July 2023

HYDRATION

Staying hydrated is as key to health as staying active, eating a healthy diet and getting good sleep, but what does “being hydrated” really mean?  And how do you know if you’re consuming enough fluids to stay adequately hydrated?  Here is everything you need to know about water.

Water makes up the largest component of the body, approximately 60% in adults and 70% in children. The body loses water each day through urination, as well as breathing, sweating (even if you don’t break a sweat), metabolism and excretion of waste, so replacing this water is critical. Rehydrating to replace losses keeps us from feeling sluggish but it also keeps many other things smoothly running, from digestion to temperature regulation to brain function, as well as being the base for every fluid in the body including blood. Thirst is a tool the body uses to prevent us from becoming severely dehydrated. When water intake hasn’t kept up with losses, the concentration of sodium in the blood increases. Sensors detect this and notify the brain which in turn triggers the release of hormones to slow water loss and initiate thirst to prompt us to seek water. You’re already mildly dehydrated when you start to feel a little parched though, so thirst shouldn’t be used as the sole indicator for when to drink water. And because the thirst sensation diminishes with age, it’s even more important for older adults to hydrate regularly and not wait until they feel thirsty.

How much do I need?

There is no across-the-board answer because hydration needs greatly vary by individual. The goal you commonly hear is 64 ounces (8 8-ounce) glasses of water per day. This is a good place to start if you aren’t already consuming adequate water, but research suggests that most people need more.  The guidelines still need to be adjusted based on factors such as these:

Environment: Needs increase when you live in an area that is hot, humid or dry or one at a higher altitude. Needs also increase in the hotter months of the year, regardless of geographical location.

Daily activity: Those getting activity during the day, no matter if it’s related to work childcare, or household chores, will have higher needs than those sitting or sedentary for several hours.

Exercise: Fluid needs increase during and after exercise, even if you don’t break a sweat. And when you do, the greater the perspiration, the greater the need for fluid replacement.

Health status: Vomiting and diarrhea increase the need for fluid replacement. Fever also increases fluid needs due to the increase in body temperature. Pregnant women, those breastfeeding and individuals on certain medications also have higher fluid needs.

How to meet your fluid needs

If consuming 2 liters of water per day seems daunting, here is some good news. Some other fluids as well as some foods count toward your daily water intake. Here is a look at what counts, as well as some beverage categories to avoid when you’re trying to stay hydrated.

All types of water: It doesn’t matter if it’s from a well, bottle or tap, water is considered the ideal hydration source. Sparkling water included, but not to the exclusion of plain water. The reason for this is that sparkling water is alkaline, and too much may dilute stomach acid to the point that some minerals and other nutrients aren’t able to be made bioavailable to be absorbed later in the digestive tract.

Milks and juices: These beverages minimally contribute to total daily water intake because while they do contain water, they also contain calories as well as nutrients that must be metabolized and absorbed.

Foods: Approximately 20% of an individual's daily water intake comes from food. While all foods contain some water, fruits and vegetables contain the most (90-99%), so eating more produce not only reduces disease risks, but also boosts water intake. Other foods comprised of 60-80% water include yogurt, cottage cheese, seafood, pasta, chicken, and beans.

Beverages to avoid or minimize: Alcoholic drinks and caffeinated beverages are categories that don’t count as hydration sources. In fact, they contribute to dehydration. Alcohol causes the body to lose water through its diuretic effect, and caffeine as well causes diuresis.   Add 1-2 glasses of water over and above the recommended amount for every alcoholic or caffeinated beverage you consume.

Top 10 Reasons to Stay Hydrated

Even mild dehydration impacts our daily productivity, energy and mood, but there are plenty of other reasons to stay hydrated.

• Improves mood and memory. Even mild dehydration impacts working memory, decreases motivation and focus, and leads to changes in mood.
• Protects heart health. Dehydration is associated with an increased risk for heart disease and heart failure.
• Supports the kidneys. Water plays a critical role in removing waste from the blood via urine, but when you are underhydrated, urine production slows, and the kidneys can’t remove those wastes.
• Enables immune system. Adequate hydration is essential for the immune system to work effectively.
• Promotes a healthy weight. Drinking water helps to decrease appetite. It also can result in less food intake when consumed before a meal.
• Prevents headaches. When the body is dehydrated, the brain contracts, putting pressure on nerves and causing pain, so even those who don’t have regular headaches may benefit from some extra hydration when a headache sets in.
• Lubricates and protects joints. Just like other fluids in the body, synovial fluid (and its cushioning) decreases as dehydration progresses. Daily hydration is also vital for maintaining healthy, pain-free joints since cartilage is approximately 85% water.
• Decreases risk of type 2 diabetes. Dehydration is considered a risk factor for the development of metabolic syndrome and diabetes.
• Keeps you looking good. While it won’t prevent or get rid of wrinkles, a glass of water (or two) can add plumpness to skin and so wrinkles appear less pronounced or noticeable.
• Lessens risk of early death and chronic disease. It appears that regularly getting dehydrated takes a toll, speeding up the aging process and increasing risk for chronic diseases like heart disease, diabetes, dementia and obesity.

Carolyn Williams, PhD, RD