As the weather heat up, people start thinking more seriously about hydration. You might be more diligent about drinking water or carrying a water bottle with you. All well and good. But for older adults, hydration isn’t just for hot weather. Aging messes with our ability to regulate body fluids, so we all need to be more conscious about fluid intake, and not just rely on thirst.
A recent review article renewed my interest in this subject, which led me to wade through a heavy duty technical review of all the ins and outs of fluid balance in the elderly. The Good News: I read it, so you don’t have to. The Bad News: aging can disturb fluid balance in ways that compromise health.
It isn’t necessary to understand all the hormone, kidney, electrolyte and body composition changes that contribute to this phenomenon. One of the more basic take-away messages is that aging impacts our ability to experience thirst in response to fluid imbalance. In young people, a complex system of hormones creates the sensation of thirst in response to low body fluids. This system becomes less effective with age. Result: you might remain in a water deficit because your brain isn’t telling you to drink fluids.
How can you tell if you’re dehydrated?
Unless you’re hospitalized for some reason, you can’t depend on lab tests to show lack of fluid. The best you can do is drink sufficient fluids every day. How much? Again, all we’ve got is a few “rules of thumb” from medical and public health organizations. One common recommendation is 1 ml water per kcal eaten. If you consume about 1500 kcal per day, you’d want to consume at least 1500 ml of water, or about 6-1/2 cups. But this rule doesn’t take into account body size, just food intake, which could be constrained by dieting or illness. Another rule is 30 ml per kg body weight. So if you weigh 140 lbs, that means 1900 ml of water, or 8 cups, which is the amount we’ve been advised to drink anyway.
Frankly I’m more inclined to go with recommendations based on actual body weight. And if you have any specific medical condition that impacts your fluid intake, such as kidney disease or heart failure, you need to follow fluid restrictions set by your doctor.
For the typical healthy adult, there are several reasons you might need to boost fluid intake:
- Hot or extremely hot weather
- Living in a dry climate
- Activity that induces significant sweating
- Illness and fever that increase sweating
- Diarrhea or vomiting
- Alcohol consumption
- Medications that impact fluid status (you should receive info on this from your pharmacist or doctor)
Contrary to popular myth, coffee and tea are not dehydrating, although it’s certainly not advisable to depend entirely on either of those for your fluid intake.
Best Fluids and Foods for Hydration
Hydration isn’t just about drinking water. You can get significant fluids from foods and other beverages. Diversity your hydration choices to avoid boredom. Added benefit: fruits and vegetables come packaged with other nutrients.
- Plain Water – goes without saying
- Club soda or seltzer.
- Infused water – fresh herbs, sliced fruit and cucumbers are all great choices for infused water
- Milk
- Tea – herbal, black, iced
- Coffee
- High fluid fruits and vegetables: watermelon, other melons, lettuce, cucumbers, zucchini, citrus, pears, grapes, peaches, nectarines, tomatoes, pineapple, …
- Fruit juice
- Sports drinks — I’m not a fan of these, but in some situations, they do the trick. Plus they do come with added electrolytes, handy for people who sweat a lot. But in general, the average person shouldn’t depend on these for everyday hydration.
Not the best hydration choices
- Soft drinks — full of sugar or artificial sweeteners
- Flavored coffee or tea drinks — loaded with sweeteners, fat, protein
- Protein drinks — these are really more like a food or a meal than a beverage.
- Sweet tea — sugar!
- Beer or cocktails — alcohol. NOT for hydration.
Take Away Message
As you age, you can’t count on thirst to warn you when you need fluids. The best strategy is to drink fluids throughout the day and add high water foods to the mix. Keeping in mind: you might be just as prone to dehydration in winter as summer.
