Physical fitness, diet and mental stimulation all contribute to good brain health. But you also need water — and lots of it.
On average, the human body contains about 60 percent water. Nearly all bodily systems depend on it, including the brain.
“The brain is one of the major users of energy in the body,” says Dr. Brendan Kelley, a neurologist at Parkland Hospital and an associate professor of neurology at UT Southwestern Medical School. “There’s a lot of metabolic activity going on in the brain and water is really critical to making sure those biochemical reactions are taking place appropriately and are regulated.”
Kelley says we lose about 80 ounces of water through our daily activities, so we should try to replace that much each day. But he adds that’s only one step to good cognitive health. Our overall lifestyle choices are equally important.
Interview Highlights
Importance of water to the body: Water is important for a multitude of functions in our bodies, such as lubricating our joints and maintaining our temperature. It’s also important for how our cells manage energy. The brain is one of the major users of energy in the body. There’s a lot of metabolic activity going on in the brain and water is really critical to making sure those biochemical reactions are taking place appropriately and are regulated.
If you don’t drink enough water: Several studies have found even mild levels of dehydration are associated with increased difficulty with our mental functions: some loss of mental clarity, difficulties with concentration. Some people may even manifest changes like feeling more down or depressed or having a quicker temper. We also recognize in many of our neurology patients that dehydration can be associated with an increased risk of having a migraine.
How much water you should drink: Most estimates say as we go through our daily activities we lose about 80 ounces of water per day. That’s from sweating, from water vapor that we exhale – kind of the normal body processes. To give a rough estimate of how much water intake we should be replacing each day, it would be about 80 ounces. Now, that can be included in water or other liquids that we might drink. The food that we eat also contains some water. But that’s roughly the hole we dig each day that we need to fill.
Tea, coffee, soda, fruit juices? Tea or coffee can work as a weak diuretic, making us lose some water when we go to the bathroom. They’re perhaps not as effective at replacing our hydration as water would be, but they are replacing some. Soda or juice may include other components like chemical additives or sugar or other things that we’re taking in along with it. And so it might not be ideal to use soda and juice as the primary source of fluid intake as we would be inadvertently taking in a lot more calories than we intended.
Water’s only one step to good brain health: The best evidence to date is emerging to identify not a single lifestyle choice that we make, but a pattern of lifestyle choices that is associated with retaining our brain health. Certainly maintaining good hydration is important in that, eating a healthy diet, getting regular physical exercise and mentally stimulating ourselves regularly are all important to maintaining good cognitive health.
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