What Is Muscle Fatigue: Know Everything About It

Muscle pain is the most commonly experienced phenomenon that everyone faces in their life. Sometimes heavy exercise causes muscle pain, and sometimes other factors contribute to the development of muscle fatigue1. This article not only covers what is muscle fatigue but also its treatment. So read it thoroughly to get the whole information.

When muscles feel exhausted due to continuous movement, this results in muscle weakness. This state of muscle weakness and tiredness leads to muscle fatigue.

But what is muscle fatigue and what are the reasons for the occurrence of muscle fatigue2, if you also have such questions then this is a perfect post for you. Here is the answer to all your questions regarding muscle fatigue.

Let’s dive into this complete guide on what is muscle fatigue.

What is Muscle Fatigue

Muscle fatigue is a condition that arises when muscles lose energy and feel tired. As a result muscle movement is also get affected. Muscle contraction also decreases in this state.

This is just like when you perform some task after some time you feel low. A similar thing happens with your muscles when you use them for a long time. Muscle fatigue makes muscles weak and also decreases muscle movements.

Well, the chances of muscle fatigue are quite common during exercise. Hence, doing every task or exercise within the muscle strength limits is important.

Muscle fatigue also results in the decline of muscle performance. It is mainly observed in sports persons and athletes. Among athletes, this is the biggest problem as it limits athletic performance.

It is not good for health and physiological process. Because every movement in the body is the result of muscle contraction which is get affected in case of muscle fatigue.

Whenever you feel your muscle movement is decreasing and you can’t feel to move your muscle, this is the state of muscle fatigue.

Now, you know what is muscle fatigue. But this is not enough information. What are the causes of muscle fatigue, is important to know. Not only for knowledge but also for reducing the risk of muscle fatigue. So keep hovering on this article about what is muscle fatigue.

Muscle Fatigue Causes

The most common cause of muscle fatigue is exercise and physical activities. There are many other factors responsible for the cause of muscle fatigue. These are including

1. Heavy Exercises

One of the major causes of muscle fatigue is intense or heavy exercise. During an intense workout, muscle cells utilize the stored ATP for energy. The requirement of ATP is done through the process of glycolysis and oxidative phosphorylation in which the production of ATP takes place.

During this process, muscles don’t get enough oxygen. That’s why anaerobic respiration takes place to generate energy in which lactic acid is formed. Lactic acid causes muscle pain and the excess accumulation of it leads to muscle fatigue.

2. Muscle Injury

Any damage or injury to muscles also causes muscle fatigue. Due to any muscle injury, muscle strength gets affected. Muscles become weak and lose the ability to contract. In some cases, injury breaks the connection between muscle and the central nervous system.

Muscle injury damages the muscle fibers as a result their strength decreases. Inflammation and swelling also occur in the injured muscles. And ultimately it causes tiredness or weakness in the affected muscle area.

3. Infections

Infections are also a major cause of muscle fatigue. Mostly viral infections are responsible for muscle fatigue. Any kind of infection in muscles leads to inflammation in the muscle fibers that ultimately give rise to pain and soreness in muscles.

Some bacteria are also responsible for the damage to muscle cells. The infection makes the immune system weak as a result muscle movement and muscle contraction also decrease.

4. Natural Aging

Well, natural aging is an inevitable process that is going on till the end of life. And with the increase in age of a person, the ability to perform daily tasks declines, and also muscular movement becomes slow.

This is all due to the increased rate of muscle protein degradation 3and decreased rate of muscle protein synthesis. When the deficiency of contractile protein occurs, the muscles will not do contraction which finally results in a decrease in muscle strength and muscle fatigue. That’s why the risk of muscle fatigue increases with an increase in age.

5. Pregnancy

Pregnancy is a crucial and memorable period in a woman’s life. But during this time many women show issues of muscle fatigue. Well, the stomach muscles are mainly affected in this case.

During pregnancy, so much is going on inside the mother’s body as a result mother feels so much tired. Although she didn’t even do lots of work, still feel exhausted. This is because of continuous muscle movement or contraction.

6. Continuous Chronic Diseases

There are various chronic diseases that are associated with muscle fatigue4. Due to chronic diseases, the body’s functioning abilities go down and the body becomes so weak. Muscle fatigue is the result of weakness in muscles.

Every part of the body performs a specific function and for that muscular contraction is very essential. Hence, any chronic disease will affect muscle contraction and ultimately causes muscle fatigue.

Chronic diseases like heart disease, diabetes, chronic lung disease, anemia, kidney diseases, and peripheral arterial disease, all make your muscles weak and fatigued. As a result, people suffering from such chronic diseases show the symptoms of fatigued muscles.

What is muscle fatigue and what are its causes? Now it is clear. But what are the symptoms linked with muscle fatigue? If you want to know about it then scroll more.

Muscle Fatigue Symptoms

Muscle pain
Image by spukkato on Unlimphotos

Muscle pain and soreness are common symptoms experienced by people during muscle fatigue. As it is not restricted to any part of the body hence it can occur anywhere. And it leads to muscle weakness. That’s why it is very important to prevent the risk of muscle fatigue by reducing its symptoms at the initial stage.

But this is not the only symptom associated with muscle fatigue. Some other signs occur in fatigued muscles.

1. Muscle Cramps

The most common symptom of muscle fatigue is muscle cramps. This is due to the overload of skeletal muscle. A muscle cramp is directly associated with the accumulation of lactic acid. This is not much harmful and can be cured easily. Proper hydration and muscle stretching will be very effective to prevent muscle cramps.

2. Soreness

Muscle soreness is just like muscle pain or ache, which happens due to the accumulation of lactic acid in muscles due to anaerobic respiration.5 It can be easily identified as a burning pain in muscles after high-intensity exercise.

3. Muscle Twitching

Muscle twitching or muscle fasciculation is a feeling of small muscle contraction. The contraction in muscle fibers are happen without control. Sometimes you don’t even feel the muscle twitching. But never ignore this symptom as it is directly related to nervous system damage. It is the reason for muscle fatigue and other muscle illnesses. Yoga, meditation, stretching, and simple exercising help to prevent muscle fasciculation.6

4. Trembling

In many cases of muscle fatigue, people experience trembling in muscles. Sometimes anxiety will be the reason for a person’s tremors, but when it happens after exercise, there are more chances of it due to muscle fatigue.

The shaking and trembling of muscles show a decline in the level of glucose.

5. Shortness of Breath

This is quite shocking but it is true. Shortness of breath occurs when you have muscle fatigue. Breathing is a process in which not only the exchange of gases takes place but also the movement of intercoastal and abdominal muscles takes place. Hence it is clear that any muscular disease directly affects breathing and causes shortness of breathing.

That’s why whenever you experience shortness of breath then pay attention to it as it might be a sign of a muscular issue.

Out of all these symptoms, there are many other signs your body starts showing when you have muscle fatigue. You can’t able to perform your daily task with that strength or capacity from which you usually do. And also you can easily feel some kind of weakness in muscles.

Muscle Fatigue Types

To understand better what is muscle fatigue, see how many types of muscle fatigue are there. Well, there are mainly two categories of muscle fatigue. One is central fatigue and another one is peripheral fatigue.

Peripheral Fatigue

Peripheral fatigue is observed when muscles can’t able to respond and do muscle contraction to the signals transmitted by the brain. In this case, the central nervous system functions very well and sends all the signals to the target muscles. But there is a problem at the end of the muscular level.

The reason for its occurrence is mechanical stress, weight training, continuous exercising of muscles, and prolonged muscle activity.

Central Fatigue

Central fatigue is directly related to the central nervous system. Here, some sort of chemical change occurs in the brain that disturbs the communication between the brain and muscles. Therefore, central fatigue affects both brain function as well as muscle function.

The risk of central fatigue is more in people who don’t take enough sleep or rest and do a lot of muscle and mental work. Sufficient sleep is very important for the functioning of the brain and muscle movements decrease.

No matter which type of muscle fatigue condition arises in your body the important thing is to take medical assistance. Otherwise, it will lead to more serious health conditions.

Muscle Fatigue Diagnosis

Generally, the diagnosis of all muscle problems has been done through electromyography and muscle biopsy. These techniques will help to detect damage to muscle tissues. Diagnosis is very essential to make sure that medical attention is needed or not.

Muscle fatigue is a situation in which muscle damage happens because of the prolonged activity of muscles. And this results in a decrease in the muscle’s ability to generate force as well. All such health conditions are quite observable.

Hence, simple observation of a person’s physical performance gives an idea about muscle fatigue. But sometimes only observations are not enough. So, for the proper and accurate diagnosis, some tests must be performed. These diagnostic tests or techniques are such as;

Surface Electromyography

It is the best method to detect muscle fatigue. In this method, electrical signals are used to check muscle activity.


In Mechanomyography the mechanical activity of muscles is used to detect muscle fatigue.

Muscle Fatigue Treatment

The knowledge about what is muscle fatigue will be incomplete without knowing the ways of treating muscle fatigue. Therefore, here are some ways or treatments useful to reduce muscle fatigue. These treatments show positive results on any kind of muscle fatigue whether it is skeletal muscle fatigue or neural muscle fatigue.

So try out them for relieving muscle fatigue and improve muscle performance. 7But do not consider these methods as the final solution for treating muscle fatigue. Before trying anything first consult your physician.

And the most important thing is always trying to take a healthy diet, keep yourself hydrated, do a little bit of stretching, and maintain a balance between work and life. What is muscle fatigue? This will be completing after knowing about treatments.

1. Exercises and Therapies

Exercising muscles will be very effective not only for muscle fatigue but also for muscle performance. If you do weight training or any resistance training then always end with some aerobic cool-down exercises.

Endurance training increases the amount of by-product, lactic acid in the muscles. That is responsible for muscle fatigue. So a light exercise on the next day of endurance exercises helps to reduce all the accumulated lactic acid.

Stretching is also very important to reduce muscle fatigue. Doing some stretches and warm-ups before and after the workout or heavy exercises reduces the risk of any muscle injury.

Hot and cold therapy is very effective for relieving muscle fatigue and inflammation in fatigued muscles. It is also good for skeletal muscle fatigue.

2. Medications

In sports, muscle fatigue negatively affects the athletic achievements of a sports person. Some natural and synthetic products help to reduce muscle fatigue. Caffeine is one of the most popular synthetic substances used by many sports persons to reduce muscle fatigue.

Ephedrines and amphetamines are other synthetic products that promote resistance to muscle fatigue. They are also used to enhance athletic performance.

Ginseng herbs and garlic are the natural substances used to reduce muscle fatigue.

3. Dietary Supplements

Dietary supplements play a significant role in the treatment of muscle fatigue. Nutritional supplements help to improve muscle performance as well as muscle strength. So take a diet rich in nutrients, vitamins especially vitamin D, and other essential minerals.

Creatine is good for muscle health and it is present in seafood and red meat. The naturally occurring acid, ergogenic acid is also very effective in reducing muscle fatigue as well as improving muscle cells.

4. Sports Foods

What is muscle fatigue for a sports person? For sports persons, daily physical workouts and training are part of their life. Therefore they need to take a nutrient-rich diet. Sports food contains all the required nutrients that increase athletic performance.

Sports foods are good for athletes not only to improve muscle performance but also for muscle fatigue. But there is not much research-based evidence that proves sports food can be used to treat muscle fatigue.

The best example of sports food is the energy drink red bull, which gives instant energy and improves athletic performance.

Other Muscle Disorders

Now, you have a general understanding of what is muscle fatigue, but do you have an idea that there are many other muscle disorders that are responsible for the reduction in muscle performance?

Various other muscle disorders including,

#1 Muscular Dystrophy

Muscle dystrophy is a genetic disorder that occurs due to the mutation of a gene involved in the synthesis of proteins required for muscles. It leads to progressive muscle weakness and also reduces muscle mass.

The health of muscle fibers is regulated by specific proteins whose synthesis depends on certain genes. If any defect takes place in those genes the risk of muscular dystrophy increases. And it is a hereditary disease hence it can be transferred from one generation to another.

It not only affects muscle movement or daily activities but also affects breathing function.

It is similar to muscle atrophy. To know more about muscle atrophy, click here.

#2 Neuromuscular Fatigue

Neuromuscular fatigue8 is the result of damage to the central nervous system and muscular system. In this condition, locomotor functioning is get affected. Due to this the person’s ability to generate force for any body movement or performing any task.

The muscle movement is decreased or sometimes muscles don’t even move according to the signals. This happens because of the inability of the brain to give response to the signals. In the absence of stimulation, muscles are not able to do contractions. Therefore, their movement is also get restricted. Both types of muscle movement, voluntary and involuntary muscle movements get affected by neuromuscular fatigue. Various therapies and medications are used to treat neuromuscular fatigue.

#3 Myositis

It is a condition in which muscle inflammation occurs in the shoulders, thighs, and hips area. This is a rare muscle condition. It can happen due to infection, inflammatory diseases, and autoimmune diseases. Myositis results in muscle fatigue, problem in walking, and any muscle movement.

It has two specific kinds such as polymyositis and dermatomyositis. Polymyositis is linked with the muscles of limbs while dermatomyositis is related to the skin. In both kinds of myositis, muscle fatigue usually happens.

For its treatment, corticosteroid drug doses are used by doctors. Other medications, physical therapy, and treatments are also helpful to cure myositis and its further complications.

#4 Myasthenia Gravis

This kind of muscle fatigue occurs due to the breakdown of communication between muscles and the nervous system. As a result muscle movements decrease and sometimes people are not able to move their muscles. Generally, voluntary muscles are get affected in myasthenia gravis.

Through studies, it has been found that it is quite common among younger women than men. It occurs in people of age between 40 and 60. Due to myasthenia gravis, muscles become so weak that it is going to be difficult to move them. The initial sign of this disorder is seen in eye muscles.

Voluntary muscles are affected by this disease hence, the muscles of the face, throat, limbs, eyes, and neck shows the symptoms of muscle weakness and muscle fatigue.

#5 Fibrositis

Fibrositis is associated with musculoskeletal muscle fatigue9. It causes muscle pain and stiffness. It also causes sleeping problems and mood change issues. The main cause of fibrositis is emotional imbalance and stress.

That’s why doctors use physical therapy, talk therapy, and stress and anxiety relieving activities against fibrositis or fibromyalgia. In chronic fibrositis, salicylates are used to give relief to its symptoms. It usually occurs in people in the age group 40 and above.

#6 Sarcopenia

Sarcopenia develops in older people, due to the loss of muscle movement in the involuntary muscles. Because of that their physiological functions get affected and they feel weakness in their body. The muscle mass and muscle strength of skeletal muscles get reduced in this case.

As it is happened due to the natural aging process so it occurs mostly at age of 60 but in some cases, it occurs at the age of 30 or 40. People with sarcopenia have difficulty in doing any task, slow muscular movements, muscle fatigue, and falling.

#7 Chronic Fatigue Syndrome

It occurs when extreme fatigue induced in the muscles leads to a decline in physical functioning. According to the researchers, the cause of CFS or myalgic encephalomyelitis is not clear but multiple physiological and pathological factors contribute to its cause.

Sometimes psychological factors are also the cause of it. People with CFS have muscle fatigue, sore throat, sleeping problem, muscle or joint pain, and cognitive issues.

Final Note

No matter which muscle disorder you have, never neglect any symptoms related to muscle problems. This information on what is muscle fatigue makes you aware of muscle-related disorders. Through this article on what is muscle fatigue, you become aware of muscle health. Don’t do high-intensity exercise when you have severe pain in your motor units as this is a sign that you have to seek medical attention for relieving muscle fatigue.

Now you know what is muscle fatigue and also some other muscle diseases. This information will be helpful for you to keep your muscles healthy. Let us know in the comment which section of this article what is muscle fatigue, you find completely unknown.

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Laveleena Sharma

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