By Permanente Medical Staff
Water: We all know it’s good for us, yet most of us don’t know exactly why – and we don’t drink enough of it. But staying hydrated can have an enormous impact on your overall health. You lose water throughout the day in familiar ways like sweating and urination, but also through mundane functions like breathing. This lost water must be replaced to allow just about every part of your body to work as designed, from the smallest cell to the largest muscle.
But what, specifically, does water do for your body? How much do you need? And what are you risking when you try to get by on too little? These five elements of our health depend on water in ways you may not be aware of:
Energy: Physical and Mental
Your brain and muscles have very high water content, so it’s no surprise that your physical and mental energy can suffer when you don’t drink enough of the stuff.
Even mild dehydration causes brain tissues to shrink, which forces them to work harder just to perform at the usual level. This can leave you feeling fatigued, forgetful, and depressed. Dehydration can affect motor skills, attention span, concentration, and memory; some studies have pinpointed that vigilance and working memory are especially affected. Dehydration also causes tension and anxiety, and makes exercise feel more difficult.
On the flip side, staying hydrated helps us think, focus, and concentrate better, as well as stay more alert. It can even reduce the oxidative stress that sometimes occurs with high-intensity exercise.
But don’t wait until you feel thirsty to crack that water bottle. By that time, you’re already dehydrated, and therefore fatigued.
Water is crucial to every organ, but our kidneys are among those most in need of adequate water and most sensitive to dehydration.
The kidneys filter between 120 and 150 quarts of fluid every day. They need water because it helps dissolve minerals and nutrients, making them accessible to the rest of our body and helping to transport waste and toxins out of the body. When waste products and extra fluids build up, it can cause, among other conditions, kidney stones, which in turn can lead to chronic kidney disease.
Staying hydrated is also one of the simplest ways to reduce the risk of developing a urinary tract infection, which is the second most common type of infection and can cause permanent damage if it spreads to the upper urinary tract, which includes the kidneys.
Your kidneys are also responsible for maintaining the proper balance of electrolytes – such as potassium, phosphate, and sodium – which carry messages between cells in the form of electrical signals. If the kidneys are unable to maintain that balance, the signals can become scrambled, which can lead to seizures, involuntary muscle movements, or loss of consciousness.
At its most extreme, dehydration can cause kidney failure, which is potentially life threatening. Possible complications include anemia, damage to the central nervous system, heart failure, and impairments to the immune system.
Dehydration makes every organ work harder to accomplish its role. Another part of the body’s detoxification system, the liver, is less efficient if the blood becomes more viscous due to reduced water content. Dehydration can also cause restriction of the airways, making asthma and allergies worse; raise the risk of coronary heart disease; make the skin more vulnerable to disorders and premature wrinkling; and increase blood pressure by thickening the blood.
Water is essential to the process of digesting food, and keeps things moving by helping to dissolve fats and soluble fiber. Preventing constipation reduces the burden on the kidneys and liver by flushing waste products from our system. Dehydration can also lead to an overly acidic stomach, which can cause heartburn and encourage the growth of ulcers.
Staying hydrated can help the immune system to function at its highest level by optimizing all of the body’s systems. This helps in fighting off everything from common viruses and the flu to cancer and heart attacks.
Water supports the immune system by ensuring that the blood carries plenty of oxygen to all of your cells, helping them to function at their best. It also allows the cells to take in high levels of nutrients and to get rid of built-up waste, and it supports the production of lymph, which carries white blood cells throughout the body to fight disease. Water also moistens the eyes and mouth, helping them to repel dirt and pathogens.
Cartilage, which is the rubbery material that coats our bones and is found in joints and in the disks of our spine, is more than 80 percent water. So drinking enough water helps to keep the cartilage around our joints elastic, ensuring that the joints stay lubricated and protecting the spinal cord.
Chronic dehydration can make the cartilage less supple and weaken its shock absorption powers, which can lead to joint pain.
How Much Is Enough?
So how much water do we need? One longstanding rule of thumb has been “8 by 8,” which stands for eight 8-ounce glasses per day. The National Academies of Sciences, Engineering and Medicine recommends slightly more: 91 ounces (2.7 liters) per day for women, and 125 ounces (3.7 liters) for men from all sources – food and beverages.
Some people will need to take in extra water each day to compensate for fluid loss. This includes those who exercise heavily, and those suffering from a fluid-depleting illness such as fever, vomiting, or diarrhea. Women who are pregnant or breastfeeding need additional amounts of fluid to stay hydrated.
The best way to meet those targets is by drinking plain old water. If you are falling short, try cultivating the habit of bringing a water bottle to work, on errands, or on family outings. Choose water when eating out and in place of sugary and/or caffeinated drinks. Drink a glass of water with each meal and between each meal.
You can also get some of your water from broth soups and foods high in fluids, like tomatoes, watermelons, and spinach. In fact, food supplies about 20 percent of our total water intake.
Ultimately, aim to take in enough water each day so that you rarely feel thirsty and your urine is colorless or light yellow.
Staying properly hydrated is one of the easiest steps you can take to stay healthy. Start drinking enough water now to ensure that every system in your body operates at peak efficiency.
For more information about the benefits of drinking water, visit CDC.gov. To learn more about dehydration and electrolytes, visit the MAPMG health resource page.