Expert Q&A

Hydration: Are you drinking enough fluids?

I’ve noticed that as I’ve grown older I’ve felt less and less thirsty. How do I know if I’m drinking enough fluids?

-Clarissa from Vermont

Adequate hydration is essential for all bodily functions. Our bodies are made up of 2/3 water. All of us are guilty of forgetting to drink enough fluids during our busy days. And anyone can become dehydrated. However, people at particular risk include those who exercise in excessive heat, those who are ill, children and the elderly. As we age, our senses may become less sharp (think eyesight and hearing). The same may be true for one’s sense of thirst. The older we get, the less efficient our bodies become at cooling themselves, so proper hydration becomes even more important.

Is water the only drink good for hydration?

Some believe that, thirsty or not, we must force ourselves to drink more than 8 cups of water every day. In the past, most nutrition experts believed that caffeinated beverages “didn’t count” towards our daily fluid requirements. As a result, for every cup of caffeinated fluid you consumed you needed to drink 2 cups of non-caffeinated fluid to replenish the loss of fluids caused by caffeine’s diuretic effect. Recent research has shown that, in fact, caffeinated beverages can count towards your body’s daily fluid needs. (Coffee drinkers rejoice!) While that frees us up a bit from the “water rule,” it may encourage people to consume soda and coffee instead of water.

Water is still the healthiest beverage around. Die-hard water drinkers swear that they have clearer skin and enjoy better overall health by drinking plenty of water (constantly flushing out toxins caused by pollution and even those that occur naturally through our own metabolism).

How much do you need to drink?

But how much water is needed for sustaining our body’s chemical and metabolic activities? A good rule of thumb is to add a zero to your body weight. You need at least that many milliliters in a 24-hour period. For someone weighing 145 pounds, that’s 1450 milliliters. Most portable water bottles provide 16.9 fluid ounces to be exact, or 500 milliliters (ml). Two of those bottles provide 33.8 fluid ounces, 1000ml or almost 4 1/4 cups of water. Add another bottle for 50.7 fluid ounces, 1500 ml, or 6 1/3 cups of water. Drink more water if you exercise heavily and sweat, (2 cups per pound of water weight lost post-exercise) and consume other fluids and/or watery foods (fruits) for optimal health.

Your fluid needs depend upon your weight, level of activity and metabolism. Let your body be your guide. Make sure to be more aware of what and how much you drink as you age so that you are supporting your body’s basic fluid needs.

Michèle Turcotte, MS, RD/LDN
Contributing Expert

Have a question for our Experts? Send it in!