Drink right amount of fluids
DEAR DOCTOR K: I’m in my 80s. At my last checkup, my doctor emphasized how important it is to stay hydrated. Can you explain why?
DEAR READER: Drinking fluids is crucial to staying healthy and maintaining the function of every system in your body. That includes your heart, brain and muscles. Among other things, fluids carry nutrients to your cells. They flush urine and bowel movements, both of which contain body wastes, out of your body.
If you don’t drink enough fluids, you run the risk of dehydration. This happens when your body loses too much water — through sweating, for example. Warning signs include weakness, low blood pressure, dizziness, confusion, or urine that’s dark in color. Even minimal dehydration can reduce your physical and mental capabilities.
Your body is very good at keeping you from becoming dehydrated. When the fluid in your body starts to get low, your kidneys make less urine (assuming your kidneys are healthy). However, in hot weather your body sweats — and you can lose a lot of fluid that way. The reason your body sweats is that the evaporation of the sweat from your skin cools the body.
Older adults like you are at particular risk of becoming dehydrated. That’s especially true during summer when it’s hotter and people perspire more. I spoke to my colleague Dr. Julian Seifter, a kidney specialist and associate professor of medicine at Harvard Medical School. He explained that older people don’t sense thirst as much as they did when they were younger. Or age may have weakened the ability of the kidneys to hang on to water. In particular, your heart, brain and kidneys are more vulnerable to the low blood pressure that often accompanies dehydration.
But it’s not only older adults who run the risk of dehydration. And it’s not just a summertime problem. Working outside, exercising or just enjoying the sun in any season can speed up the loss of body water. Illness with fever, diarrhea or vomiting can lead to dehydration. Anyone who is on a medication that may cause fluid loss, such as a blood-pressure-lowering diuretic, should be careful. And women who are pregnant and lactating require more fluids.
Water is the best fluid for hydration. It has no calories, sugar, salt, coloring or preservatives. Healthy people should drink about eight 8-ounce glasses of water per day — but not all at once.
Here are some tips for staying hydrated:
n Drink a glass of water when you first get up.
n Enjoy an herbal tea in the afternoon or evening.
n Carry water with you if away from home for long periods.
n Drink before you get thirsty.
n Sneak in some extra fluids by eating water-rich foods such as salads and fruit.
It’s possible to take in too much water if you have certain health conditions. These include kidney, liver or heart problems, as well as thyroid disease. You may also need to watch your fluid intake if you’re taking an NSAID drug, opiate pain medications or some antidepressants. Check with your doctor to make sure you’re getting the right amount.
(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)