body is composed of 50 to 60% water but, from the age of about 60, that percentage decreases by about 5%, which is also one reason why more wrinkles appear with age.
The kidneys control the body’s water and electrolyte balance, and in older people they become less adaptable. They continue to excrete large amounts of water and sodium, even if insufficient water has been taken in.
They also react less to ADH, the most important neurotransmitter in the control circuit between the brain and the body’s water content. As a result, many older people simply forget to drink enough.
However, this knowledge is no help if people are deliberately drinking less because they suffer from incontinence or a weak bladder. This lack of fluids can have serious health consequences, which is why experts advise older people to do pelvic floor exercises and wear incontinence pads.