What is Muscle Fatigue?
Muscle fatigue is tiredness and weakness felt in the muscles. It can interfere with the ability of muscles to function properly.
When you begin exercising or doing daily tasks your muscles might start off strong and able but then tire rapidly. You might also find the fatigue lasts for a while and your muscles take longer to recover.
There are physical and psychological factors that can contribute to muscle fatigue, as well as infections and diseases. We will detail some of the main causes.
Exercise and Physical Activity
Any type of physical activity reduces the body’s energy reserves. The more intense and longer the activity, the bigger the depletion.
The effects of exercise cause increased demand in the circulatory and respiratory systems as the muscles demand more energy. Stored energy is provided from elsewhere in the body.
As the muscles work they also send signals to the brain. Eventually as a result of increased activity throughout the body, our brain tells us our muscles are tired.
The higher intensity the exercise, the quicker the effects of muscle fatigue will be felt. (1)
Lack of Exercise
Lack of condition in our muscles can contribute to muscle fatigue. This deconditioning is often the result of a sedentary lifestyle.
When we don’t exercise regularly muscles gradually “waste” as some muscle fibers are replaced with fat. Consequently when you do any physical activity your muscles tire quickly and exercise becomes more difficult. This is reversible with regular exercise regimes. (2)
Many changes happen in our bodies as we age. One of these is the tendency to have weaker muscles as they lose bulk and strength. The result can be muscle fatigue. (3)
Viral infections and illnesses like influenza can generally leave us feeling weak, they are often the cause of muscle fatigue.
The brain could be telling our body that we need more time to recover, suppressing the urge for physical activity. It could also be as a result of inflammation caused by the virus.
Other viral infections which result in muscle fatigue are HIV, hepatitis, glandular fever and lyme disease. Less frequent infections are malaria, syphilis and tuberculosis. (4)
During pregnancy distribution of body weight shifts and more stress is put on the lower back as the abdominal muscles stretch. This can result in muscle fatigue.
There are things that can be done to help relieve lower back pain and muscle fatigue. These include gentle exercise, supporting the back when sitting and not sitting for too long. (5)
Depression and Anxiety
These psychological conditions can have a detrimental effect on many aspects of daily life. Even though muscle functions normally people with these conditions may perceive muscle fatigue. (6)
Chronic Fatigue Syndrome
Chronic fatigue syndrome is a long term illness affecting people’s energy levels and sleep patterns. They constantly feel tired, listless and unable to carry out routine daily activities. One of the symptoms of this condition is muscle fatigue. (7)
During bouts of exercise the body produces high amounts of lactic acid which can build up in the muscles. This can, in turn, contribute to muscle fatigue. (8)
If the flow of oxygenated blood to the brain is interrupted or blocked a stroke can occur and brain cells can be damaged.
Recovering from a stroke can leave a person with many challenges, one of which is muscle fatigue. (9)
This is a group of autoimmune diseases that affect the muscles. These types of disease happen when the immune system which normally protects our body turns against us.
They might be caused by exposure to something toxic, medicine or an allergic reaction. Additional causes include rheumatic conditions, cancer or other infectious agents.
The symptoms typically include muscle fatigue and weakness. (10)
Chronic diseases can impede many aspects of a person’s life. These include:
Peripheral arterial disease is a circulatory condition which restricts blood flow to the lower limbs. Narrowed arteries mean that the muscles in this region are not supplied with enough blood. The result is muscle fatigue and pain. (11)
Type II Diabetes is a metabolic disorder characterized by insulin resistance and high blood sugar levels. As well as symptoms of frequent urination, increased thirst and weight loss, it also causes muscle fatigue. (12)
Heart failure happens when the blood supply does not meet demand. Either the heart does not get sufficient blood to pump or cannot pump with enough force to meet the body’s needs. Muscle fatigue is one of the consequences of this chronic condition. (13)
Respiratory diseases which come under chronic obstructive pulmonary disease (COPD), include asthma, pneumonia, and lung cancer. The added strain they put on breathing can cause fatigue in muscles which enable this essential process. (14)
This rheumatic condition is thought to be associated with abnormal levels of chemicals in the brain. It alters the way the brain, spinal cord and nerves interpret pain messages carried around the body.
Muscle fatigue in this disorder is perceived rather than actual due to the dysfunction of the central nervous system. (15)
Muscle function affects many bodily functions, they balance energy levels and help the whole body move.
When they are fatigued or weak our ability to carry out physical activity is severely impaired.
Muscle fatigue is a symptom in itself of various factors which affect the muscles. As well as weakness you may feel pain or soreness and suffer cramps or muscle twitches. (16)
The causes of muscle fatigue are varied and numerous which means diagnosing the reason can be a challenge for medical professionals.
If your fatigue is as a result of over exercising, it will likely resolve after rest. However, if the reasons are unexplained you need to see your doctor.
They will want to know the symptoms and how long you have been experiencing them. Others pieces of valuable information point towards whether the fatigue is constant, improving or worsening. Tell them of any medications you are taking and also if you have travelled abroad.
A physical examination will enable a doctor to ascertain whether the fatigue is actual or perceived. They will see whether your muscles are sore, which might indicate inflammation.
Nerve function may be checked to find out whether messages from the brain are getting through to the muscles. They might also see how well your balance and coordination is working.
Further tests may include blood tests or imaging tests to rule out any potential underlying causes.
What is muscle fatigue? Muscle fatigue is tiredness and weakness felt in the muscles. It can interfere with the ability of muscles to function properly.
What causes muscle fatigue? Muscle fatigue can be real or perceived depending on the cause. It could be the result of exercise, or a lack of, neural conditions, chronic diseases, pregnancy or psychological issues.
How do doctors test for muscle fatigue? Diagnosis of muscle fatigue can be challenging and may require blood tests, imaging tests, mobility tests and neural function tests.
When should I go to the doctors with muscle fatigue? The main reason for fatigue is if you have over exerted yourself physically. However if there is no apparent cause then you should seek medical advice.
Can you prevent muscle fatigue? Many of the reasons for experiencing muscle fatigue cannot be prevented. The one thing you can do something about is overextending yourself physically. Make sure you warm up and stretch properly before exercising and don’t push your limits. Cool down stretches are also important after exercise. Stay hydrated and eat a healthy diet.
What can relieve muscle fatigue? Feeling muscle fatigue after exercise can be helped by rest and relaxation. Other causes can be relieved by diagnosis of the contributing factors and subsequent treatment.
Are there any natural remedies for muscle fatigue? Ginseng has been used for many years in alternative medicines. It can improve the effects of muscle fatigue and also extend exercise capabilities. Rhodiola rosea is commonly used in folk medicine in China and Eastern Europe, it can relieve fatigue and again promote endurance. Garlic also helps prolong exercise time and counteract fatigue. (17)
Should I take nutritional supplements for muscle fatigue? There are many supplements which are popular with athletes, and some are even approved by the International Olympic Committee. The ones commonly used are vitamin/mineral supplements, sports drinks, protein supplements and creatine. (18)
Muscle fatigue is tiredness and weakness felt in the muscles and what interferes with their ability to function properly.
Many conditions can factor in muscle fatigue, some will be obvious and easily correctable while others may pose a challenge. Diagnosis, whilst not always easy, is crucial for obtaining the right treatment to relieve symptoms.
Fortunately there are things that you can do to prevent and relieve exercise induced muscle fatigue. Ensuring you warm up and cool down properly, eat a healthy diet and stay hydrated will all have a positive outcome. Also remember not to push yourself too hard, that extra mile running could mean a few more days of rest.
It’s also a good idea to keep yourself moving, even if it’s only a short walk each day. Regular exercise can improve the strength and health of your muscles.