Signs of Dehydration: How Much Water Should You Drink?

Dehydration is defined as losing more fluids than you’re taking in. Aka: Net Water Loss from the body. 

Simple. However, we don’t always have an accurate gauge of water LOSS and it can be challenging to stay on top of water intake. 

The effect of dehydration is a state called hypohydration: hypo, meaning “under”, hydration. Mild hypohydration can be a 1% water loss or less.

Let’s think about how we lose water:

  1. Sweating due to heat, exercise, or physiological stress
  2. Urination (which can be in excess with kidney dysfunction, diuretics, hyperglycemia, or other conditions)
  3. GI Tract via diarrhea or vomiting 
  4. Respiratory Tract, exacerbated with asthma, COPD, apnea, and heavy breathing

Related: Mindful Eating: Finding a Healthy Relationship with Food

LMNT Electrolytes for Dehydration

However, our fluid balancing system is highly evolved (and quite precise). 

Thirst is a key modulator here. When our blood volume drops too low, our hypothalamus (the brain’s master regulating gland) receives a warning. The hypothalamus gives us the sensation of thirst, while at the same time stimulating the pituitary gland to release a hormone called Anti-Diuretic Hormone (ADH). This hormone tells our body to hold onto water, making your kidney slow down and decreasing urination. Simultaneously, the renin-angiotensin-aldosterone system is at work, another trio of hormones promoting fluid and sodium retention. 

Fluid Balancing System in the body
from Frontiers In Pediatric Nephrology


These are the key warning signs of dehydration, indicating you are in a hypohydrated state. They can all manifest differently in people and conditions. Note that a combination of many (or all) indicates severe dehydration.

  1. Thirst – With our advanced fluid balancing system at work, it makes sense that THIRST is an early sign of mild or moderate dehydration. If you are in-tune with this, simply drinking to thirst should keep you in a hydrated state. 
  2. Urine Output – Since urinary output drops when you are dehydrated, this can be a secondary sign of low water status. Further, checking the color of your urine can help determine hydration status. Dark, amber colored urine indicates a hypohydrated state. 
  3. Dry Skin and Lips – There are certainly other factors at play with skin (zinc, Vitamin A, Fatty Acids), so this is only a secondary marker of dehydration when correlated with other signs. 
  4. Fatigue/Headache/Brain Fog – Again, these things can easily be attributed to other causes BUT the reality is that when you are dehydrated you’re likely to experience some degree of malaise/fatigue, a headache, and mood or cognition changes. One study showed mild dehydration resulted in more errors on a cognitive test. (Similar to that of someone drunk!)
  5. Low Blood Pressure – Most of your blood volume is water. When you lose water, your blood volume decreases, which decreases blood pressure. This is seen in more severe cases of dehydration. 
  6. Nausea/Dizziness – Related to blood pressure, when your blood volume drops less blood reaches the brain. The early warning sign of this is lightheadedness when going from sitting to standing. It can also manifest as low-level vertigo or nausea. 


Given our evolved fluid-balancing system it should be simple: Drink to Thirst. 

However, often when we are in a dehydrated state we also need to replenish electrolytes like sodium, potassium, and magnesium. Drinking plain water when already depleted makes this imbalance worse. The symptoms of hyponatremia (low blood sodium) mimic and worsen those of dehydration. 

How to stay hydrated how much water should you drink
Intense hydration battle.

A better strategy? Add Electrolytes. 

In order to stay in a well-hydrated state, a good baseline is half your body weight in ounces per day. Set daily reminders to make sure you’re getting in enough fluid. SOME of that water should have electrolytes and LMNT is the perfect ratio of sodium:potassium:magnesium. PLUS it tastes delicious. 

LMNT Electrolytes Deal

I recommend one packet a day combined with plenty of pure, filtered water. Worried about too much sodium? Check out this post

My favorite way to #staysalty is to add Watermelon Salt LMNT to my Yeti and sip it throughout the day. On chilly mornings, I’ll make a Hot Chocolate Salt as a special treat. 

DeHydration water and electrolytes

Try LMNT for yourself here. Then come back and let me know your favorite flavor!

Add Electrolytes and stay on top of your hydration!

Think LMNT is too salty? You can find other tasty electrolytes at Thrive Market!

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DISCLAIMERS: The statements made on this website are not intended to diagnose, treat, cure, or prevent disease. You assume full responsibility for how you use this information. Always consult with your physician or other health professionals before making any diet or lifestyle changes. This post may contain affiliate links whereby if you purchase these products I receive a small percentage of the sale price. This allows me to keep the blog running and I thank you for allowing me to do that!


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