Muscle fatigue is the reduction in the capability of muscles to perform work. It can be associated with a state of exhaustion, which can occur due to exercising or other strenuous activities. Muscle fatigue makes it hard to move normally. It can make people tired and leave them energy deprived.
This is because muscle fatigue decreases the force behind the movement of muscles, causing a person to feel weaker.
A lot of people experience muscle fatigue, and in most cases, it is minor. However, a few people may take a longer time to recover from muscle fatigue. They may require medical intervention.
The onset of muscle fatigue has hampered many athletes from achieving their maximum potential.
How’s Muscle Fatigue Caused?
It can happen due to either or both of the following:
-The nervous system fails to generate a sustained signal with muscle tissue
-The contraction ability of the muscle is reduced
Lactic Acid Build Up and Muscle Fatigue
Anaerobic metabolism is a process in which the body produces energy without using oxygen. This commonly occurs during periods of intense physical activities (exercises). During this process, lactic acid is released as a byproduct. Small amounts of lactic acid operate as a temporary energy source. However, when it gets built-up in the muscles, you feel the “burning sensation.” If the lactic acid is not cleared quickly, it can lead to muscle fatigue. For this reason, it may be desirable to reduce lactic acid build-up in the muscles
How quickly lactic acid is cleared, and in turn, the fatigue onset is influenced in part by genetics.
How Does Genetics Influence Muscle Fatigue
MCT1 Gene and Muscle Fatigue
MCT1 gene, also called SLC16A1, encodes the Monocarboxylate transporter 1 (MCT) protein. It regulates the transport of lactate and other substances. It also removes lactic acid from the muscles.
MCT1 gene influences the amount of MCT you produce. The more you produce, the quicker is the clearance rate. This delays the onset of muscle fatigue.
rs1049434 of MCT1 Gene and Lactic Acid Clearance
rs1049434 is an SNP in the MCT1 gene. This SNP affects lactic acid clearance by influencing the amount of MCT produced. According to a study on a group of moderately active men and women, it was observed that individuals with the AA type had higher levels of lactate compared to the TT type.
Other genes like_ COL5A1, HNF4A, TNF, and _NAT2 also influence the likelihood of fatigue.
Health Conditions That Contribute to Muscle Fatigue
- Anemia
- Addison’s disease
- Anxiety
- Botulism
- Cerebral palsy
- Chronic fatigue syndrome
- Depression
- Fibromyalgia
- Hepatitis C
- HIV
- Hypothyroidism
- Influenza
- Muscular dystrophy
- Myasthenia gravis
- Stroke
- Tuberculosis
Effects of Lactic Acid Build Up
The build-up of lactic acid is characterized by symptoms like:
- Nausea
- Fatigue
- A burning sensation in the muscles
- Weakness
- Muscle soreness
- Muscle cramping
- Shortness of breath
- Yellowing of skin or eyes
Recommendations To Reduce Lactic Acid Build-Up and Delay The Onset Of Fatigue
Adequate Magnesium Levels
Magnesium delivers energy to the body while exercising and helps limit lactic acid build up.
Foods rich in magnesium include legumes like navy beans, pinto beans, kidney beans, and lima beans, seeds such as pumpkin, sesame, and sunflower seeds, and vegetables like spinach, greens, turnips.
Adequate Rest Periods
Getting enough rest aids muscle recovery as well as the breakdown of lactic acid
Adequate Omega-3 Fatty Acids
It helps the body to break down glucose and thus can help to limit the body’s need for lactic acid. Food sources of these fatty acids include fish like salmon, tuna, mackerel, nuts and seeds like walnuts and flax seeds, and plant-based oils such as olive oil, canola oil, rice bran oil.
Adequate Vitamin B
B vitamins help to transport glucose throughout the body and help provide energy to the muscles. Food sources of B vitamins include leafy green vegetables, cereals, peas and beans, fish, beef, poultry, eggs and dairy products.
Eat Before Working Out
Eating a healthy meal can help prevent muscle soreness.
Summary
- Muscle fatigue is usually a result of vigorous exercise and is associated with a state of exhaustion. Over time, muscle fatigue can lead to reduced performance of muscles.
- During exercise, energy is produced in the absence of oxygen, a process called anaerobic metabolism. The byproduct of this process, lactic acid, fuels the body’s energy needs. However, the build-up of lactic acid can lead to muscle fatigue.
- Some genes influence the lactic acid clearance from the bloodstream and muscles. A protein produced by the MCT1 gene is responsible for lactic acid breakdown. The AA type of rs1049434 in the MCT1 gene is associated with lower production of the protein. People with the AA type have a slower lactic acid clearance and early onset of muscle fatigue.
- Other health conditions like fibromyalgia, depression, anemia, anxiety, hypothyroidism, and tuberculosis can also lead to lactic acid accumulation.
- Some telltales of lactic acid build-up include nausea, vomiting, fatigue, muscle cramps, and yellowing of skin/eyes.
- Consuming adequate dietary sources of magnesium, B vitamins, and omega-3-fats can help clear lactic acid and delay the onset of fatigue. Some workout tips to prevent lactic acid build-up include eating healthy food before exercising and taking enough rest between workouts.
References
https://pubmed.ncbi.nlm.nih.gov/3471061/
https://en.wikipedia.org/wiki/Monocarboxylate_transporter_1
https://pubmed.ncbi.nlm.nih.gov/22516692/
http://ajcn.nutrition.org/content/84/2/419.full
