Dehydration can be deadly, and according to a new study published in the Journal of the American College of Nutrition, most people have a hard time figuring out the right amount of water their body needs to keep running. To make it easier, two researchers from the University of New Hampshire developed a simple tool to measure hydration and provide water intake recommendations for healthy, active individuals.

The amount of water someone needs to stay adequately hydrated depends on the body’s constant shifts in temperature and weight, the intensity and duration of exercise, as well as the meals consumed throughout the day. The human body is 66 percent water, but can fluctuate in a variety of different ways. It's confusing, but researchers think they have found two ways to avoid dehydration.

For the study, researchers found measured total water content in an individual’s body, which can vary between 600 to 900 milliliters, and filled in the gaps of what additional water the body needed. Next, they measured the amount of fluid the individual consumed from not only water, but also other beverages and food; then, how much was expelled from urination and defecation. They found that fluid intake can be measured by both liquid volume, like water, and loss through excretion.

"Fluid needs can differ greatly among individuals due to variation in the factors that influence both water loss and solute balance; thus, adequacy is consistent with a wide range of fluid intakes and is better gauged using hydration assessment methods," the researchers wrote.

Keeping the body in balance is key to hydration, because individuals can fall short and overdue their water intake. Simply asking yourself "Am I drinking enough?" is an easy, inexpensive way to determine if water intake and outake throughout the day is considered healthy, usually between 2.5 and 4 eight-ounce cups of water each day.

According to the Mayo Clinic, dehydration can cause some serious complications. If you don’t drink enough fluids when you exercise, you may end up perspiring too much and end up with heat cramps or experience a potentially life-threatening heat stroke. Swelling of the brain, also known as cerebral edema, may also occur, which forces the body to pull too much water back into your cells and swell or rupture the brain and ultimately damage cells.

Others who don't drink enough water may experience seizures. Electrolytes, like potassium and sodium, help carry electrical signals from cell to cell. If electrolyte levels are out of whack due to dehydration, then the signals can misfire and cause involuntary muscle contractions, loss of consciousness, and even seizures. But one of the most serious consequences of dehydration is hypovolemic shock, which is when low blood volume triggers blood pressure to plummet and decrease the amount of oxygen in the body. Kidney failure, coma, and death are also imminent for those who go without water for too long.

On the flip side, consuming too much water can kill you. Fatal water intoxication occurs when electrolytes are thrown out of balance, similarly to what happens when you’re dehydrated. Kidneys control the amount of waters, salts, and other liquids are filtered and expelled from the body. When a person drinks too much water in a short period of time, their kidneys can’t keep up. It becomes a struggle to sift through the blood and flush it back out, causing the blood to become waterlogged and throwing off the amount of salt. The excess water leaves the blood and enters the cells, which swell up like a balloon and causes a slew of similar side effects to dehydration.

Too much or too little water is dangerous and, in extreme cases, deadly. Just the right amount can help you maintain a healthy and active lifestyle.

Source: Cheuvront SN and Kennewick RW. Am I drinking enough. Journal of the American College of Nutrition. 2016.