Despite all its simplicity, there’s something truly majestic about the power of water.
In its central role as a life-sustaining compound, it delivers untold benefits to the human body. It’s a joint lubricator. Thirst-quencher. Temperature-regulator. Protector of the spinal cord and tissues.
And it can even promote good heart health.
“We know that water intake is important for our bodily functions,” Thomas Boyden, MD, director of preventive cardiology at Corewell Health, said. “Good hydration in general keeps sodium levels down, and that can reduce pressure on the heart.”
A study by the National Heart, Lung, and Blood Institute aimed to expand on that insight: Researchers found that consumption of a proper amount of water may help reduce or even prevent severe heart problems.
The study reviewed the hydration habits and heart health of more than 11,000 adults ages 45-66, based on data from a 25-year period. The participants had no history of heart failure, diabetes or obesity when the study began.
Researchers looked at sodium levels in each person’s blood, also known as serum sodium. As the body’s fluid levels decrease, the serum sodium levels increase.
The study found higher serum sodium levels were associated with a greater risk of developing heart problems later in life. A greater intake of fluids could help lower the serum sodium levels.
While Dr. Boyden agrees that drinking water is good for health, he cautioned that the study’s findings aren’t conclusive.
“The NIH study does not yet prove correlation,” he said. “It is not a randomized study in which people are randomly assigned to drink more water.”
What we do know: Too much sodium can make it more difficult for your heart to pump blood. The heart can weaken or stiffen when sodium levels are too high, Dr. Boyden said.
And that can increase blood pressure.
Water helps the body function at optimum levels. By staying hydrated, you help ensure your body can properly eliminate waste through urination, bowel movements and perspiration.
Drinking an adequate amount of water can help reduce appetite and aid in weight loss, too, as well as improving function of muscles—including the heart muscle.
So what’s a proper daily amount of water for one person?
“On average, an adult should drink about 64 ounces of water a day, or 2 liters,” Dr. Boyden said. “An athlete—someone with a lot of physical activity—should drink more than that, depending on the activity. Water needs can vary with your health, your activity level and the climate where you live.”
You can also consume foods that have a high water content, such as fruits and vegetables. Watermelon, for instance, is more than 90% water by weight.
Keep in mind that your water needs will increase as the temperatures rise, or when you develop a fever or lose water from diarrhea or vomiting.
Underconsumption of water can lead to dehydration, which can lead to problems such as confusion, constipation, kidney stones and mood swings.
“Water has no calories,” Dr. Boyden said. “We often hear that athletes should drink sports drinks to replace the water they lose during activity and to replace electrolytes, but water is still the best option. Normal kidney function regulates the electrolytes in our bodies naturally, so it’s not necessary to have those.”
Sports drinks often have additives and sugars, which we don’t need, he said.
On the other hand, too much water can be a problem. Your kidneys may have to work too hard to eliminate excess fluids.
Symptoms of over-hydration can include cramps, weakness or headaches.
“Two liters—that’s the size of those big pop bottles—should be enough water for the average adult,” he says. “It is possible to drink too much water, but that’s rare.”
Men typically need to drink more water than women, although women who are pregnant or breastfeeding should increase their water intake. Our bodies also require more water when we are feverish or have an infection.
What’s a good sign your water intake is at a healthy level? You’ll rarely feel thirsty and your urine will be a light yellow or clear color.
When in doubt, meet with your doctor or a dietitian—they can help you determine if you’re getting an adequate amount of water.