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  • Writer's pictureSophie Beaudry

How Does Water Impact Your Muscles?

Whether you’re a high performing athlete or a regular Joe, water plays an important role in your muscle health. Ever wonder why your health practitioner keeps asking you how much water you drink? Well, here's why.

The Impact of Dehydration on Muscles

To start, it is helpful if you understand the definition of dehydration. Dehydration is a term used to indicate a decrease in the amount of water in the body, ranging from mild to severe. Common causes of dehydration can be linked to NOT DRINKING ENOUGH WATER or losing more fluid than you take in. Water can be naturally lost through the body’s normal process of sweating, crying (tears), vomiting, urinating or diarrhea. However, when these fluids aren’t replenished, it can have a direct impact on your body’s ability to function properly and more specifically, on your muscle health.

Muscle cells require water, glucose, and electrolytes to function properly. Not drinking enough water can affect the body’s natural ability to regulate its temperature by disrupting its ability to sweat. Sweating plays a significant role in regulating the level of electrolytes found in the blood. Important electrolytes, such as sodium and potassium, are naturally lost when your body eliminates water by sweating. Therefore, if your body is dehydrated and unable to properly eliminate these fluids, it can cause an increase in the level of electrolytes resulting in muscle cramping and spasms. Also, when your body is able to balance its level of electrolytes correctly, it helps maintain normal muscle function, such as its ability to contract properly.

Being dehydrated can also have a direct impact on the increase in the level of cortisol, also known as your stress hormone, in the body. Once there is an increase of cortisol, it then competes with certain receptors in the body resulting in a decrease in the level of testosterone. Testosterone is a hormone produced by the human body, in men as well as women, which is the primary hormone responsible for muscle growth. Therefore, not drinking enough water can have a direct impact on your muscles by reducing its growth.

Drinking water is important in the maintenance of your blood volume and viscosity. What does this mean exactly? In more simple terms, water ensures that your body is producing the right amount of blood it needs to function properly. It is making sure that your body is making all the blood needed so it can function at its prime. Drinking water also ensures that your blood has the proper consistency to flow, without restrictions, through your body. Therefore, water consumption has a direct impact on your blood volume and viscosity. Not drinking enough water reduces the amount of blood your body produces and affects its consistency. It causes your blood to become thicker and more susceptible to stick the walls of your arteries resulting in a decrease in blood flow.

Why is blood flow important for muscle health?

Blood carries oxygen and nutrients to your muscles. Oxygen is an essential molecule that gives your muscles the energy they need to work properly. Whether you are doing an intense workout or even during everyday life, the oxygen in your blood is used to breakdown sugars in the body, also known as glucose, into usable energy. During exercise, your body works harder and therefore requires more oxygen. Not drinking enough water can consequently have a direct effect on your physical self. Consuming the proper amounts of water prior, during and after your workout can help your body transport the oxygen your muscles need to properly breakdown this glucose into fuel your body can use. It allows your muscles to be able to work longer and harder before they feel tired.

What happens if your muscles don’t receive the oxygen they need? This is known by the term anaerobic, which means oxygen is absent. When your body is unable to deliver oxygen to your muscles, your muscles will turn glucose, a sugar found in your body, into lactic acid rather than usable energy. An increase of lactic acid in the body causes an increase in acidity of the muscle cells and can lead to muscle soreness, spasms, cramps, weakness, and fatigue. Drinking sufficient amounts of water can reduce the level of lactic acid in the blood by ensuring your body is producing the proper volume of blood to transport the necessary oxygen to your muscles.

Proper blood volume and viscosity are also important when it comes to muscle and tissue repair. High-intensity exercise can cause tiny tears in your muscle fibers. Your body then responds to this damage by increasing blood flow to the area resulting in inflammation. This blood increase replenishes the tissues with the oxygen and nutrients it needs and, properly drains the affected area. This process of inflammation usually leads to delayed onset muscle soreness (DOMS) that can last 1 to 5 days following exercise. DOMS is the pain and stiffness felt in muscles days after unfamiliar or strenuous exercise. This is the body’s natural process to heal damaged tissues. If you’re not drinking enough water, your body struggles to bring the proper blood flow to the correct area, affecting its ability to properly fix the damaged muscle cells. However, research suggests that being dehydrated doesn’t increase DOMS. Not drinking enough water doesn’t seem to increase muscle soreness felt by individuals in the days following intense exercise. The level of DOMS seems to remain the same whether you drink sufficient amounts of water or not.

How much water should you be drinking?

Although research is limited on the topic, certain studies suggest that males, 18 years of age and over, should aim to drink 4 liters of water per day and, females, 18 years of age and over, 3 liters. However, a lot of variables play a role in how much water an individual should consume. Although these quantities may be great guidelines to follow, more research is needed to draw stronger conclusions. More research is required to access the amount of water that is needed to allow proper muscle function by keeping additional variables in mind, such as weight, height, body mass index, levels and intensity of exercise, etc.

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Benefits of drinking sufficient amounts of water:

  • Decreased muscle cramping & spasms

  • Reduced muscle soreness and fatigue

  • Allows proper muscle function (i.e., muscle contraction)

  • Allows effective muscle growth

  • Helps with muscle repair

  • Allows your muscles to work harder and longer

Fun fact:

  • Research suggests that the amount of water you ingest doesn't have an impact on delayed onset muscle soreness (DOMS)


Dehydration and Symptoms of Delayed-Onset Muscle Soreness in Hyperthermic Males by CLEARY, M.A. et al.

Dehydration and Symptoms of Delayed-Onset Muscle Soreness in Normothermic Men by CLEARY, M.A. et al.

Muscle Cramping During Exercise: Causes, Solutions and Questions Remaining by MAUGHAN, R.J. & SHIRREFFS, S.M.

Pilot Study: Effects of Drinking Hydrogen-Rich Water on Muscle Fatigue Caused by Acute Exercise in Elite Athletes by AOKI, K. et al.

Skeletal Muscle Volume Following Dehydration Induced by Exercise in Heat by HACKNEY, K.J. et al.


This blog-post should not be interpreted as a systematic review. The information posted here was built on the scientific articles that I had at my disposal, which were interesting to me and relevant to the topic. Please feel free to comment below any links to scientific articles that are related to the subject.


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