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How much water do you need to consume in a day?

by Debra J. McGinley

Let’s talk hydration

How much water do you need to consume in a day? In order to answer this question, I need you to understand why it’s important to consume water in the first place.

Water is an essential nutrient in our diet, and it accounts for 60% of your body weight. All of your cells need water for proper function and structure. Water is contained in lean muscle, bones, and fat, in addition to fluids such as blood, gastric juices, urine and perspiration. Water lubricates joints and tissues, is involved in the regulation of body temperature, maintains healthy skin, and is necessary for digestion. Think of it this way: your body is your vehicle and water is its gasoline.


It scares me when I see influencers at the gym with their big plastic gallon water jugs and tight, lean bodies emphasizing this is the way to 6-pack abs. Unfortunately, this just isn’t true. I understand the need to stay adequately hydrated, however, there is zero science that supports the requirement at a gallon a day for everyone and such advice may put you at risk of overhydration.

Overhydration is simply the act of taking in more water than the body loses or utilizes. So, why is this a big concern? Overhydration disturbs electrolyte balance, meaning it decreases sodium levels in the blood to dangerous levels that can be life threatening. In fact, you will start experiencing symptoms of water intoxication after consuming 3-4 liters (101-135ounces, where a gallon is 128 ounces) within a few hours. Sodium is tightly regulated in our body for a reason; it plays a crucial role in blood volume and pressure.

Who is at risk for overhydrating? Endurance athletes such as those who participate in triathlons or marathons.

How do you know if you are overhydrating? Symptoms include drowsiness and fatigue, muscle cramping/weakness/spasms, vomiting or nausea, and headaches.


Dehydration occurs when we lose more water than we take in. Again, it disrupts the balance of minerals in the body, like sodium and glucose, affecting the way our bodies function. Dehydration can be caused by excessive heat, activity, and/or sweating, in addition to medication side effects. It can be caused through illnesses, like having a fever, vomiting, diarrhea, or having uncontrolled diabetes.

Dehydration can also be caused by alcohol consumption. Alcohol suppresses anti-diuretic hormone (ADH), which is a hormone that signals to the kidneys to reduce urination and reabsorb water back into the body. Without it, our bodies flush out more water easily. To prevent dehydration, consume water and food with an alcoholic beverage or limit consumption.

What are the signs and symptoms of dehydration?

  • feeling thirsty
  • strong smelling, dark yellow urine
  • urinating less frequently
  • feeling dizzy or lightheaded
  • feeling tired
  • dry, cool skin
  • a dry mouth, lips and tongue
  • sunken eyes
  • muscle cramps

Mild dehydration can effect blood pressure and heart rate. Remember, sodium helps to tightly regulate blood volume and blood pressure. So too much or too little water intake will then affect blood pressure and heart rate. Mild dehydration will also impact body temperature.

Severe dehydration can cause confusion and weakness, and in extreme situations lead to kidney damage, brain damage, and death. Symptoms of severe dehydration include:

  • very dark yellow or amber colored urine
  • not urinating
  • dry, shriveled skin
  • lightheadedness or dizziness
  • rapid heartbeat and/or breathing
  • sunken eyes
  • listlessness
  • shock
  • delirium or unconsciousness

So, how much water do you need to consume in a day?

The truth is there are no studies or concrete science to answer this question. The National Academy of Medicine suggests the daily adequate intake for men 19 years and older consume 13 cups or 104 ounces, while women 19 years and older consume 9 cups or 72 ounces of water per day. The general rule of thumb I tell my clients is to drink half of one’s body weight (pounds/lbs) in ounces a day. So, a person weighing 150 lbs would generally consume 75 ounces of water as a starting point.

However, other factors will play a role in whether or not you need to increase your intake. For example, the intensity of your workouts, how much you sweat, if you are running a fever, or if the temperature outside is extremely hot, dry and/or humid. Based on recommendations from the American Council on Exercise, I suggest adding 7-10 ounces of water every 10 to 20 minutes during exercise. The Centers for Disease Control and Prevention suggest increasing water consumption by 8 ounces every 15-20 minutes when outside in the heat.

Not a fan of plain water?

There are plenty of options to remedy this!

  • Infused water. Consider adding citrus fruits or zest, like lemon, lime, orange and grapefruit
  • Sparkling water. Carbonated, unsweetened waters are not only safe to drink, but delicious!
  • Herbs. Mint, lavendar, lemongrass, basil, and rosemary are great options to add to water and tea.
  • Spices. Ginger, cinnamon, cloves are some great examples!

Still confused on how much water you need to consume in a day, or experiencing symptoms of dehydration despite proper consumption, learn more about me and how I can help you!