How to Check Hydration Levels


Hydration can affect your performance either negatively or positively.

The reality is, most of us pay some attention to drinking when we feel thirsty, but we don’t really take into consideration how dehydration can affect our health.

But learning how to check hydration levels can help you to maximize your training and give you an advantage over other athletes if you compete competitively.

It may seem like an insignificant thing, but getting into the habit of monitoring your hydration throughout the day can be life-changing and performance-boosting.

Let’s have a look at how to check hydration levels to ensure optimal health.

Why Do We Need to Stay Hydrated?

Staying hydrated and drinking plenty of water is vital, as your body uses it in a host of bodily functions that keep us going all day, every day.

As you go about your daily activities, you lose water just by breathing, perspiring, and urinating. This means you need to replenish the lost fluid.

Your body uses water to create saliva and mucous that keeps your eyes and nose moist. It also uses water to cushion and protect your spine and brain by acting as a shock absorber.

Even your joints use water, as the cartilage that prevents your bones from rubbing against each other consists of 70 to 80 percent water.

Water helps to regulate your body temperature, as well as dissolving minerals and nutrients that are then carried by water—along with oxygen—in the bloodstream to every cell in your body.

To effectively flush toxins, acids, and waste products from your body, your kidneys need water. If you’re not sufficiently hydrated, the waste products can accumulate, which can lead to them sticking together to form kidney stones or crystals.

Even mild dehydration can lead to an increased growth of bacteria along the lining of the bladder and urethra increasing your risk of a UTI.

Drinking plenty of water will help you maintain blood pressure levels, healthy digestion, and enhance both mood and concentration.

By making sure that you remain sufficiently hydrated throughout the day, you’re improving your overall health and body functions.

How Much Water Should You Drink Each Day?

The most common recommendation is to drink six to eight 8-ounce glasses of water every day.

However, the amount of water each person needs to drink each day would vary based on the following:

  • Climate you live in
  • How much you weigh
  • How physically active you are
  • The amount you sweat

Research has shown that the general recommendation for an adult male is about 125 ounces—3.7 liters—daily, while an adult female should drink 91 ounces—2.7 liters.

You should also keep in mind that about 20% of your daily fluid intake should come from the fruit and food you eat throughout the day as well.

Runners would need to drink more water on a daily basis than average, and you would need to adjust the fluid intake based on the intensity and duration of the run as well. A good rule of thumb is to drink 1 liter of water for every 1,000 calories burned.

As an example, if you weigh 160 pounds and run for 60 minutes at 6 minutes per mile, then you could burn up to 1219 calories. If you’re running five miles a day, you could be burning up to 2,500 to 3,000 calories in one run!

How Does Dehydration Affect Your Performance?

Dehydration, even if it’s mild, will negatively affect your running performance. You’ll start to notice that you’re feeling fatigued, running at a slower pace, and that you just don’t have the strength to pick up your speed.

Sweat is your body’s response to cool the surface of your skin and regulate your temperature. But when you become dehydrated, to preserve water and protect vital organs, your body will reduce the production of sweat.

Without sweat, your core temperature increases. This can lead to you developing heatstroke, especially on a hot day.

When dehydrated, your blood volume decreases and it becomes thicker, so your heart has to work harder to pump blood to the body parts.

This reduces the amount of nutrient and oxygen-rich blood that gets to your working muscles, making it increasingly difficult to maintain anything but a slow pace.

There’s also a reduction in your mental performance. Your reaction times become slower and you’ll find it difficult to focus on anything.

Aside from affecting your running performance, dehydration will also have an impact on your recovery. You’ll find that even mild dehydration slows your body’s ability to recover for your run the next day.

What Are the Symptoms of Dehydration?

It’s important to pay attention to your body and the signs of dehydration while running, as most people don’t realize that they’re dehydrated.

The early symptoms of being dehydrated include:

  • Dry mouth
  • Thirst
  • Feeling sluggish

Unfortunately, as we get older we don’t realize that we’re thirsty until we’re already dehydrated.

Without replenishing lost fluids, the symptoms of dehydration will continue to get worse and you may experience the following more serious symptoms:

1. Fatigue

Even mild dehydration can make you feel as though you need to have a nap or that you’re more tired than usual.

As dehydration sets in, your core temperature increases, your blood pressure drops, and the blood flow to your brain is reduced.

This means that your brain isn’t getting enough oxygen, which then induces the feeling of fatigue.

This feeling of fatigue will increase as your dehydration continues to get worse and your cardiovascular system isn’t able to deliver oxygen to your brain and working muscles.

2. Heart Palpitations

As your cardiovascular system is placed under more pressure, you’ll be able to notice the physical symptoms of heart palpitations or an irregular heart beat.

Your heart’s blood vessels’ function will be impaired and this can lead to altered blood pressure regulation, or a reduced amount of blood being pumped out of the left ventricle—reducing cardiac output.

3. Headaches

When you’re dehydrated, your brain will contract or shrink! As it does this, it pulls away from the skull.

This places the pressure on the surrounding nerves, which causes the headache. You may notice that pain increases when your head moves or when you bend your head forward.

Sometimes the pain will be localized to either the front or back of the head, or on one side, but the pain could also be felt throughout your head.

4. Dry Skin and Cracked Lips

When you’re dehydrated, your body will pull water from other parts of the body, like your skin and intestines, to ensure that your vital organs—brain, kidneys, heart—have water to function.

This then leads to your mouth, lips, and skin feeling really dry.

5. Lightheadedness

You may experience lightheadedness or dizziness while you run or when you stop, due to either low-blood pressure or a lower level of electrolytes.

Depending on how severe your dehydration is, you may even faint or you may even feel confused or out of it for a few minutes.

6. Muscle Spasms

As your body tries to preserve normal brain, kidney, and heart function, it will also pull water from the muscles. This will lead to an electrolyte imbalance.

A sodium or potassium deficiency can lead to painful muscle cramps or even full-body cramping.

How to Check Your Hydration Level

Fortunately, there’s a few ways you can take to test yourself to determine if you’re dehydrated throughout the day, both while you’re running and when you’re resting.

Pinch Test

The pinch test—also known as the skin turgor test—uses the elasticity of your skin to show if you’re dehydrated.

To do this, pinch the skin on the back of your hand and watch how long it takes for your skin to return to its normal position.

If you’re dehydrated, your skin will take longer to return to its normal position due to the loss of fluid in the skin. But if you’re sufficiently hydrated, then your skin will snap back into place very quickly.

Bathroom Frequency

When you’re sufficiently hydrated, you should be emptying your bladder every 2 to 3 hours. This means that you could end up going to the bathroom 6 to 8 times per day.

If you’re dehydrated, your body will slow down the production of urine and you’ll find that you urinate less frequently. In some cases, you may only urinate 3 times a day if you’re dehydrated.
Keeping track of how frequently you go to the bathroom will help you keep track of your hydration levels.

Color of Your Urine

One of the best indicators of your hydration level is the color of your urine. It’s important to note that the color of your urine can vary depending on the following:

  • Vitamins you’re taking
  • Foods you eat
  • Over-the-counter and prescription medications
  • Strong color dyes in food

While the color can vary, if you’re sufficiently hydrated, your urine should be somewhere between clear and a pale yellow. If you’re dehydrated, your urine will be a dark yellow, amber, or dark orange.

Thirst/Hunger Level

If you’re thirsty, then you may already be mildly dehydrated. However, the thirst would also be accompanied by other symptoms, like:

  • Dry mouth
  • Irritability
  • Headache
  • Feeling weak
  • Craving sugar or feeling hungry

When your body is trying to maintain its hydration level, it will send a signal to your brain, which is the same signal used when you’re hungry. But instead of “craving water,” your brain interprets the signal as your body needing more food.

So before you reach for that afternoon or after dinner snack, drink a glass of water and wait 5 to 10 minutes. If you were thirsty, you’ll feel satisfied. But if you’re truly hungry, your stomach will start growling again.

It’s important to note that your “natural thirst” will diminish as you get older. This means your fluid levels could drop by 2 to 3 percent before your body signals that you’re thirsty.

Tips to Stay Hydrated

Plan Your Run and Hydration Strategy

Some runners may avoid carrying water with them on a run, as it’s uncomfortable and can be heavy. However, this can lead to dehydration, especially on long runs.

If there are water fountains around your city, try to plan your route so you can pass the water fountains and take a drink. This will allow you to run for longer without needing to carry much water with you.

If there are no water fountains, you can plan a running route that loops back around to your car or home, where you can fill up your water bottle again to ensure you stay hydrated.

Set Reminders on Long Runs

Some of your best thinking can be done while you’re running, with some of the most creative solutions springing to mind mid-mile.

This can make it easy to lose track of when you last had something to drink, which could leave you mildly dehydrated after a run.

Whether you’re going for a quick 45-minute run or a longer 90-minute run, you should set a timer—either on your watch or your smartphone—to go off every 20 minutes.

This will be a good reminder for you to drink or have some form of energy-boosting nutrition, especially if you’re on a longer run.

This will help you to maintain your hydration levels throughout your run.

Calculate Your Sweat Rate

Everyone’s sweat rate is different and it can also vary from one day to the next. By calculating your sweat rate, you can adjust how much fluid you need for each run.

But there are a few factors that can influence your sweat rate. These include:

  • The intensity of your run
  • Humidity and temperature
  • Moisture-wicking and breathability properties of the clothing you’re wearing
  • Your genetics

The best way to calculate your sweat rate is to begin by weighing yourself before your run. Make sure you aren’t wearing any clothes when you weigh yourself.

Then go for your run and don’t forget to take your hydration with you. Try to use a bottle or hydration pack with measurements on it so you can calculate how much you drank.

When you return from your run, weigh yourself again without your clothes on. Take note of the number, as well as how much water you drank from your bottle.

Using your before and after-run weights, calculate what percentage of your body weight has been lost on your run, using this formula:

(Pre-run weight – post-run weight) divided by pre-run weight = X
X x 100 = percentage

This will allow you to calculate exactly how much water your body used in the run, so you can estimate accurately how much you will need for every run thereafter.

You should pair this test with the color of your urine in order to get an accurate idea of your hydration levels.

If you didn’t lose weight during your workout but your urine is clear, then it’s likely that you are drinking enough during your run.

However, if you did lose weight but your urine is dark, you may not be drinking enough water and should increase your intake during your runs.


A large part of hydration is balancing electrolyte levels. An electrolyte imbalance can lead to some nasty symptoms, including:

  • Muscle cramps
  • Digestion issues
  • Nausea
  • Muscle weakness

As you sweat, you lose electrolytes like sodium, potassium, and magnesium. The more you drink, the more your water and electrolytes can become unbalanced.

Electrolytes play an important role in cellular function, nerve function, and muscle function, as well as helping to regulate the body’s pH.

As your sweat rate increases, you should also increase your electrolyte intake in order to prevent unpleasant symptoms.

You can carry some electrolyte tablets with you on your run to keep your levels balanced.

Maintain Your Hydration Levels

We could all do with drinking more water. It is easy to lose track of drinking water throughout the day when you are not running, so don’t forget!

Although drinking tea or coffee during the day does help to keep you hydrated, you should be drinking pure water in between to make up the recommended daily amount.

If you maintain your hydration levels throughout the day, you should find that you’re at much less risk of becoming dehydrated and suffering the negative effects, both in your running performance and everyday life.

Photo of author


Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.