It’s an important question for everyone, but it’s even more key for older people – and still more relevant for older people who are physically active.

The common refrain is usually that people should drink 8 ounces of water 8 times a day. Another common guideline is half of one’s bodyweight in ounces. For example, a woman that weighs 150 lb. should drink 75 onces over the course of the day (just over 2L).

Those are each good baselines to start with, but it varies for everyone, especially for older people who exercise and enjoy being outdoors.

Why are older people more apt to get dehydrated?

Simply put, we lose our ability to feel thirst as we age, and our kidneys often decline in function. For some seniors, just getting up and down for a glass of water can be difficult, and others can easily forget, with or without dementia. Further, some medications add to the problem with common side effects.

Older people who exercise can also have a heightened risk of getting dehydrated. You might sweat more than you realize, causing your body to hold onto water it needs for basic functioning – which can lead to cramped muscles.

Dehydration can also cause dizziness, headache, impaired memory and concentration, and constipation.

To be sure you’re getting enough water, drink plenty before, during and after exercise. Add a sports drink with electrolytes and sodium, which will replace what your body loses. Fruit and vegetables generally have a high concentration of water, too.

Just remember to drink up – and never wait until you’re thirsty.

-Shelley Turk, Functional Aging Specialist and owner of ProActive Fitness